vol. 1. no. 1, sep 2004-abstract - central power research ... no-4_abstract-full_27-07-2017.pdf ·...

Vol. l. No. l, September 2004

ABSTRACT LIST

1. A Novel Control Strategy for TCSC to Damp Subsynchronous Oscillations

Sujatha Subhash, B.N. Sarkar and K.R. Padiyar

Thyristor Controlled Series Compensators (TCSC) is the fi rst FACTS controller under the new generation to have reached mature stage of development. The importance of adding series capacitor to ac transmission lines for increasing line load-ability is known for a long time. But the potential risk of SSR oscillations had made it undesirable to widely use them in the system. Adding a thyristor controlled series compensator Laresen et al (1) is however a fairly recent phenomenon and provides greater fl exibility in power transmission, There are several advantages in using TCSC and reducing the torsional oscillations caused by SSR is one among them. A novel discrete control strategy to mitigate SSR oscillations is proposed for TCSC having discrete type of control over compensation level, since it behaves like a conventional series compensation under normal conditions. The control strategy is based on the Phase unbalance concept and is simple and easy to implement in the hardware. The concept of Phase unbalance originally proposed by A.Edris (2) is described followed by theoretical analysis to support the design for practical implementation. An expression for the damping torque coeffi cient is given, which is useful to assess the damping effectiveness quantitatively, over a wide variety of system operating conditions and for arriving at an optimal design. Extension of this concept to TCSC with discrete control is subsequently explained.

2. Analysis of Northern Region Electricity Board (NREB) Grid Disturbance

P.V. Bala Subramanyam, B.N. Sarkar and V.J. Talwar Santhosh Kumar

The Northern Regional Electricity Board (NREB) consists of generating and transmission power utilities of the states UP, Rajasthan, J&K, Punjab, Himachal Pradesh, Haryana, and the central utilities viz Powergrid, NTPC, NPC, BBMB, DVB etc. NREB is the largest regional electricity board. The NREB grid experienced several major grid disturbances in the recent past resulting in cascade tripping of 400 kV lines and generating units. This resulted in separation of grid into several isolated parts with disruption of power supply. On certain occasions several EHV lines tripped leading to total blackout. This paper deals with the analysis of the grid disturbance that occurred on 26th Nov’96. In this paper main emphasis is given to superimpose dynamic variation of characteristic impedance on relay characteristics. The effectiveness of Power System Stabilizer (PSS) to avoid/minimize such grid disturbances is attempted.

3. Insulation Coordination Studies for 400 kV GIS in a Hydroelectric Project in India

B.N. Sarkar, K.S. Meera, Gaurav Garg, Ram Nath, A.K. Tripathy, S.C. Mishra and J. Thomas

Insulation coordination studies comprising of Switching, Lightning and Very Fast Transient over voltages has been carried out for the 400 kV Gas Insulated Switchgear (GIS) in the Tehri hydroelectric power plant in India. The studies were carried out to decide the various parameters of the switchyard equipment including arrester locations. Results of the switching over voltages have been validated on the Transient Network Analyser (TNA). This paper discusses some of the results of all these studies.

THE JOURNAL OF CPRI - Vol. l No. l, September 2004,


4. Leakage Current and Charge in RTV Coated Insulators Under Pollution Conditions

D. Devendranath, Channakeshava and A.D. Rajkumar

Room temperature vulcanizing (RTV) silicone rubber coating has excellent leakage current suppression characteristics. It is used extensively on porcelain and glass insulators in pollution prone areas as an anti-pollution measure. A pollution aging chamber has been fabricated and an on line 4 - channel personal computer (PC) based data acquisition system has been developed to conduct tests on RTV coated porcelain samples. A study of the dependence of the leakage current and the charge on the fl ow rate, conductivity and pressure of the solution forming the fog is reported. It was observed that a higher charge and a higher average leakage current were obtained at a higher fl ow rate and a higher conductivity. The results with coated HV insulators are consistent with those published in the literature with RTV coated fi ber glass reinforced plastic (FRP) rods.

5. 3D Location of Multiple Partial Discharge Sources

H.N. Nagamani and Channakeshava

The ability to locate Acoustic Emission (AE) sources is one of the most important features of the multi-channel AE detection system. An array of AE sensors is necessary to locate an AE source. When the AE signals are transient in nature, measurement of time of signal arrival at different AE sensors is generally employed for source location. AE source is located by measuring the time delay between two or more AE sensors in the array. Location of AE source requires the knowledge of the velocity of AE signals in the medium under study, which can be obtained by simulating the AE sources at known locations within the medium.

In the present study, a multi channel AE system has been employed for detection and location of partial discharge (PD) or corona sources. PD sources were simulated in transformer insulation medium by energizing sharp metallic needles positioned at known locations. Velocity of AE PD signals in transformer oil medium was determined from the value of time delay in receiving AE PD signals by different sensors. The (x, y, z) co-ordinates of the PD source, i.e. the needle tip, were estimated with the help of 3D location software. The estimated coordinates of the PD source were compared with the actual coordinates to verify the accuracy of estimation. This paper discusses the methodology for estimating the propagation velocity of AE PD signals in transformer oil medium and 3D location of single and three sources simulated in transformer oil medium. The accuracy of location results is also discussed.

6. Performance of Polymeric Insulators under Accelerated Ageing under AC & DC Voltages

N. Vasudev, K.N. Ravi, P. Krishna Murthy and Channakeshava

The performance of insulator for AC and DC voltages is of great practical importance as the insulators can be used with both types of voltages. In view of the many advantages of composite (polymeric) insulators, extensive experimental and analytical investigations have been carried out in the present study on the ageing characteristics of these insulators. Inclined plane tracking and erosion tests, as well as the long term ageing tests, were conducted on samples of polymeric insulator materials. It has been possible to conclude from the above experiments that positive polarity DC is more severe for polymeric material compared to negative polarity DC and AC voltages. The surface degradation of the material was diagonised by hydrophobicity measurement and leakage current analysis. Analytical techniques such as x-ray Diffraction, Energy Dispersion x-ray have been used to analyze the material deterioration. Thermo graviometric analysis and Differen tial scanning calorimeter tests were also used to study the fi ller material content in the polymer.


7. Modelling Water Treeing in XLPE Insulation using Electric Field Concepts

S. Ganga, S.N. Moorching and S. Sridhar

A methodology to model water treeing in XLPE insulation by using electric fi eld, elastic deformation due to pressure build up inside void and probability concepts has been developed. Tree patterns have been numerically simulated considering point-plane electrode geometry in XLPE insulation. The strategy of modelling is verifi ed by comparing fractal dimensions of simulated and experimentally generated tree patterns. The current study revealed, that presence of void fi lled with moisture is less harmful to presence of a metallic particle of same dimension and also the growth of bow tie tree terminates after it develops to a fi nite size. Depending upon the type of defects such as semi conducting particle or void fi lled with air etc, that is present in the insulation, further structure of the prebreakdown channel resembled electrical.

8. Corrosion of all Aluminium Alloy Stranded Conductors-A Case Study

Ramakrishna and S. Seetharamu

Aluminium conductor Steel reinforced (ACSR) material has been in use since the beginning of20]pl century for transmission and distribution of electrical energy. All over the world ACSR gained acceptance and is still being used. All Aluminium Alloy Conductors (AAAC) made of Al-Mg-Si alloy, fi rst introduced in France gained popularity because of its higher strength compared to EC grade Aluminium of equivalent size, less weight, higher corrosion resistance and non-magnetic nature compared to ACSR. Over the years different combinations of Al, Mg, Si, have been adopted to meet the desired strength and conductivity. The fi rst alloys introduced were non-heat treatable. Later, heat treatable and artifi cially aged conductors with still higher strength were introduced.

The application of AAAC has been widely accepted in India. However, instances of corrosion damage are reported despite the fact that all the quality norms are followed for the procurement of conductors. This paper deals with various aspects of corrosion damage occurred to the conductors. The damage occurred to the conductors have been investigated from the point of view of its composition, manufacturing process, strength, resistance to corrosion and method of storage.

9. Ferroelectric Nanomaterials Through Mechano-Chemical Processing

S. Vynatheya, S. Seetharamu and Parvati Ramaswamy

Ferroelectric perovskite powders pertaining to various oxides were prepared by using mechano-chemical processing followed by heating at low temperatures (200°C–400°C). The complete process yielded nano (~ 50 nm) to submicron (up to 0.3 μm) sized powders of well formed compound indicating complete formation of the desired phase. It has been shown that mechano-chemical activation substantially increases the solid - state chemical reactions at the milling temperatures. During milling, the reaction zones have not only increased as the particle and grain sizes have decreased, product phases have also formed at low temperatures with smaller amount of external energy compared to conventional processing methods.


10. Energy Services in International Trade: Implications for a Developing Country like India

B.S.K. Naidu

Energy must be available, accessible and affordable. But let us remind ourselves that it varies amongst countries and regions and in spite of the growing awareness of environmental implications, the 20th century has ended with the world’s commercial energy mix as Fossil fuels - 85 per cent, Hydro - 9 per cent, Nuclear - 4 per cent, New renewables - 2 per cent. Nearly two billion people (one third of the world’s population) have no access to modern commercial energy forms such as electricity and oil.

11. Combustion Characterization of a Pulverized Coal 210 MW Boiler through Computational Fluid Dynamics Approach

V. Saravanan, Ramakrishna and S. Seetharamu

This study consists of the numerical simulation (based on commercial CFD code) of the fl ow and combustion processes that take place in the furnace of a 210 MW pulverized coal utility boiler. The modeling has been done for various conditions like coal mass fl ow and particle size distribution from different burner levels. The modeling has also been carried out for different burner tilt angles. The effects of these conditions in terms of unburnts, heat fl ux distribution, emissions, actual heat energy utilized in the boiler, heat loss in terms of unburnts and heat carried away by fl ue gas have been brought out in this paper.

12. Effect of Ash on the Effi ciency and Capacity of Coal Fired Thermal Power plants

M. Siddhartha Bhatt

This paper reports the effect of ash content in raw coal on the energy performance of coal fi red thermal power plants of capacity range 30-500 MW. It also gives the extent of capacity reduction in equipment due to fi ring of coals with higher ash contents.

The effects of variation of ash in coal from 6% (taken as standard) up to 75% (extreme) on component performance are studied and overall unit performance is quantifi ed based on experimental data and performance simulation. When the ash content increases from 6% to 57% and above, the effects on the system (without fuel oil support) are: (a) effi ciency of boiler fans drop by 22-27%, (b) drum mills show an increase in SEC of 115% while ball-race mills and bowl mills show an increase in SEC of 30%, (c) ID, FD and PA fans shown an increase in SEC of around 30%, 6-14% and 2-7% respectively, (d) the gross and net overall effi ciencies are reduced to 77% and 66% of their original values, (e) ratio of the specifi c fuel consumption at a given ash content to that at standard ash of 6% increases from 1 to 10, and (f) SFCgross increases from 0.35 to 3.0.

When the ash content of coal goes beyond 57%, limitations in combustion space and fl ow arise and beyond this the unit has to be operated only at part load. When the ash in coal exceeds 75%, its UHV is reduced to zero.


13. Life Assessment of Super Heater and Reheater Tubes through Steam Side Oxide Scale Measurements-CPRI Experience

R.K. Kumar, V.N. Nagaraja Rao and S. Seetharamu

High temperature pressure parts of boilers where in creep is the major damage mechanism, are required to be assessed periodically (after 100000 hrs) for remaining life. Creep life estimation could be made by destructive and non destructive techniques. This paper highlights the use of ultrasonic technique for assessment of creep life of SH/RH tubes by in-situ steam side oxide scale measurement. The scope for future studies are also given in the paper.

14. Turn Fault Characteristics Of Transformer Using Transfer Function Method

Pradeep M. Nirgude, B. Gunasekaran, Channakeshava, A.D. Rajkumar and B.P. Singh

The paper presents the transfer function method used to study the turn fault characteristics behavior of a 100 MVA, 220/66/11 kV transformer. The whole transformer is modeled by subdividing into 44 sections and represented by self-inductance, mutual inductance and capacitance parameters. The current in the neutral is computed by solving the network for applied impulse voltage. The transfer function is obtained for various turn faults simulated by reducing the number of turns in the electrical data for a given section. The location of the turn faults along the height of the winding is varied to study the characteristics behavior of the transformer by computing transfer function. Details of modeling, simulation of turn faults, computation of neutral current, transfer function are presented in the paper. The effect of turn fault on the characteristic changes in the transfer function of the transformer is presented and discussed.

15. Seismic Testing of a Bamboo Based Building System

R. Ramesh Babu, K.B. Manjunath, Prabhakar Hegde, R. Panneer Selvam, Paul Follet, H.N. Jagadeesh and H.G. Reddy

Bamboo grows in abundance in the earth’s subtropical and tropical zones, where the majority of earthquake hazards occur regularly. Bamboo is gaining in popularity as an earthquake-mitigating material because engineers are beginning to understand its structural properties. A research project has been taken up to investigate the practical use of bamboo in inexpensive, earthquake-resistant structures. Seismic tests were carried out on a full scale one room bamboo house using triaxial shaker system to evaluate its adequacy in resisting earthquake loads and to study its performance during earthquake.

Vol. 2, No. 1, March 2005

ABSTRACT LIST

THE JOURNAL OF CPRI - Vol. 2, No. 1, March 2005

1. Feasibility Studies on Upgradation of Existing Transmission Lines - Mechanical Aspects

M. Selvaraj and P. Muniyappa

Increase in demand for electrical power necessitates enhancement of power transmission capability of the existing lines. This increased demand for power can be met by up-rating and/or up-grading, the existing lines under specifi c constraints. In this paper, the work done by CPRI for up-grading a few existing transmission lines into possible higher voltages for power utilities are discussed.

2. Towards Bench Marking of Gross Unit Heat Rate in Coal Fired Thermal Power Stations - A Rational Approach

M. Siddhartha Bhatt and B.H. Narayana

The heat rate (HR) is the coupling factor or the transfer function relating the coal consumption to the electric generation. Presently there are knowledge gaps in the designing of energy performance indices and evaluating the performance of operating thermal power units using these. This paper reports a new method for estimation of gross unit HR and thereafter the HRs of the station and the generating company (GENCO) by a concept called as rational HR. The rational HR, which forms the basis for performance standards, is arrived at by calculating the design HR and adding the deviations on various allowable counts to the design value. The HR so arrived from this procedure can be used for the purpose of evolving a standard HR and ultimately for benchmarking of HR depending on age, operating, etc., for setting up effi ciency standards. For a typical 210 MW unit, typically, a deviation of 281 kcal/kWh can be allowed from the design gross unit HR for fi xing the standard bench mark. Another conclusion from the study is that the calorifi c value (CV) of the coal should be on As Fired Basis (AFB) and not on Air Dried Basis (ADB).

3. Evaluation of Structural Properties of Porcelain Materials Using NDE Methods

P. Sampathkumaran, S. Vynatheya, R.K. Kumar, S. Seetharamu, Vishwas I. Bhat and K.R. Hebbar

Porcelain products have gained popularity over the years in a variety of fi eld applications ranging from electrical insulation to dinnerware. The percentage of a-alumina and α-quartz in porcelain material is said to have signifi cant effect on its structural properties. In this work, three grades of porcelain (ceramic) samples with varying alumina and quartz contents have been studied with a view to correlate their material constants with composition. Owing to the anisotropy and brittleness; the evaluation of elastic properties of such materials through conventional technique is quite involved and results in a larger scatter. This work reports the evaluation of material constants by the impulse excitation (sonic) method. To verify the accuracy of the method, tests were carried out on a standard aluminum sample, and the results are compared with the values given in literature as well as the values found by the ultrasonic method. The poisson’s ratio has been estimated by simulating the natural frequencies by fi nite element analysis (FEA) and selecting the value having least mean square error in comparison with the experimental value. It is found that an increase in α-alumina and decrease in α-quartz lead to a considerable improvement in the elastic constant.


4. Dissolved Gas Analysis of Transformer Oil using Novel Multiple Gas Extraction System

R. Panneer Selvam, D. Ravindra, H.C. Keshavamurthy and G.R. Viswanath

Dissolved Gas Analysis (DGA) is the technique used to fi nd the internal faults in the transformers at the incipient stage. Since faults are detected at the initial stage, repair work can be planned at a convenient time based on the severity of faults and major failure of transformers can be avoided. This in turn results in improving the reliability of power supply. Liquid Dielectrics Laboratory (LDL) of Central Power Research Institute (CPRI) is pioneer in DGA technique involved in monitoring of transformers internal condition for the past two decades. LDL monitors more than 1000 transformers every year for its internal condition. New multiple gas extraction system was designed and fabricated at LDL, which works on the topler pump principle. This Novel Multiple Gas Extraction Apparatus is highly effi cient system which can extract 98% of dissolved gases in transformer oil. Also Multiple Extraction Apparatus is simple, compact, easy to operate and requires less mercury.

5. Sliding Wear Behaviour of Glass-Epoxy Composite System

P. Thomas, P. Sampathkumaran, R.K. Kumar and S. Seetharamu

Inexpensive electrical (E) grade fi berglass composites are in use today in a wide variety of applications from consumer products such as fi berglass boats to aerospace components. Fiber composites possess high strength to weight and stiffness to weight ratios. In the present work, the G-E composites were fabricated using a hand lay up technique hy stacking two different fabrics in alternate sequences. The slide wear loss measurements were carried out using a pin on disc set up for four different sliding distances and loads with a view to monitor the effect of these parameters on the wear loss. Differing responses in the wear behaviour were noticed with respect to the load and sliding distance parameters employed for the G-E system. These wear data were well supported by Scanning Electron Microscopic (SEM) pictures.

6. Pyridine based Heterocycles as Possible Curing Agents for Epoxy Resin System

P. V. Reddy, Sakuntala Samuelson and N. M. Nanje Gowda

Pyridine based heterocycles 2-(4-pyridyl) benzimidazole, 2,6-bis (benzimidazol-2-yl) pyridine, dichloro di[2,6-bis(2-benzimidazyl)pyridine]nickel(II), and dichloro di[2,6-bis(2-benzimidazyl)pyridine] cobalt(II) have been synthesized, characterized and evaluated for possible curing of anhydride curable epoxy resin system. It appears that the rate of curing is found to increase with enhanced concentrations of these heterocycles. There is an appreciable reduction in the cure gel time with the enhanced concentration of heterocycles. Kinetic studies based on thermo analytical techniques reveal that the cure times of these epoxy resin systems decrease with increase in temperature and also with enhanced concentration. The values obtained are comparable to those systems with commercial accelerator. It is also observed that the electrical properties of the cured epoxy system in presence of the heterocycles show lower loss factor values than that corresponding to metal complexes.


7. Effect of Surface Coatings on Erosion Behaviour of Hydroturbine Steels

D.B. Goel, Neeraj K Sharma, Jadav Jhansi Bai and Navneet Arora

Investigations have been carried out on the erosion behaviour of surface coated steels which fi nd application in the fabrication of under water parts in hydroelectric projects. Three different grades of austenitic stainless steels (AISI 304, 26/10 and 21-4-N) and one grade of martensitic steel (13/4) have been used as substrate materials. Three types of coating substances, viz. (i) WC-Co-Cr, (ii) Cr3C2-NiCr and (iii) A1203 have been coated on steel substrates using (i) Detonation Gun and (ii) Plasma Spray techniques. A sand blast type test rig has been designed and fabricated for conducting erosion tests on substrates and surface coated specimens. The erosion behaviour has been analyzed on the basis of met alio graphic examination (optical and scanning electron microscopic) and other parameters like hardness and porosity contents in surface coatings.

8. Status and Future Directions of Electric Power Industry Restructuring in India

S.N. Singh and S.C. Srivastava

Power industry restructuring, around the world, has strongly infl uenced the Asian power industry as well. Restructuring of Indian power industry introduced a limited level of competition since 1991 at generation level by allowing participation of Independent Power Producers (IPPs). The new Electricity Act 2003 provides a framework for allowing competition in stages at different levels. It is felt that the prevailing condition in the country is good only for wholesale competition at present and not for the retail competition. This paper analyzes the current status of Indian power sector and suggests a possible model for establishing competitive electricity market in the country.

9. Selection of Features for Security Evaluation of Power System using ANN

K.R. Niazi, C.M. Arora and S.L. Surana

This paper presents an Artifi cial Neural Network (ANN) based method for on-line security evaluation of power systems. A large number of features (variables) characterize a given power system. The ANN can not be trained with complete set of power system variables (features) due to high dimensionality; therefore, feature selection is necessary to make the approach feasible. This paper uses a divergence based feature selection algorithm to select best possible size of neural training features. A comparison of different feature selection methods is presented. The effect of number of features and size of training set on the performance of ANN has also been investigated. The method has been applied on an IEEE test system and the results demonstrate the potential of the proposed method for on-line security evaluation of power systems even under changing topological conditions.


10. Power System Stabilizers in Power Systems

P.V. Bala Subramanyam

The Power System Stabilizer (PSS) is an optional control that is part of the excitation system for generator control. The PSS acts to modulate the generator fi eld voltage to damp electrical power-speed oscillations. It is desirable to ensure that the generator controls are equipped to support transmission system reliability by enhancing the excitation controls. The Power System Stabilizer (PSS) provides supplementary control that improves dynamic stability by increasing damping of power swing oscillations. Excitation systems with high gain and fast response times greatly aid transient stability (synchronizing torque), but at the same time tend to reduce small signal stability (damping torque). The main objective of the PSS is to increase damping of generator rotor angle swings, which can occur in a broad range of frequencies in the power system.

11. Facts about Energy Saving in Lighting

H R Sreenatha Rao & M S Divekar

For conventional lighting for many decades, incandescent bulbs have been used widely. The incandescent lamp was fi rst developed by the great scientist Thomas Alva Edison. Fluorescent lamp (FL) or popularly known as Tube light (TL) was developed much later. Subsequently Compact Fluorescent lamps (CFL) were developed. Both these are low pressure gas discharge tubes. For the purpose of this article, the discussion will be restricted to these three varieties of lamps only, which are used for general lighting for normal use. CFL is nothing but a FL bent in some form. The very purpose of developing a CFL was to see that it replaces an incandescent lamp, particularly where space is a constraint in existing fi ttings. (It is extremely important to know this rider). Hence, where space is not a constraint FL is far more effi cient than CFL!!! Hence in all new applications FL is to be preferred to CFL, if one is particularly concerned about energy effi ciency, Green environ ment. The purpose of this article is to explain this fact.

12. Computational Models for Residual Creep Life Prediction of Power Plant Components

G.S. Grewal and A.K. Singh

In high temperature steam tubing in power plants, one mechanism by which a signifi cant temperature rise can occur is by the growth of a thermally insulating oxide fi lm on its steam side surface. In the present paper, an elegantly simple and computationally effi cient technique is presented for predicting the residual creep life of steel components subjected to continual steam side oxide fi lm growth. Similarly, fabrication of high temperature power plant components involves extensive use of welding as the fabrication process of choice. Naturally, issues related to the creep life of weldments have to be seriously addressed for safe & continual operation of the welded plant component. Unfortunately, a typical weldment in an engineering structure is a zone of complex microstructural gradation comprising of a number of distinct sub-zones with distinct meso-scale and micro-scale morphology of the phases and (even) chemistry and its creep life prediction presents considerable challenges. The present paper presents a stochastic algorithm, which can be used for developing experimental creep-cavitation intensity versus residual life correlations for welded structures. Apart from estimates of the residual life in a mean fi eld sense, the model can be used for predicting the reliability of the plant component in a rigorous probabilistic setting.


13. Assessment of Strength of Indian Transmission System

Mata Prasad FNAE

The growth of power generation in India since 1947 appear to be quite satisfactory rising from less than 1400 MW to 108,000 MW keeping in view the resources made available. The generation expansion however has so far not been able to meet the load demand with the result that the power shortage has been around 10%. The Five Year Plans laid emphasis on generation expansion at the rate of about 45–50,000 MW in the fi ve year plan period aiming for generation expansion at the rate of 10,000 MW per year. The achievement has been just fi fty percent of what was planned specially in the last two fi ve year Plan period.

Vol. 2, No. 2, September 2005

ABSTRACT LIST

THE JOURNAL OF CPRI - Vol. 2, No. 2, September 2005

1. Fuzzy Logic Approach for Solving Unit Commitment Problem in Utility System

S. Chenthur Pandian, K. Duraiswamy and C. Christober Asir Rajan

Unit Commitment (UC) in power systems refers to the optimization problems for determining the ON/OFF states of generating units that minimize the operating cost for a given time. In this paper; Load Capacity of Generators (LCG), Fuel Cost (FC) and Start-Up Cost (SUP) are taken as fuzzy inputs and the Production Cost (PRC) is taken as an output. The input variable LCG has been divided into fi ve triangular membership functions. They are Low, Below Average, Average, Above Average and High. The other two input variables FC and SUP have been divided into three triangular membership functions. They are Low, Medium and High. The Production Cost (PRC) as an output has been divided into fi ve triangular membership functions. They are Low, Below Average, Average, Above Average and High. Case studies have been performed for State Electricity System (SES) which is known as utility system in this paper. By implementing fuzzy logic the production cost is found out. These values are compared with the Production Cost of conventional Dynamic Programming (DP). It is observed that the fuzzy based production cost is economical than the conventional DP method. Practical calculation and results are taken for simulation and the simulation has been performed by using the developed software in MATLAB package.

2. Fretting Wear and Fretting Fatigue Failures in Power Plant Components: A Review

Aravind Vadiraj and M. Kamaraj

Fretting damage is observed when two mating bodies under contact pressure experience micron level tangential relative motion. Both fretting wear and fretting fatigue induce damage causing premature degradation of the materials. Power plant components have shown failures due to fretting induced damage. This article gives details about the possible locations of fretting damage, different materials used in power generation machinery, failure mechanisms and prevention measures for fretting wear and fretting fatigue failures in power plant components.

3. Multi-machine Wind Diesel Power System with a Superconducting Magnetic Energy Storage Unit at the Load Bus

Shameem Ahmad Lone and Mairaj ud-din Mufti

Wind diesel power systems are characterized by low inertia, low damping and poor reactive power support. These systems are, therefore, very prone to wind power variation, load disturbances and other perturbations. A short-term energy storage unit is generally required to achieve prescribed power quality levels in these systems. In this paper, installation of a Superconducting Magnetic Energy Storage (SMES) unit at the load bus of such a system is proposed. A control strategy based on fuzzy logic is used to modulate the exchange of real and reactive powers between the load bus and the SMES unit in four quadrants of P-Q plane. The effectiveness of the SMES unit is investigated for various case studies using simulation studies.


4. Solar Cooling Systems: An Overview

G.S.V.L. Narasimham and M.V. Krishna Murthy

Utilisation of solar energy for the production of cold by adapting different techniques is discussed. For the cases of vapour compression, vapour absorption, vapour jet and dehumidifi cation-humidifi cation systems, the various aspects such as state of the art, description of typical systems, performance characteristics and design considerations are discussed taking into account the suitability and limitations associated with solar energy collection and storage devices. A comparative study of the different refrigeration systems suitable for solar energy applications is made.

5. Application of Charge Simulation Method (CSM) and Artifi cial Neural Network (ANN) in determining Corona Power Loss

N. Roy, Nabamita Roy and K. Bhattacharya

In this paper, a numerical method has been employed for evaluating the Corona Power Loss (CPL) in a single-phase AC transmission line. In this method, the emission of ions is considered to take place from the wire when the fi eld on the wire surface exceeds the onset value. The ion emission stops when the system voltage reaches the corona ending value. Both the charges of the conductor and the space charges are simulated by discrete line charges. The Charge Simulation Method (CSM) has been applied to compute the charge emission from the coronating wire during corona periods over, both the positive and negative, half cycles. The simulated line charges are displaced away from and back to the wire by the prevailing AC fi eld, as computed by the CSM, with subsequent recombination between the outgoing and returning line charges of opposite polarities. The ion emission is considered to reach a steady state after several AC cycles and the CPL is computed when the ion emission reaches a steady state. The computed CPL agrees well with the one measured experimentally. The computed values of CPL and the corresponding applied voltages are fed to an Artifi cial Neural Network (ANN) for training, as the output and input vectors, respectively. After successful completion of the training, CPL corresponding to any voltage lying within the range of input pattern vector is obtained from the ANN. This corona power obtained from ANN is then compared with the value obtained using CSM and the error is well within the limit.


6. Infl uence of Moisture Absorption on Electrical Characteristics of Glass-Epoxy Polymer Composite System

P. Thomas, P. Sampathkumaran, S. Seetharamu, K. Dwarakanath and Kishore

The Fibre Reinforced Polymer (FRP) composites, which are being increasingly used in electrical insulation, should withstand electrical stresses under moist environment. The composites get deteriorated due to the moisture absorption in the working environment. During the moisture absorption process, water ingression into the interior including the polymer reinforcement interface region occurs causing degradation. This signifi cantly contributes to the deterioration of electrical characteristics. To study these, composites having three different volume fractions of fi bres were fabricated using the hand lay up technique by stacking two different fabrics, chiefl y, Woven Roving (WR) and Chopped Strand Mat (CSM). For one set, the top layer was made of CSM and the bottom WR (Composite 1). For the next two, CSM layers were both at the top and bottom while the number of WR that followed these cover layers was either two, in one case, (Composite 2), or, three in the other (Composite 3). The dielectric dissipation factor, dielectric constant and insulation resistance measurements were carried out on these composites at room temperature and after subjecting to water absorption up to 96 h. The weight gain for all three types of composites show a linear increasing trend up to 72 h and thereafter a trend for saturation sets in. Further, it is seen that the dielectric dissipation factor and dielectric constant of the composites increase with increase in the water absorption duration and correspondingly the insulation resistance shows a deteriorating trend. Among the three composites studied, Composite 2 having highest fi bre content and, hence, the least matrix content shows better performance compared to composites 1 and 3.

7. Transformer Diagnostic Testing by SFRA

Ashok Kumar Yadav and Subhash C. Taneja

High short circuit currents can lead to deformations and displacements of the transformer windings due to mechanical forces. The paper discusses SFRA — a modern diagnostic method which identifi es such pre-damaged power transformers which have better sensitivity towards changes in the winding geometry. Changes in the geometric confi guration alter the impedance network, and in turn alter the transfer function. This enables a wide range of failure modes to be identifi ed. SFRA analysis of post-failure of transformers without oil, bushing and previous complimentary test results is being discussed.


8. Mechanical Property Evaluation of Polyurethane based Epoxy and Polyester Alloys

Rajshekhar Algood, Prashanth T, S C Sharma and Syed Akeel Ahmed

Polymers have extended the horizon of engineering materials beyond the realm of natural combinations and into the realm of man-made ones. Polyurethane polymers formed by interpenetrating two or more sorts of cross-linked polymers through physical or chemical methods have gained more and more attention in recent years. In the present investigation, polyurethane alloys were prepared by volumetric mixing of the constituent resins. Polyurethane-polyester alloys (PPA) and polyurethane-epoxy alloys (PEA) were prepared, with polyester/epoxy varying from 10 to 20-volume fraction in steps of 5-volume fraction. The polymerization processes were traced through morphology. Mechanical properties of the alloy systems were studied through tensile strength, hardness and SEM studies. The results of the study indicated that as the polyester or epoxy content in the alloys was increased; there was a remarkable increase in the Young’s modulus, ultimate tensile strength and hardness. The PPA specimens showed superior properties to that of PEA and polyurethane specimens. This study brings out the mechanical property evaluation of the above mentioned polymers. It is thereby intended to utilize these results further by alloying the best out of the three polymers (Polyurethane) with E-Glass, suitable to be cast into Braided Tubes used extensively for space applications.

9. Recent trends in High Voltage Engineering Research

A.K. Tripathy and K.N. Ravi

Higher and higher voltage for power transmission has been a fascinating subject of research after the advantages of EHV transmission was realized nearly a century back. Centres for EHV and UHV research in the early seventies and eighties were the IREQ of Canada, AEP of USA, CESI of Italy, The BPA of USA, ASEA of Sweden, SIEMENS of Germany and the High Voltage Research Centers at St. Petersburg, Russia. UHV levels up to 1200 kV and HVDC Voltage up to +750 kV were explored and the behaviour was studied.

The research on UHV could not be supported for long because it was realized that for UHV lines carrying beyond 2000 to 3000 MW of power, reliability was a major question. The teething problems with early 765 kV AEP and HQI lines, particularly the reactive power problems and switching O/V problems were deterrent to introduction of very high voltage in a weak grid. The reliability of the lines depended on good insulators, tower design, arrester protection, high temperature conductors which were not perfected at those times.

All over the world, 345kV, 400 kV, 500 kV and 765 kV emerged as standard voltages in AC transmission and +500 kV and +600 kV for DC transmission. As equipments of proven design and reliability were produced by manufacturers, these voltage levels were stabilized.

The interest in introducing +800 kV DC and 1000 kV AC has again surfaced as the system is growing, and level of confi dence in +600kV DC and 765kV AC is increasing.

In this paper, an attempt has been made to study the major research areas in High Voltage discipline. The source of information is publication in journals and available information from suppliers, test houses and institutes.


ABSTRACT LIST


1. Development of a New Technique for Measurement of Coal Flow

M. Sidhartha Bhatt and B.H. Narayana

This paper reports the development of two novel products—a coal fl ow simulator and an instrument for coal fl ow measurement.

Uniform pulverized coal fl ow is simulated in a horizontal pipe of 200 mm diameter and 2000 mm length with a capacity 50-300 kg/h at an air to fuel ratio of 1.5-2.5 kg of air/kg of fuel with a maximum of 20% moisture. Coal is fed from a hopper and the fl ow is simulated in a tube. The calibrated coal fl ow is achieved through a vibratory feeder with a convergent-divergent nozzle which is pneumatically activated from a compressed air source. The simulator is isolated from vibrations and fl ow measurement/visual imaging is possible through air-curtained ports. The loss of coal to the environment at the end of the simulation zone is less than 0.05%. The non-reactive, non-mixing type, PC compatible portable instrument for measurement of pulverized coal fl ow uses a new sensing tool-laser through laser beam interception for fl ow through circular pipes of 0.3-0.5 m diameter. It is capable of measuring pulverized coal fl ows of the order of 0-150 kg/h (for a pipe of 200 mm diameter) in the range of 0-5000 kg/m2/h. The laser-through beam sensor is mounted across the fl ow without contact with the coal. The opacity offered by the pulverized coal fl owing in the pipe to the radiation emitted by the transmitter is proportionate to its mass fl ow. The receiver induces a voltage proportional to the intensity of residual light received which is calibrated based on the mass fl ow rate. The induced voltage is stepped down, processed, digitized and acquired through Rs. 485 data protocol. The standard coal that can be measured is sized at 70% of the mass below 75 μm size. The normal primary air to fuel ratio is around 1.5-2.2 kg of air/kg of coal. The instrument is insensitive to moisture contents upto 10%. For moisture contents above 10% and for fi neness and air/fuel ratio different from the above, calibration of the instrument is required. The instrument has an accuracy of 0.5% and the response time is 0.5 ms for standard coal. It operates on a power source of 230 V AC (100 W) and is useful for fi eld applications as a portable instrument (0.5 m x 0.5 m x 0.5 m).

2. System Studies of Grid Disturbances Encountered in Kashmir Valley Power System During Islanding Operation Subsequent to Link Failure with Northern Regional Grid in February, 2005

N.A. Laway, Wasim Aziz Shah and Ghulam Nabi Shah

The Northern Regional (NR) Grid consists of generation and transmission power utilities of the states of Jammu and Kashmir, Punjab, Himachal Pradesh, Haryana, Rajasthan, Delhi and Uttaranchal, and the central utilities viz Powergrid, NHPC, NTPC. The Regional Electricity Board of J & K, Power Development Department (PDD) and Power Grid experienced several major grid disturbances in the recent past resulting in cascade tripping of 220 kV lines and generating units. This resulted in separation of grid into several isolated parts with disruption of power supply. This paper deals with the analysis of the grid disturbance that occurred on 12 Feburary, 2005. In this paper, main emphasis is given to abnormal behaviour of generating units at Uri-I (NHPC) generating station at Uri, Baramulla (Kashmir).


3. Simulation and Comparison of the STC (Synthetic Test Circuit) for thyristor valves for HVDC by the software PSCAD

Zhou Huigao, Xu Fan, Hu Zhilong, Huang Chao, Zheng Jun, Li Yanming

In recent years, HVDC technology has been developing very fast with the increasing demand of electric power in China. It is very important to build up a test circuit for operational test of thyristors in order to ensure the safety and reliability of HVDC system. Today there are only two test laboratories in the world which are capable of undertaking the synthetic test—ABB in Sweden and Siemens in Germany. After comparing and studying the two circuits, a new model is set up for analysis and simulation, and all the test duties which are required in IEC 60700-1 are successfully achieved by the use of PSCAD.

In this paper, the principle of the circuit and the simulation results are presented. It is very helpful in building up the STC of China on its own.

4. Fuzzy Identifi cation and Modeling of an Intelligent Controller for Adaptive Control of Reactive Power in a Utility System Using ANFIS

S. Thangavel, V. Palanisamy, K. Duraiswamy and S. Chenthur Pandian

Modern power systems tend to be very complex not only due to increasing demand for quality power, but also on account of extensive interconnection and increasing dependence on control for utilization of power with optimum losses and cost. Either conventional controller or intelligent controller can be used to get the adaptiveness in the parameters of the system considered. As the conventional controllers are non-interactive and cannot compensate for parameter variation, control engineers are moving to intelligent controllers for adaptive control. Since any power system does not have proper modeling and shows non-linear behaviour, it requires a continuous expert knowledge for its control. Hence fuzzy logic controllers are the most suitable intelligent tools for the adaptiveness of the power system. Here the Adaptive Neuro Fuzzy Inference System (ANFIS) is used to obtain the adaptiveness in the system. The adaptive control of reactive power in a utility system has been justifi ed in this paper.

5. Performance Analysis of Unifi ed Power Flow Controller using Fuzzy-PI Control

S. K. Srivastava, K.G. Upadhyay and S.N. Singh

The Unifi ed Power Flow Controller (UPFC) is one of the most versatile FACTS devices that has unique capability of independently controlling the real and reactive power fl ows, in addition to regulating the system bus voltage. This paper presents performance analysis of Unifi ed Power Flow Controller based on the two-axis theory. Based on this analysis a new Fuzzy-PI controller has been proposed to improve the system performance. The controller rules are structured depending upon the relationship between series inserted voltage arid the desired changes in real/reactive power fl ow in the power system. The effects of different controllers along with parameters of series transformer and transmission line have been investigated through developed control block model in SIMULINK. The effectiveness of the proposed scheme is demonstrated by case studies.


6. Compatibilization of Biodegradable Tapioca Starch/LDPE Blends to obtain Products to be used for Short Term Packaging Applications: Dealing with Waste Polyethylene from the Power Sector

R.R.N. Sailaja and S. Seetharamu

LDPE has been blended with plasticized Tapioca Starch (TS) with starch loadings varying from 20% to 50%. As the starch loading increases, the mechanical properties reduce and drop down to nearly 30% of that of neat LDPE. In order to enhance the adhesion between starch and LDPE, itaconic acid (naturally obtained during fermentation of sugars) was grafted onto LDPE to obtain LDPE-g-itaconic acid and used as compatibilizer. Addition of this compatibilizer substantially improved the mechanical properties, especially the tensile strength (at par with that of virgin LDPE) and tensile modulus TS loading of 40%. Scanning electron micrographs of the blend specimens also supported the above observation. Thermo gravimetric analysis was carried out to assess the thermal degradation of blends.

This study aims at a possibility of utilization of post consumer polyethylene waste for producing biodegradable blends.

7. Infl uence of Load on the Friction and Wear Behaviour in Glass-Epoxy Composite Systems

B. Suresha, G. Chandramohan, P. Sampathkumaran, R.K. Kumar, S. Seetharamu and C.H. Sathish

Polymeric composites are steadily gaining importance in recent times for industrial applications and their increase in the use calls for a better understanding of their behaviour under working environments. Friction and wear are considered two important parameters, that govern the tribological behaviour. In this study, the friction and wear characteristics of E-glass-Epoxy (G-E) and graphite fi ller of two different levels in G-E composites were experimentally investigated using Pin-on-Disc setup at varied loads and sliding velocities. From this investigation, it is found that 7.5 wt % graphite fi lled G-E composite system shows least coeffi cient of friction and highest wear resistance compared to the plain G-E composite system irrespective of the load/speed adopted. Further, this paper highlights the Scanning Electron Microscopic (SEM) observations with respect to their wear behaviour for interpretation of the data. The SEM pictures of the highest graphite fi lled sample corroborate the wear data thus complimenting each other.

8. SA based Genetic Algorithm for Reactive Power Optimization

B. Bhattacharya and S.K. Goswami

Genetic Algorithm (GA) is hybridized with the Simulated Annealing (SA) technique while solving the reactive power optimization problem. This hybrid Genetic Algorithm is used for both optimum planning and dispatch of reactive Var Sources. SA used along with GA for reactive power optimization yields better solution than GA. First a focus zone of the search space is identifi ed by using the SA technique and then Genetic Algorithm (GA) with population initialized around that focus is applied to obtain the optimum.


9. Risk Assessment for Catastrophic Failures in Power Systems

J. Hazra and A.K. Sinha

This paper presents a method for identifying sequences of events (Worms) leading to catastrophic failures of power systems. Chains of events leading to catastrophic failures are identifi ed using two indices (i) Severity Index (ii) Risk Index. The fi rst method considers only the consequences of an event whereas the second one considers the consequence of an event along with the probability of occurrence of that event. Risk index condenses both probability and severity of any event. This paper also considers the probability of hidden failure of exposed lines for calculating the risk index.

10. A New Approach to the Determination of Optimal Sizes and Optimal Locations of SVC Devices for Voltage Profi le Improvement of a Power System

D. Sathaiah, E. Akila and B. Andal

A new systematic method for determination of optimal sizes as well as optimal locations of SVC devices for voltage stability and voltage profi le improvement of a power system is presented. The proposed method is based on static voltage stability criterion using the well-known L-index. The highest value of L-index indicates the most critical bus in the system. The proposed new approach has been tested on IEEE 14-bus test system and IEEE 30-bus test system under different operating conditions. The results are found to be quite satisfactory.

11. Modular Power Supply for Telecom Application (48 V/100 A)

T. Thandapani and R. Arumugam

This paper describes the practical aspects of building modular power supply for telecom application. The latest requirements of the telecom industry calls for high effi cient power supplies capable of handling large input voltage variation. The power supplies are required to produce high input power factor and low input current harmonic distortion. In addition to the above, the power supplies should be of light weight, smaller in dimension and modular in construction.

Although there are lot of papers on Power Factor Correction (PFC) circuits, soft switching converters, Active current sharing circuits, RFI/EMI etc., none or very few papers provide a complete solution for an industrial power supply. In this paper, an attempt is made to provide a complete, economical and a viable solution for building a Telecom power supply which meets or exceeds the requirements of the telecom industry. A three-phase converter using three single-phase modules connected in parallel is discussed. Each single-phase module has an active power factor correction circuit on the front end followed by a high effi cient resonant zero voltage switched DC-DC Converter circuit along with an active current sharing circuit for sharing the current between the modules equally. This current sharing circuit requires only a single wire for communication between the modules.


ABSTRACT LIST


1. Development of a Silicone Composition for High Voltage Insulator Applications

K. Praveen, M.N. Dinesh, P.V. Reddy and N. Vasudev

Silicone rubber and their alloys have good high voltage insulation properties with excellent outdoor usability. The hydrophobicity of the surface is well maintained even in wet conditions as low molecular weight fl uids diffuse out to the surface. In the present work, trihydrated alumina content in the silicone compositions has been varied with other additives and electrical properties namely tracking and erosion, corona and salt-fog were studied. The mechanical properties namely tensile strength, elongation and hardness were evaluated. The Oxidative Induction Time (OIT) test was conducted to determine the oxidative stability of the insulation. The SEM analysis was carried out to study the fi ller distribution in the polymer matrix.

2. Frequency Response Analysis for Detecting Winding Displacement and Deformation in Power Transformers without Reference Fingerprints

Pradeep M. Nirgude, D. Ashokaraju, A.D. Rajkumar and B.P. Singh

The paper presents the results and analysis of the experimental work carried out to apply construction based and type-based approach to interpret Frequency Response Analysis (FRA) measurement data. Infl uence of the tap changer position on the FRA measurements is analyzed. Results of onsite FRA measurements carried out on two identical transformers with an emphasis on the detection of mechanical winding deformation without fi ngerprints are presented and discussed.

3. Application of Hopfi eld Neural Network and Dynamic Programming to Unit Commitment

S. Senthil Kumar and V. Palanisamy

This paper develops a new Dynamic Programming based direct computation Hopfi eld method for solving short term Unit Commitment (UC) problems of thermal generators. The proposed two-step process uses a direct computation Hopfi eld neural network to generate Economic Dispatch (ED). Then using Dynamic Programming (DP), the generator schedule is produced. The method employs a linear input-output model for neurons. Formulations for solving the UC problems are explored. Through the application of these formulations, direct computation instead of iterations for solving the problems becomes possible. However, it has been found that the UC problem cannot be tackled accurately within the framework of the conventional Hopfi eld network. Unlike the usual Hopfi eld methods which select the weighting factors of the energy function by trials, the proposed method determines the corresponding factor using formulation calculation. Hence, it is relatively easy to apply the proposed method. The Neyveli Thermal Power Station (NTPS) unit II in India has been considered as a case study and extensive studies have also been performed for different power systems consisting of 10, 20 and 40 generating units. Numerical results obtained are compared with conventional methods to reach proper unit commitment.


4. Simulation of Availability-based Tariff Mechanism

K.Balaraman and Dr. T. Ananthapadmanabha

Availability-based Tariff (ABT) mechanism is in operation in India from 1st July 2002. The introduction of ABT mechanism has revolutionized the power system operation in India and has opened a new framework for power trading opportunities in the country. This paper provides a mechanism for simulating ABT through a mathematical model. The simulation is carried out for various operating conditions such as average load, light load and peak load conditions. The behaviour of various constituents in the system operation is described.

5. Available Transfer Capability in Competitive Power Market: A Bibliographical Survey

Ashwani Kumar, S.C. Srivastava and S.N. Singh

In the restructured power system, bulk power transactions are restricted by the transmission system security and stability, and it is the responsibility of the system operators (SOs) to control the power transactions and overloading of the transmission network beyond their loading limits. For this, a SO has to update real time index termed as available transfer capability (ATC). This paper addresses an up-to-date bibliographical survey on available transfer capability in the deregulated electricity markets. There are 184 citations referenced in this bibliography. The general electronic websites dealing with the issue of available transfer capability are also listed which are very useful to academicians, utility engineers, policymakers and researchers in competitive electricity markets.

6. A Method for the Determination of Backup/Primary Relay Pairs for Coordination of Directional Relays

N. A. Laway

A novel method is developed to determine the backup/primary relay pairs for use in relay coordination programmes. Backup/primary relay pairs are essential for determining setting of directional overcurrent relays and directional distance relays in a multi-loop complex power transmission system. The algorithm developed is based upon the powerful network scanning capabilities of the linked list type of data structure known as LINKNET. The method developed has been applied to fi nd the coordinating relay pairs for the IEEE 14-bus, the SPC 26-bus, the IEEE 57-bus and the IEEE 118-bus power transmission systems with encouraging results.

7. Life Estimation of Boiler Straight Pipes under Creep and Fatigue Loads

A.R. Veerappan, S. Shanmugam, G. Jayaraman and S. Nagamanickam

Boiler pipe failures are the number one cause of forced outage of power generating units. The principal damage mechanisms in high temperature pressure vessel and piping system is generally creep-fatigue. The creep-fatigue life of straight pipes is estimated based on a transient thermo-mechanical analysis that has been conducted which simulates the past working conditions of straight pipes. The straight pipe is modeled in ANSYS and the model is analysed initially with transient conditions and subsequently with structural constraints. The maximum stress intensity is used to determine the fatigue life fraction of the pipe while the structural analysis is done to determine the creep life fraction of the pipe. A relationship between the life of the pipe under combined creep and fatigue loads and the operating pressure is presented for the material SA335 P22 used for high temperature applications.


8. Optimum Location and Sizing of FACTS Device in Weak AC System with Integration of Wind Farms

B.R. Lakshmikantha, Murugesh Mudaliar, K. Balaraman and R. Nagaraja

Wind energy is perceived to be a clean energy source available in plenty in some pockets of the country. The key issue in harnessing the full potential lies in integrating wind energy into the grid. In the restructured power systems, the transfer capability is presently a critical issue both in the operating and planning stage because of increased interchanges among utilities. This paper highlights the issues in integrating wind energy to the grid and to optimize the location of FACTS devices with the help of L-Index technique. Performance issues related to the dynamic behaviour of wind farms are discussed and the potential interactions between wind turbine generators and compensation equipments are illustrated with simulated examples.

9. Robust Decentralized Control of Power Systems with OLTCs using Markov Jump Parameter Theory

Hemanshu R. Pota, Germane Xavier Athanasius, Li Li and Valery Ugrinovskii

This paper addresses the problem of designing a decentralized control of interconnected power systems, with On Load Tap Changers (OLTCs) and Static Var Compensators (SVCs), under large changes in real and reactive loads that cause signifi cant changes in the model parameters. Large parameter variations are considered as change in the system mode. The decentralised design results in a different linear state-feedback controller for each mode of operation. Adjustments due to small changes in load, about an operating mode, are regulated by these decentralised controllers. The controllers operate locally using the state of the subsystem itself and switch when load on the system increases dramatically. The design is carried out within a large-scale Markov jump parameter systems framework. In this paper, unlike other control schemes, OLTC transformers are used to damp power-angle oscillations. Simulation results are presented to demonstrate the performance of the designed controller.


ABSTRACT LIST


1. Characteristics of Fly Ash Cenospheres and their Effect on Pozzolanic Reactivity of Fly Ash

K Suryanarayana, M Shekhar Kumar, M C Narasimhan and S Seetharamu

Fly ash cenospheres are particles found fl oating in the ash lagoons of coal fi red thermal power plants. The primary characterisation of these particles indicates that they are hollow, lightweight, predominantly spherical and pozzolanic in character. The cenosphere content in fl y ash varies with the power plant depending on various operational parameters, and is generally estimated at 1 % of the total fl y ash generated. It is reported that the percentage of cenospheres increases with the ash content in the coal, and decreases with the concentration of Fe2Or This indicates that Fe2O3 is concentrated in the higher density fraction of fl y ash. The cenospheres contain higher alumina content, but lower iron content as compared to fl y ash. The particle size distribution in cenospheres again varies from plant to plant, and it is observed that a majority of the particle fractions are below 150 fl m. The density of cenospheres is very low as compared to that of fl y ash, which is due to the hollow nature of the particles. The morphology of cenospheres indicates predominantly spherical particles as compared to fl y ash particles. The pozzolanic reactivity of fl y ash generally depends on the amorphous content or glassy mineral content in them. The X-ray diffraction curves of the fl y ash cenospheres are good indicators of the amorphous character present in the pozzolanic material. From XRD analysis results, it has been observed that the cenospheres show higher amorphous character as compared to fl y ash. These results are corroborated by the pozzolanic reactivity tests.

2. Loss Reduction and Voltage Quality Improvement by Connecting Embedded Generator—A Simulation Study by ETAP Software

S Bhattacharjee, S L Deb, A Das and B Das

An embedded generator is connected to an electrical distribution network. This network is the conduit through which it exports the electrical energy that it produces. Since these exports can have a signifi cant effect on the pattern of fl ows in the network, it is important to check that they do not degrade the quality of supply for the other users of the network. The present study shows how an embedded generator can reduce losses in the network. The power fl ow for maximum and minimum load conditions at different power factors with embedded generation has been studied by ETAP software. The study also reveals the optimum condition for obtaining a better voltage profi le and maximum loss reduction with embedded generator.


3. Short-term Electricity Load and Price Forecasting Techniques in Deregulated Electricity Markets: A case study of Ontario Electricity Market

Sanjeev Kumar Aggarwal, L M Saini and Ashwani Kumar

In this paper, an electricity load and price forecasting case study of Ontario electricity market has been presented. Major load and price drivers have been selected after performing correlation analysis to form electricity load and price forecasting models based on a multiple linear regression (MLR) technique. The load forecasting MLR model has been compared with a heuristic technique and it has been proved that the MLR model is superior to the heuristic model. The effect of price on short-term load forecasting has been studied from demand side responsiveness and it has been shown that no major improvement has been observed by taking price as one of the input variables in the load forecasting model. The results of MLR price forecasting model have been compared with the results of a heuristic model and a model developed by Independent Electricity System Operator (IESO) of Ontario electricity market. The MLR model has outperformed both the other models. The model proposed in this paper is easy to implement and requires a lesser amount of data as compared to IESO model. The results of the proposed model are available 24-hours ahead of actual settlement, whereas IESO forecast is available 3-hours ahead only. Thus the proposed model can help the participants to bid effectively in the market.

4. A Novel Method for Solar Water Pumping Promising Considerable Down Sizing and Cost Reduction of PV Panels

Mrityunjaya Kappali and Uday Kumar R Y

The existing practice of water lifting in multi-storied buildings employs Top Floor Storage Method (TFSM). In this method, considerable amounts of water is pumped to unnecessary heights, resulting in energy wastage. This paper proposes a novel scheme “Individual Floor Storage Method (IFSM)” [1] for Solar Photo Voltaic driven Water Pumping System (SPV-WPS) used in multi-storied buildings. Here water is pumped to the required optimum heights, thus avoiding wastage of energy. This means, for a particular quantity of available energy, the amount of water lifted will be more. Hence we fi nd that for a particular quantity of available energy and for a particular amount of water to be lifted, the SPV panel capacity rating needs to be less. The direct consequence of this is a decrease in the initial investment. Thus, as far as SPV-WPS is concerned, the benefi t of IFSM is downsizing of SPV panel and hence the reduced initial cost. This is a signifi cant advantage particularly with respect to SPV-WPS as their main demerit is high initial cost. Therefore employing IFSM for SPV-WPS will go a long way in making them more acceptable to the common man. In this paper, the SPV-WPS proposal is worked out with TFSM as well as IFSM for a two-storied house. It is found from the initial tests that the PV panel peak power requirement is reduced by about 23% and there is a drop of 17.5% in the overall initial cost.


5. A New Control Approach for UPFC-based on State Feedback Technique

G Saravana Ilango, C Nagamani and M Lalit Kumar

This paper reports a new control approach for the Unifi ed Power Flow Controller (UPFC) for enhanced, dynamic and steady state performance-based on state feedback control technique. The results of investigations are presented on the implementation of State feedback control technique in a power transmission system incorporating UPFC. The use of state feedback control for controlling the operation of UPFC has not been reported earlier in the literature. The objective is to achieve effective control of the active and reactive power fl ows in the line, with minimum or zero dynamic interaction between them. A simple two machine power system with a UPFC is used for the study. The system response to the power fl ow commands is investigated and the effectiveness of state feedback control is examined. Reference frame theory based mathematical models are used for analysing the performance of the system in closed loop. Simulations are carried out using MATLAB/SIMULINK. The results indicate an overall improvement in performance with negligible dynamic interaction and zero steady state error, thus validating the proposed control scheme. The proposed approach has a straight forward design and the control law structure is simple.

6. Investigation on Risk of Subsynchronous Resonance for Series Compensated 400 kV Lucknow-Balia Line

J Sreedevi and Sujatha Subhash

This paper presents an analysis of Subsynchronous Resonance (SSR) for series compensated 400kV double circuit Lucknow-Balia line planned in the northern region of India. The power system software SIMPOW in MASTA mode is used for the analysis. The paper demonstrates the usage of an interesting feature present in the software-switching a large power system study between fundamental frequency and instantaneous value mode at any time during the simulation. The SSR consequences for large disturbances have been simulated and the results are presented along with conclusions.

7. Development of a Fast Activating Magnesium-based Solid-State Hydrogen Storing Alloy for Power System Application

G S Grewal, V Shrinet and A K Singh

One of the most attractive methods of storing hydrogen which is rapidly emerging as the technique with the highest degree of commercial promise, is the storage of hydrogen in a chemically bound form as a solid state metallic hydride. In the present work, an effort has been directed for solving the vexing problem of the poor activation characteristics of Magnesium, which typically requires a large number of a-priori “dummy” sequential charging/discharging runs before it becomes possible to react magnesium with hydrogen to its full theoretical capacity. This work has been undertaken in a rigorous Taguchi methodology framework in which systematic combinatoric searches have been made in the ternary magnesium-based alloy system MgxNi1–x–y My, with M being chosen from the set comprising of Al, Cr, Fe and C and an alloy chemistry has been identifi ed with high hydrogen storage capacity along with rapid activation kinetics, which results in the near complete reaction of the magnesium alloy in the initial few charging runs, only. The maximum absorption (formation of hydride) has been measured as 7.4 wt% in about 60 minutes time. This value is about 97% of the theoretical absorption capacity of magnesium.


8. Linear Perturbation-based Simple and Rugged Load Flow

P Acharjee and S K Goswami

A reliable and robust load fl ow method has been developed based on linear perturbation technique. The algorithm is simple. The decoupling properties between the power system quantities have been exploited in developing the load fl ow algorithm. No complicated constraint satisfaction is used, but simple mathematical computations are involved to develop the method. The proposed load fl ow algorithm is rugged, can determine the maximum R/X ratios and the critical loading conditions. The proposed method can fi nd the solution when the conventional load fl ow method fails. The effi ciency and effectiveness of the algorithm has been established showing test results of the different standard and ill-conditioned systems.

9. Coordinated Control of FACTS Controllers

N K Sharma, Arindam Ghosh and R K Varma

This paper discusses the issues of control coordination between SVC and TCSC for multi-machine power system. The parameters of FACTS controllers are obtained using simple and effective root loci technique and modal clamping technique. Subsequently the effects of system loading and level of compensation on the controller parameters are investigated in depth. The results obtained from various studies are further refi ned and validated through step response studies. The results are presented for 9-bus WSCC test system.

10. Supplementary HVDC Controls for Multi-machine System Stability Improvement

V Sandeep Reddy, Dr P S Raju and P V Ramana Rao

This paper deals with the improvement of multi-machine power system stability using supplementary HVDC controls. The current controller model and the line dynamics are considered in the stability analysis. Initially, a combination of control signals required for the HVDC power modulation is determined to improve the power system stability. A fuzzy logic controller is then proposed, which utilises a set of control rules to vary the gains of the above controller and this has been found to improve the system stability further.


ABSTRACT LIST


1. Emerging Applications of Polymers to Energy Sector

Dr J Sundara Rajan

This paper reviews many new and emerging areas of polymer science and its application to power engineering. Electrical and electronic devices make extensive use of polymers in applications ranging from connectors, sockets and switches to bushings, spacers, control panels, supports etc. New areas like electro-active polymers and conductive polymers are fi nding many applications in everyday use. Conductive polymers unlock the potential to improve a variety of items from electronics to electrical engineering. Hydrogen fuel cells hold promise for the future. This paper highlights the importance of developments in polymer science and its relevance to power engineering.

2. Multistress ageing of 28 kV Silicone Rubber Insulators under West and East Coast conditions of the USA

Raji Sundararajan

Long term ageing of polymeric insulators was performed simulating coastal San Francisco and Boston. 28 kV silicone rubber insulators were used for this purpose. The same insulator (design and material) was compared at two different locations (West and East Coasts of the USA—San Francisco and Boston). Weather cycles simulating coastal San Francisco and Boston were developed. The various stresses applied include UV radiation, salt fog to simulate contamination from air-borne particles, clear mist, rain, heat, cold and electrical stress. Data acquisition of the leakage current and cumulative charge is also done by LabVIEW. High voltage divider was used to measure 20 kV using LabVIEW at 2 V. They were aged for thousands of hours and their ageing and degradation were characterised using physical (discolouration, chalking, cracking, hydrophobicity), electrical (surface leakage current, cumulative charge and watts loss) and state-of-the-art material diagnostic techniques such as FTIR, SEM and XPS. Results indicate that silicone rubber insulators withstood these stresses well.

3. Nanostructured Superhydrophobic Coatings

M Farzaneh and D K Sarkar

A short description of the activities and facilities of the CIGELE/INGIVRE Chairs in relation with superhydrophobic and icephobic nanometric coatings has been reported. A brief description of how superhydrophobicity can help mitigate the ice accretion problem on power network equipment and other exposed structures by reducing adhesion of ice to surface has been presented. Basic models namely the Wenzel and Cassie-Baxter models accounting for the contact angle of water on solid surfaces relating to the infl uence of surface roughness on hydrophobicity have been discussed. The CIGELE/INGIVRE research team involved in the development of nanometric materials is actively working on the elaboration of superhydrophobic aluminium surfaces by chemical etching, superhydrophobic copper surfaces by silver nanoparticles, superhydrophobic nanostructured oxides and superhydrophobic nanofi bres. Some of the promising results achieved on superhydrophobicity have been described.


4. Effect of Biocontamination on Polymer Insulators

M N Dinesh, V Krishnan, N Vasudev, K N Ravi, P V Vasudevan Nambudri, K Suryanarayana

Problems due to biocontamination of insulators have been reported in tropical areas of the USA, Sri Lanka, Tanzania, Germany, Sweden, Japan, Mexico, Paraguay and New Zealand. No systematic study has been done to investigate the long term performance of polymeric insulators with biocontamination. When fungi and other microorganisms colonise the surface of an insulator, they impede the drying of the insulator surface and there is a possibility of increased insulator degradation by enzymes secreted by fungal contaminants. Biocontamination causes concern among utility engineers because it is not understood fully. In the present work, algae was allowed to form on silicone rubber insulators. These insulators were then tested under salt fog conditions for a period of 10000 hours and the results are presented.

5. Polymers as Core Materials in Power Engineering

K T Varughese

A brief overview on the growing impact of polymers, in their different forms, playing a critical role in the power transmission and distribution is presented. The selection criteria of conventional and specialty polymers as matrix material in power devices depends on their specifi c properties and the ability to mix with property enhancing additives under passive or active states of electrical stress. Recent advances on nanodielectrics are reviewed. The importance of polymers in switchgears, overhead lines, power cables, transformers and substations are indicated.

6. Water Droplets on Polymeric Surfaces under the Infl uence of High Voltages

Michael G Danikas

In this paper, the problems arising from the application of uniform AC electric fi elds on water droplets, which are on polymer surfaces, are investigated. Polymeric materials such as silicone rubber, PVC and rubber were used. The fl ashover voltage was investigated in terms of water conductivity, polymer surface roughness, droplet volume and droplet position w.r.t. the electrodes. Our research showed that all four aforementioned parameters infl uence the fl ashover voltage.

7. Effect of Cross-linking Systems on the Thermal Behaviour of Nylon copolymer (PA6,66) and Ethylene-Propylene-Diene (EPDM) Rubber Blends and their Kinetic Analysis

Cibi Komalan, K E George, S Thomas, K T Varughese

The thermal stability of nylon 6,66 and ethylene-propylene-diene rubber of dynamically vulcanised blends were studied by thermogravimetric analysis. The composition of nylon copolymer and EPDM was fi xed at 70/30 ratio by weight. The blends were prepared by melt mixing in a Brabender Plasticorder. Thermogravimetric analysis showed that the decomposition proceeds through a single step even though the blends are immiscible and the cross-linked blends were more thermally stable than uncross-linked blends. The kinetic parameter of the degradation process is also studied.


8. Role of the Interface in Improving Surface Degradation Properties of Epoxy Nanocomposites

Parimal Maity and Nandini Gupta

It is widely accepted that the interface between polymer and fi ller particles plays a major role in modifying composite properties, both electrical and otherwise. In this work, we examine the role of the interface in affecting a particular electrical characteristic of the nanocomposite, viz. its resistance to surface degradation. Dielectric materials with improved resistance to surface discharges would help in ensuring better performance and greater reliability of apparatus in service. This paper takes a comprehensive look at the recent work by the authors in this area, and tries to understand the role of the interface in this context. Two essential features emerge. Increase in the interfacial zone at the expense of the bulk polymer imparts better degradation resistant properties to the composite specimen and tailoring of the chemical bond structure at the interface leads to further improvement.

9. Electroluminescence and Space Charge in Nanodielectrics subjected to AC Voltage

S S Bamji, M Abou-Dakka, A Bulinski and L Utracki

Electroluminescence (EL) and Phase Resolved Pulsed Electro-Acoustic (PRPEA) techniques are used to determine charge injection and space charge distribution in insulation subjected to an AC electric fi eld. It is shown that both EL and PRPEA can provide information about the dynamics of charge injection and trapping in solid dielectrics under an AC fi eld. Such techniques are useful in evaluating novel materials, such as nanodielectrics, for use in power apparatus.

10. Fire Safety Assessment of Polymeric Cables and Materials based on Heat Release Rate, Combustion Smoke and Toxicity

B Nageshwar Rao, R Arunjothi, A R Srinivasan, P Rajashekhar and A Sudhindra

This paper presents and discusses heat release measurement, smoke and toxicity data obtained on cables: power, communication, automobile, wires and other materials used for various applications in power plants, petroleum refi neries, metro rail, automobile industries. Fire survival cables intended to maintain electrical integrity under fl aming conditions and fl ame retardant low smoke cables have been evaluated and their performance discussed. Fire safety assessment methods of cables and materials are reviewed and heat release rate, smoke, toxicity data and fl ammability characteristics obtained on materials like polystyrene, cellulosic fi bre materials, upholstery, FRP/GRP laminate and others are discussed. Cushioning materials like polyurethane foam (slab stack, rigid PU, Expandable Graphite foam), thermally densifi ed polyester block have been evaluated for HRR, smoke properties and the results are discussed. The toxicity of these materials evaluated as per NES 713/NCD 1409 are summarised.


11. Electron Beam Cross-linking: An Emerging Technology for Processing Electrical Wires, Cables and Accessories

V V Pattanshetti and J Sundara Rajan

Polymers are extensively used in various power engineering applications for its excellent dielectric and mechanical characteristics. Electron beam technology lends further support for expanding the application of polymers in power engineering. The use of electron beam cross-linking of polymers in preference to the conventional chemical cross-linking processes has several advantages. This paper discusses the advantages of this technology with particular reference to power cable and accessories for termination and joints. The improvements in dielectric, mechanical and thermal characteristics are emphasised to highlight the need for increasing the use of this technology for critical power engineering applications.


ABSTRACT LIST


1. Techno Economic Viability of Hybrid solar (PV) - AC Utility Interfaced Power System for Rural India

S. N. Singh and A .K. Singh

A hybrid solar photovoltaic(PV) - AC utility interfaced power generating system has been developed for domestic use. The system consists of a photovoltaic array (installed on the structure of roof), an intelligent power controller and an inverter with battery as an energy storage device. The system works in such a way that it utilizes maximum power from PV source, convert it into useful AC power for household critical loads. The variation in PV power is supplemented by grid power source integrated with the PV source. The system fi nds wide application in rural sectors where the conventional source of supply has been restricted and further expansion of utility (grid) supply is not possible due to various technical & economic reasons. Thus it saves grid power and reduces the over burdening of power on grid lines . The technology of solar energy conversion into useful AC power through push-pull confi gured transistorised inverter involve PWM strategy which produces a very near sine wave output with minimum THD, leading to a high effi cient system. The system has been designed for 300 W power supply for critical loads. The simulation for generation of PWM pulses and computation of THD value has been carried out. Performance of the system was tested under various abnormal conditions like grid failure, low or no sunshine conditions etc. The system provides optimum use of solar PV power with environmental benefi ts.

2. End-of-Life Evaluation of RTV Coated Porcelain and Glass Insulators Under Pollution Conditions

Shaik Abdul Saleem, J. Amarnath, K. A. Aravind and D. Devendranath

Ageing of Room Temperature Vulcanizing (RTV) silicone rubber coated porcelain and glass disc insulators are reported under combined voltage stress and salt-fog conditions till the loss of hydrophobic properties of RTV coating in an aging chamber. The electrical characteristics are obtained by on-line monitoring of leakage current and material characteristics are analyzed by Energy Dispersive X-Ray (EDX) Analysis. RTV coated glass insulators shattered in to pieces after 2600 hours of aging while RTV coated porcelain after ageing for 4600 hours lost its hydrophobic properties and started behaving like a normal un-coatedporcelain disc insulator.

3. Diagnosis of Inter Turn Fault in the Transformer Winding using Wavelet Based AI Approaches

R.Rajeswari, Lecturer and Dr.N.Kamaraj

In this paper, Wavelet based ANFIS for fi nding inter turn fault of transformer is proposed. The detector uniquely responds to the winding inter turn fault with remarkably high sensitivity. Discrimination of different percentage of winding affected by inter turn fault is provided via ANFIS having an Eight dimensional input vector. This input vector is obtained from features extracted from DWT of inter turn faulty current leaving the transformer phase winding. Training data for ANFIS are generated via a simulation of transformer with inter turn fault using MATLAB. The proposed algorithm using ANFIS is giving satisfi ed performance than ANN and GABPN with selected statistical data of decomposed levels of faulty current.


4. Novel Method of Network Reconfi guration for the Compensated Network

M. Damodar Reddy and V.C. Veera Reddy

This paper delineates a novel method of network reconfi guration for the compensated network. A two-stage methodology is used to reduce the losses and to improve the voltage profi le of the balanced radial distribution networks. In the fi rst stage, capacitors are placed optimally for the reactive power compensation of the original network. Fuzzy approach is used to fi nd the optimal capacitor locations and Particle Swarm Optimization (PSO) method is used to fi nd the sizes of capacitors. In the second stage, an improved fuzzy multi-objective algorithm is used for the network reconfi guration of the compensated network. The proposed method is tested on 33-bus and 69-bus test systems and the results are presented.

5. Day-ahead electricity price forecasting in Victoria Electricity Market using Support Vector Machine based Model

Sanjeev Kumar Aggarwal, L.M. Saini, and Ashwani Kumar

In this paper, support vector machine (SVM), a new machine learning technique, based model to forecast price profi le in a single settlement real time electricity market has been presented. The proposed model has been trained and tested on data from Victoria Electricity Market (VEM) to forecast the Regional Reference Price (RRP). The selection of input variables has been performed using correlation analysis and in order to take advantage of the homogeneity of the time series, forty-eight separate SVMs have been used to predict next-day price profi le, with each SVM forecasting price for each trading interval. Forecasting performance of the proposed model has been compared with (i) a heuristic technique, (ii) a naive technique, (iii) multiple linear regression (MLR) model, and (iv) neural network (NN) model. Forecasting results show that SVM model possesses better forecasting abilities than the other models and can be used by the participants to respond properly as it predicts price before closing of window for submission of initial bids.

6. The structure and cure mechanism of 2,3-bis(benzimidazolyl) pyridine with an epoxy resin system

P.V. Reddy, Sakuntala Samuelson, M.Nethaji and N.M. Nanje Gowda

2, 3-bis (benzimidazolyl) pyridine was synthesized and characterized by CHN analysis and techniques like infrared spectra, mass spectra and NMR studies. The structure was established using X-ray crystallography technique.

The cure behaviour of 2, 3- bis (benzimidazolyl) pyridine has been investigated with Bisphenol-A based epoxy resin with an anhydride hardener. The study has revealed that this ligand behaves like an accelerator by reducing the cure and gel times of the resin system. Kinetic studies based on DSC showed that the rate of curing increases with enhanced concentration of this accelerator. The electrical properties of the cured epoxy resin were unaffected with lower concentrations of 2,3 bis (benzimidazolyl) pyridine. A mechanism for curing has been proposed based on infrared spectral studies which indicate the involvement of the secondary and tertiary nitrogen of 2,3 bis(benzimidazolyl)pyridine which enhances the cross-linking of the resin system.


7. Optimum Cost of Generation for Maximum Loadability Limit of Power System using Multiagent Based Particle Swarm Optimization (MAPSO)

A.Shunmugalatha and S.Mary Raja Slochanal

To estimate voltage stability, maximum loadability limit (MLL) is one approach. MLL is the margin between the operating point of the system and the maximum loading point. The optimum cost of generation for MLL of power system can be formulated as an optimization problem, which consists of two steps namely computing MLL and the optimum cost of generation for MLL. This paper utilizes the newly developed Evolutionary Multiagent Based Particle Swarm Optimization (MAPSO) in solving this optimization problem. Details of the implementation of the proposed method to modifi ed IEEE-30 bus system, IEEE-57 bus system and IEEE-118 bus system are presented. Simulation results show that the proposed approach converges to better solution much faster, which prove the loadability and applicability of the proposed method.

8. Optimal Coordination of Directional Overcurrent Relays using Charalambous Least pth Algorithm

N. A. Laway

In this paper, a new method for optimum coordination of directional overcurrent relays in interconnected multi-loop power systems is proposed. The method is based on Charalambous Least pth Algorithm. Normally the optimal directional overcurrent relay coordination problem is solved by using Simplex Method of Linear Programming, which is a computationally intensive method. Considerable computational effort can be saved by using the proposed method. The method has been applied to solve the optimal coordination problem of IEEE 14-bus power system and IEEE 57-bus power system. Comparison of the Simplex Method and the Charalambous Method has been carried out for the determination of optimal settings of the relays of the systems under study.

9. A Review on Electrical Treeing in Solid Dielectrics

Michael G. Danikas and George E. Vardakis

Electrical trees constitute a cause of breakdown in solid dielectrics. Electrical trees are related with partial discharges (PD), enclosed defects, which in turn cannot be separated from faulty interfaces. In this review, certain aspects related to electrical treeing, such as space charges, PD and enclosed voids are investigated. Charges, related to the electrical treeing must be classifi ed in two categories. The charges that are redistributed continuously in the interior of the tree channels and charges that are moving and being trapped in the solid dielectric. The fi rst category of charges constitutes the PD charges and the second category charges are referred to as the space charges.


10. Mixed H2/H∞ Control of Continuous-time Singularly Perturbed System - State feedback computations

S A Akbar and A K Singh

This study brings out the scheme for the design of mixed H2/H∞ based feedback controller for a continuous-time singularly perturbed system using state feedback computations. The mixed H2/H∞ control law was derived using auxiliary cost minimization approach and the feedback controller was formulated for a linear time invariant lower and higher order continuous-time singularly perturbed systems by solving iteratively coupled Riccati equations. The H∞-controller based on mixed sensitivity approach and the Linear Quadratic Gaussian (LQG) controller were derived for the same system. The time responses for unit step input and robustness properties such as Gain and Phase margin were studied by formulating mixed H2/H∞, H and LQG systems.

11. Fuzzy Logic Based Fault Type Identifi cation in Radial LT Power Distribution Feeder

Ahalya C and Shivakumara Aradhya R.S.

Fault classifi cation is necessary for rapid restoration of service to LT consumers after occurrence of a fault. This paper presents step by step procedure for identifi cation of ten different types of faults commonly occurring in LT distribution system. Information on the distribution transformer secondary current for different faults at different load buses is used to defi ne the input fuzzy variables. Fuzzy inference engine and centroid de-fuzzifi er are used to relate the input to fuzzy rule base and to obtain crisp output respectively.

12. Performance Analysis of Solar Flat Plate Collectors in Scaling Environment

U C Arunachala, M Siddhartha Bhatt and Dr L. K Sreepathy

Scale formation in risers of solar fl at plate collec tors is evident in places where hard water is being used. This affects both the component functioning as well as system performance. In this paper, the infl uence of scale deposition on instantaneous effi ciency, mass fl ow rate and heat transfer rates are analysed by the Hottel-Whillier-Bliss (H-W-B) equation in both natural and forced circulation systems. It is observed that variation of mass fl ow rate affects collector effi ciency more than variation of heat transfer rates.


ABSTRACT LIST


1. Assessment of Stator Winding Insulation by Spectroscopic and Thermo-Analytical Tech n iq ues

Nageshwar Rao B, Sundara Rajan J and Ramachandra B

Over the past few decades, the progressive deterioration of high voltage machine insulation has been assessed through non-destructive techniques like measurement of Insulation Resistance. Polarization Index. Dissipation Factor, Loss Angle and Capacitance. Partial Discharge (PD) measurements, mainly for trend analysis [1-4]. The stator winding insulation deteriorates under the conditions of thermal, electrical, vibration and thermo-mechanical stresses during service. Aging process is complicated and takes place under stresses simultaneously or sequentially. Thermal aging is a chemical process leading to molecular decomposition and oxidation of organic materials resulting in decrease adhesive strength ot epoxy to mica surface and also to delamination at the interface between mica and epoxy [5,6], Delamination further aggravates under thermo-mechanical force. Small cracks are likely to be generated in epoxy rich areas due to thermal aging which could trigger electrical and chemical changes that insulation undergoes during aging is limited and not fully explored and is of absolute necessity to understand the deterioration mechanisms. This paper reviews the various spectroscopic and thermo-analytical techniques that are used for characterization of materials and presents the laboratory investigations carried out to understand the structural changes that stator winding insulation under goes during aging.

2. Study on Dynamic Characteristics of 3D Reinforced Concrete Frame with Masonry Infi ll

Chethan. K, R. Ramesh Babu, Katta Venkataramanna and Akanshu Sharma

Comprehensive experimental and numerical studies are carried out on the dynamic characteristics of 3 dimensional (D) reinforced Concrete (RC) frame with Masonry Infi ll (MI). MI though considered as non-structural element largely effect strength, stiffness and ductility of the framed structure during the application of lateral loads such as wind and earthquake loads. This paper is a part of collaborative research project between CPRI and BARC focusing on the infl uence of MI on the natural frequencies of 3D RC frame and comparison of the results with the design codes. A 3D RC frame having two bays and three storeys is designed and detailed as per the relevant Indian standard codes. A simple numerical model is been formulated to obtain the natural frequencies in the FE analysis and Tri-axial shake table of 3m x 3m is used for the experimentation. The details of the numerical analysis and experiments carried out in the research work are brought out in this paper.


3. Optimization of Arc Erosion Resistance of Silver Tin Oxide Electrical Contacts Prepared using the Electroless Route

S. S. Godkhindi, G. S. Grewal, P.B. Joshi, M. Ramamoorty, N.J. Buch

The use of cadmium and cadmium oxide containing contact materials has been strongly discouraged in most parts of the world in view of the toxicity of these materials and resultant environmental & health hazards. Tin oxide has emerged as a substitute material in place of cadmium oxide as the major modern silver-metal oxide contact system for industrial application. The traditional methods of synthesis of silver-cadmium oxide composite contacts (namely internal oxidation and powder metallurgy route of co-precipitation) have been found to be unsuitable for production of silver-tin oxide contact material mainly because of incompatibility of existing compounds of tin metal that are water soluble and which can be used for co-precipitation with silver salt such as silver nitrate as well as the very slow rates of internal oxidation of tin in silver-tin oxide system as compared to that of cadmium in silver-cadmium oxide system. For synthesis of silver-tin oxide powders, a novel method based on electroless coating, has been developed. In the present work, an optimization study has been undertaken for improving the arc erosion characteristics of silver tin oxide contacts, prepared using the novel electroless route with additions of a tertiary stabilizing tungsten oxide dopant. The work have been undertaken in a Statistical Factorial Design of Experiment (SDOE) setting using the one way ANOVA technique.

4. Design and Performance Evaluation of FRP cross arm For Transmission Line Towers

Selvaraj.M, Kulkarni.S.M and Ramesh Babu.R

The technology of compaction of power transmission lines is being increasingly adopted by power industry to effectively make use of the Right of Way (ROW). For technical, aesthetic and economical reasons, our future transmission lines will have to be built with new design concepts using new materials. An attempt was made to build the transmission line tower cross arm with pultruded sections of Fibre Glass Reinforced Plastic (FRP) as a substitute for steel. The metallic towers have been deteriorating and corroding as a result of being in hostile environment i.e., wind, rain and salty environment etc. This paper describes the mechanical behavior of FRP tower cross arm assembly simulated using Finite Element Analysis ( FEA) software and compared with experimental results.

5. A methodology for computation of experimental annual station heat rate bench marks

M.Siddhartha Bhatt, S.Seetharamu and N.Rajkumar

This paper presents a methodology for assessment of annual heat rate of a coal fi red thermal power unit based on a snap shot test to which various factors contributing to annual effects are added. This method is successfully used a number of stations and represents the unit heat rate (UHR) and station heat rate (SHR) fairly well. This method is not a substitute for measurement of heat rate by direct measurement of coal fl ow and energy generated and is applicable only where direct measurement of coal fl ow into an individual boiler by gravimetric feeders or belt weighers is not available. This method is superior to other methods in view of its total coverage of all effects and no annual factor which affects heat rate is left out. Hence it is popularly accepted by most thermal stations. This method is superior to backward computation of UHR from SHR by apportioning.


6. Effect of Abrasive types on the Three-body Abrasive Wear Behaviour of Glass-Vinyl ester and Carbon-Vinyl ester Composites

B. Suresha, P. Sampathkumaran, S. Seetharamu and Kishore

Woven fabric reinforced polymer composites are attracting the attention of material scientists in recent years in view of enhancement in physical and mechanical properties as well as ease in processing. Though woven fabric type and lay out of composite is known to control the properties, the information on the tribo-performance of the woven fabric reinforced vinyl ester composites in the literature is scanty. Hence, the present investigation focuses on the vinyl ester based composite reinforced with glass fi bers in one case and carbon fi bers in the other case. They were made by vacuum assisted resin transfer moulding process. Further, the samples were characterized for three-body abrasive wear behaviour using dry sand rubber wheel abrasion tester with two different abrasives (silica sand and quartz). The wear data revealed that the C-V composite showed lower abrasion loss compared to G-V composite. The scanning electron microscopic pictures depicting the worn surface features supported the wear data.

7. Corrective Control Strategies for Mitigation of Line Overloads during Con tangencies

Manoj Kumar Maharana and K. Shanti Swarup

This paper presents a new corrective control strategy to.mUigate the transmission line overloading, with the help of a local optimization concept. A new Direct Acyclic Graph (DAG) technique for selection of participating generators and buses with respect to a contingency is presented. Particle Swarm Optimization (PSO) technique has been employed for generator rescheduling and/or load shedding problem locally, to restore the system from abnormal to normal operating state. The effectiveness of the proposed approach is demonstrated for different contingency cases in IEEE 14 and 30 bus systems. The result shows that the proposed approach is computationally fast, reliable and effi cient, in restoring the system to normal state. After a contingency with minimal control actions.

8. Remuneration towards Frequency Regulation Service Provision in India through A Novel Capacity Linked Mechanism

S. K. Parida, S. N. Singh ,S. C. Srivastava ,and P. Chanda

In India, the frequency regulation service has been provided by the generators ,operating under Free Governor Mode of Operation (FGMO), with certain regulatory basis prescribed by Central Electricity Regulatory Commission (CERC) in Indian Electricity Grid Code (IEGC). No incentive is Being provided towards the capacity reserved for frequency regulation service. In this paper, -a capacity linked mechanism has been proposed in order to encourage the participants to provide regulation service. Index Terms - Unscheduled interchange mechanism, Frequency regulation service, Free governor mode of operation.


9. Optimal Allocation of Distributed Generators in a Competitive Electricity Market

N. Kumar, B.K. Keshavan, R.Nagaraja

This paper presents a sensitivity based technique for assisting network planners to determine the optimal location and capacity of distributed generators (DG) in a capacity and location constrained distribution network with the objective of minimization of losses in a competitive electricity market.

The liberalization of electricity markets has changed the way power generation technologies are valued. The issues that need to be considered in the choice of rating and positioning of DG include both technical and commercial factors. The proposed methodology takes this aspect into consideration and only from among the practicable sites specifi ed by the Distribution system planner both optimal locations and capacity of DGs are determined.

It has been applied to a test system of nine bus radial distribution network considered as capacity and location constrained for implementing DG. The technique is effi cient and very much useful as it can be directly applied to any distribution network having practical constraints for implementing DG.

To show the effectiveness of this technique it was applied to IEEE 6-bus system without any location or capacity constraint and the result was compared with test results of other methods. It is interesting to note that over a wide range of DG penetration the proposed methodology results in largest reduction in loss per unit DG penetration.

10. Ambiguity on the defi nition of Power Quantities in Electrical System

Sujatha Subhash and R K Hegde

This paper aims at presenting a review the defi nitions of power quantities in an electric system with distorted voltages and currents. This subject has been of interest for more than a century and over the years many defi nitions for reactive power and apparent power and compensation techniques have been developed. However none of these defi nitions characterize the distinguishing power quantities for all conditions of electrical circuit. A review of the ambiguities, confusion in the classical defi nition, power theories and diffi culties in instrumentation, billing and compensation is presented in this paper.


ABSTRACT LIST


1. Infl uence of Spin Softening on Natural Frequencies of A Steam Turbine Rotor Assembly with Interference-fi t

B.Gurudatt, S.Seetharamu, P.Sampathkumaran and Vikram Krishna

Vibration is the default state of all mechanical systems that causes them to possess a natural frequency. The signifi cance of natural frequency cannot be emphasized enough, considering the fact that its study is essential in averting resonance which causes violent swaying motions and catastrophic failures in improperly constructed structures. In case of rotating structures, the study of natural frequency is incomplete without the understanding of spin softening. This paper presents an ANSYS based analysis to study natural frequency variation due to spin softening, but in a faster and more accurate way than conventional GUI-based ANSYS analysis. The conventional GUI based ANSYS procedure is a laborious time consuming process, what with the user having to perform multiple iterations of modal analysis involving different rotational velocities to examine the variation of natural frequencies of the system. Through this paper, a novel way has been suggested to bring down the time and effort involved in such a study by using an advanced ANSYS feature called ANSYS Parametric Design Language(APDL). The results obtained have been found to validate spin softening.

2 Power System Stabilization by a Coordinated Application of Power System Stabilizers using Hierarchical Neuro-Fuzzy Logic,

N. Albert Singh, K. A. Muralidharan and K Gomathy

Power system stabilizers (PSS) are used to generate supplementary control signals for the excitation system in order to damp the low frequency power system oscillations. To overcome the drawbacks of conventional PSS (CPSS), numerous techniques have been proposed in the literature. Based on the analysis of existing techniques, this paper presents the stabilization of multi-machine power system based on coordinated Adaptive Hierarchical Neuro-Fuzzy network based power system stabilizer (AHNFPSS) design. The proposed system consists of a Hierarchical neuro fuzzy controller, which is used to generate a supplementary control signal to the excitation system. The proposed method has the features of a simple structure, adaptivity and fast response. The proposed controller is evaluated on a multi-machine power system under different operating conditions and disturbances to demonstrate its effectiveness and robustness. Eigenvalue analysis shows that the undamped modes are sensitive to excitation control while speed governors have little infl uence on damping.


3 Application of Fuzzy logic and particle swarm optimization for reactive power compensation of radial distribution systems,

S. M. Kannan and Others

The main objective of this work is to study optimal location and size of the capacitor to be placed in radial distribution feeders to improve the voltage profi le and to reduce the energy loss. The problem formulation considers three distinct methods related to maximize the savings function and capacitors to be installed, as well as increasing the voltage profi le. This paper uses fuzzy expert system for capacitor location, practical mathematical procedure and particle swarm optimization method for sizing. Initially, the load fl ow solution for the radial feeder os obtained by Newton Raphson algorithm. Voltage, power factor and real power loss index of distribution system nodes are modeled by fuzzy membership function. Then, a fuzzy inference system containing a set of heuristic rules is designed to determine candidate nodes suitable for capacitor placement in the distribution system. Capacitors are placed on the nodes with highest sensitivity index. The sizing is found by using both practical mathematical procedure and particle swarm optimization. Each method differs from others in terms of fuzzy expert system inputs and sizing methods. The intent of this paper is to study and discuss the results of these methods with reference to savings cost. The proposed methods are tested in 11kV, 12 bus IEEE test radial feeder system and results simulated from MATLAB.

4. Impact of DG placement and sizing on distribution system

Tanmoy Malakar and Nidul Sinha

Distributed Generation (DG) technology has emerged as a key important issue in distribution system planning, reliability and optimization for quite sometimes now. Apart from economic power generation and its effi cient transfer, major interests have been observed to plan the distribution system with the presence of small energy sources. This paper addresses a novel technique for optimal placement and sizing of DG into electric power distribution systems. Emphasis has been made to fi nd the impact on voltage profi le and power loss of the distribution network with different DG locations and sizes subject to satisfaction of network security constraints. A power fl ow based simple mathematical formulation has been made. Programs were developed in Matlab for solving the problem. Results reveal that while fi nding the optimal location and sizing of a DG in a distribution system, both power loss and network security aspects of the network must be considered in addition to minimum voltage deviation as they infl uence the optimal results signifi cantly.


5. Optimum Coordination of Overcurrent Relays Using Revised Simplex Method

Prashant P Bedekar and Others

The Over Ccurrent relays (OCRs) are the major protection devices in a distribution system. To reduce the power outages, mal-operation of the backup relays should be avoided, and therefore, OCR time coordination in power distribution network is a major concern of protection engineer. The OCR time coordination in ring fed distribution networks is a highly constrained optimization problem. The purpose is to fi nd an optimum relay setting to minimize the time of operation of relays and at the same time, to avoid the mal-operation of relays. The problem can be stated as a linear programming problem (LPP). This paper presents revised simplex method for optimum time coordination of OCRs in ring fed distribution systems. The LPP of OCR coordination involves large number of variables and constraints. As the revised simplex method works with the reduced table, the amount of computations and the memory requirement is very much reduced. Thus the calculations to be performed reduce to a great extent. Comparison with dual simplex, Big-M simplex and two phase simplex method is also presented.

6. Availability simulation modeling and performance optimization of the screening unit in a paper plant

Rajiv Khanduja, P.C. Tewari, R.S. Chauhan

This paper deals with the availability simulation modeling and performance optimization of the screening unit in a paper plant. The screening unit of a paper industry has four main subsystems, arranged in series and parallel confi gurations. Considering exponential distribution for the probable failures and repairs, the mathematical formulation of the problem is done using probabilistic approach and differential equations are developed on the basis of Markov birth death process. These equations are then solved using normalizing conditions so as to determine the steady state availability of the screening unit. The performance of each subsystem of the screening unit in a paper plant has also been optimized using genetic algorithm. So, the fi ndings of the present paper will be highly useful to the plant management for the timely execution of proper maintenance decisions and hence to enhance the system performance.

7. Dual Mode Linguistic Hedge Fuzzy Logic Contoller for an Isolated Biomass Based Diesel Wind Hybrid Power System with Battery Energy Storage Unit

S. Velusami and M. Md. Thameem Ansari

In this paper, a dual mode linguistic hedge fuzzy logic controller for an isolated biomass based diesel-wind hybrid power system with battery energy storage unit is proposed. In this fuzzy logic controller design, the linguistic hedge operators are used to adjust the shape of the system membership functions dynamically, and can speed up the control result to fi t the system demand. The genetic algorithm-simulated annealing algorithms are adopted to search the optimal linguistic hedge combination in the linguistic hedge module. Dual mode concept is also incorporated in this proposed controller because it can improve the system performance. The system with the proposed controller was simulated and the frequency deviation resulting from a step load disturbance is presented. The simulation results shows that the system performance is improved with the proposed controller. It is also found that the controller is less sensitive to the changes in the system parameters.


8. Sesment of Stator Winding Insulation Part 1 - Review of Condition Monitoring Techniques

Nageshwar Rao B, Mallikarjunappa K, Sundara Rajan J, Ramachandra B and Sudhindra A

This paper reviews the main aging and failure mechanisms of stator windings, as well as the options associated with each mechanism for extending the useful life of the machine. The symptoms for each failure mechanism are discussed. An overview of various electrical diagnostic techniques for condition assessment of stator winding insulation. is summarized.

9. Assessment of Stator Winding Insulation Part 2 - Tests on Inservice Machines

Nageshwar Rao B, Mallikarjunappa K, Keri C.D, Afzal Ahamed, Sudhindra A and Ramachandra B

This paper presents the test results and analysis made on several machines at site. Case studies are employed to illustrate the usefulness of measurements on the stator windings in service.

10. Determining optimum Time Multiplier Setting and Plug Setting for Overcurrent Relays using Continuous Genetic Algorithm

Prashant P. Bedekar,Sudhir R. Bhide and Vijay S. Kale

Overcurrent relays (OCRs) are the major protection devices in a power distribution system. To reduce the power outages, mal-operation of the backup relays should be avoided, and therefore, OCR coordination in power distribution network is of great importance. The time of operation of OCRs can be reduced, and at the same time the coordination can be maintained, by selecting the optimum values of time multiplier setting (TMS) of OCRs. Instead of keeping the value of plug setting (PS) as fi xed (while determining the optimum value of TMS), it is also possible to select the optimum values of both TMS and PS, which can further reduce the time of operation of OCRs. The main contributions of this paper are - 1) systematic method for formulation of problem of determining optimum values of TMS and PS of OCRs in power distribution network as a constrained nonlinear optimization problem, 2) converting the problem into an unconstrained optimization problem, making use of the penalty method, and 3) applying continuous genetic algorithm (CGA) technique to get the optimum solution of this problem.


11. Comparison of tracing based real power transmission loss allocation methods in deregulated power system

S. Arunachalam, D. Ramya and P.K. Nithyha

This paper compares the transmission loss allocation procedures through tracing using proportional sharing rule and provides a detailed comparison of three alternative methods: 1) Graph based tracing 2) Matrix based tracing and 3) complex power fl ow tracing. The methods are based on tracing the real and reactive power fl ow through the network and determining the share of each load on the fl ow and losses through each line. Power fl ows of generators and loads are traced to determine the transmission system usage by each generator and load. Then transmission losses caused by each generator or load are determined. Unbundling, (electric energy can be separated commercially as a product from transmission as a service) an idea, which the current deregulation market hinges on is carried out and considers the coupling between active and reactive power fl ows as well as the cross effects of active and reactive power on active and reactive losses. Tracing algorithms which can be considered direct to a good extent are implemented for these three methods. A case study based on a four buss system is provided and results obtained using MATLAB code is presented


ABSTRACT LIST


1. Investigation of Insulation Performance of High Voltage Rotating Machines using Intelligent Techniques

K.Sathiyasekar, K.Thyagarajah&A.Krishnan

The condition of insulation performance of a high voltage rotating machine has been analyzed using Back Propagation Neural Network (BPN), Fuzzy logic and BPN network with Proportional Integral and Derivative (PID) controller concept along with slope parameter. The economic aspects of its periodic maintenance, the loss in production due to breakdown, the investment cost due to frequent replacement with a new machine is huge. The insulation condition of the machine can be assessed by measuring the various parameters like capacitance, leakage current, dissipation factor, polarization index, surge voltage withstanding strength and partial discharge magnitude. To assess these parameters of the insulations used in high voltage rotating machines, a number of measurements have been made on actual stator coils of machines. For various test voltages, the capacitance, leakage current and dissipation factor are measured and correlated as a function of test voltages. It is observed from the simulation results that BPN with PID techniques gives accurate results, predicting the performance of stator winding insulation.

2. A Low Cost Digitally ControlledBrushless DC Motor Drive Designing

V. M. Takodia, J. J. Patel & M. A. Mulla

This paper presents a low cost, digitally controlled, closed loop BLDC motor drive. Normally encoder feedback is required to get a speed feedback between two hall sensor status changes, for robust controller designing. With a view to reduce the cost, in this design an encoder feedback is avoided and moving average speed estimation with variable Kp-Ki PI controller is realised. The digital controller Cortex M3 ARM microcontroller LM3S2616 is implemented with only hall-sensors feedback and variable Kp-Ki PI controller algorithm. The experimental setup is verifi ed by loading motor from no load to full load as well as with continuous and impact load. Serially, motor parameters like speed, current are gathered on PC and analysed, they confi rmed the simulated results.

3. Development of Small Signal Analysis Package using FACTS Devices for Dynamic Stability Enhancement in Multimachine Power Systems

J.Gokula Krishnan &N.Senthil Kumar

This paper presents a systematic method of developing the mathematical model for small signal stability analysis of power system using different types of FACTS device namely (i) SVC (ii)STATCOM (iii) TCSC (iv) SSSC and (v) UPFC. In this paper, the two axis model of the synchronous machine is used for investigating the small signal dynamic behavior of the multimachine power system. Local stabilizing signals such as real power perturbations, bus voltage deviations are used as control inputs for the damping controllers in FACTS devices. A nonlinear optimization model is developed which tunes the gains, time constants of the FACTS based damping controllers in the stabilizing loop. Case studies are carried out on the standard WSCC 3 Machine 9 – Bus system and the 10 Machine, 39 bus New England system. All computations are carried out using MATLAB v7.6.


4. Digital Real Time Simulator for Testing of Load Shedding Controllers

Meera K.S., J.Sreedevi and R.S. ShivakumaraAradhya

Load shedding is one the main actions that can be used to prevent complete black out in industrial plants during grid disturbances. In case of grid disturbances it is essential to isolate the industrial plant units from the grid as quickly as possible to save the system. In importing mode of operation, it is essential that after grid isolation the generators pick up additional power to meet the plant loads. If adequate generation is not available, loads have to be shed to achieve load-generation balance.

The load shedding schemes are designed based on various factors such as - power import before isolation., excess margin available in inplant generators to pick up further load, response time of governors to changeover from constant power mode to isochronous mode, rate of change of frequency and actual frequency at the time of isolation etc. Thus, such schemes are to be tested under realistic power system conditions including the protections used for islanding the system from Grid. Testing of load shedding schemes requires the use of advanced testing tools to ensure both protection functions and control logic to be tested using dynamic simulations. In this paper, use of Real Time Digital Simulator (RTDS) at Central Power Research Institute, Bangalore for testing of intelligent load shedding controllers is discussed. It is shown that these controllers can be pre-commissioned and tuned, while connected to the simulator in a closed loop.

5. A Novel Implementation Of PspiceModeling ForReliability Analysis Of Distribution Systems

G.N.Sreenivas, P.Srividyadevi, M. DeeptiLavanya andV.Sankar

In this paper, Markov processes for determining the reliability indices of distribution system are discussed. The continuous Markov modeling is applied to a complex radial distribution system and electrical equivalent circuits are developed for the modeling. In general PSPICE is being used for electrical and electronic circuits and various applications of power system like fault analysis, transient analysis etc. In this paper, the SPICE modeling equivalent circuits which are developed are applied in a novel way to Distribution System reliability analysis. These circuits are simulated using PSPICE software to obtain the state probabilities, the basic and performance indices. Thus the basic indices and the performance indices obtained by this method are compared with those obtained by FMEA technique. The application of the concepts presented in this paper are illustrated and analyzed for the IEEE -Roy Billinton Test System (RBTS)


6. Minimizing monsoon load dips in coal fi red thermal power plants

M.Siddhartha Bhatt andN.Rajkumar

Thermal power plants operating on low grade high ash coals experience capacity and performance drops during the rainy season. The parameters like plant load factor (PLF), specifi c oil consumption (SOC), auxiliary power (AP), station load are affected. There are two types of effect: effect of heavy incessant rains for a period of 1-3 days which result in capacity dips and continuous decrease in parameters over the 2-3 months monsoon season caused by decreased handling capacity and fl ow of coal. The effect of monsoons is quantifi ed in terms of deviation in the operating parameters by a study of several stations over a wide geographical range. Typically for a 1 to 3 GW station for short duration (1-3 days) peak load dips of the order of 25-35 %, SOC increase to 25-30 ml/kWh and AP increase by 2-3 % of gross generation are experienced during heavy rainy periods. Instantaneous load dips (2 h duration) can be much higher. For the monsoon season the dips in monthly PLF can be 30-35 %, SOC can be 6-12 ml/kWh, auxiliary power increase is 1.5-3.0 % of gross generation and forced outage % can increase to 4-5 times of the non-monsoon values. The stations need to gear up to the demands of the rainy season through several preventive and control measures. A monsoon management plan needs to be in place for handling O & M in this period on the fuel front as well as on the boiler front. Well planned monsoon management can reduce severity of the power dips to less than 15 % of the peak load.

7. Energy effi ciency improvement in coal fi red thermal power plants through optimization of starts

M.Siddhartha Bhatt, Rajashekar P. MandiandN.Rajkumar

This paper presents a review the impact of transient operations in coal fi red thermal power plants on the unit heat rate (UHR). Once a tripping occurs, fuel oil, auxiliary electric power, steam and coal is consumed to restore the unit back to its original plant level. From boiler light up to almost 20 % load, there is virtually no net generation from the unit. From 20 % load to 80 % load, the energy effi ciency is quite poor and uneconomical because of high auxiliary power and fuel oil support. The annual impact of transient operations is almost 40-50 kcal/kWh in many stations and this can be brought down to nearly 20 kcal/kWh by reducing the number of trippings as well as the resource consumption during these operations. The outage period also need to be brought down from nearly 60-80 hours/outage down to 30-40 hours/outage

8. Least Cost Integration Of Solar Energy Technologies Into Fossil Power Plants

M.Siddhartha Bhatt

This paper presents the optimal integration of solar energy into coal fi red power plants. The solar thermal energy can be integrated through augmentation of heating of make up water in the turbine cycle without any other additional equipment and without interfering with the primary process. Solar photovoltaic (PV) power can be integrated through supplementing the DC emergency loads by charging the battery systems in the power plant. For a 250 MW coal fi red plant, a solar fl at plate collector area of ≈ 8,000 m2 would reduce heat rate by 0.26 %. A PV capacity of 2 MW would be able to provide a continuous capacity of 440 kW to meet the DC loads in normal course and emergency requirements (1 h of autonomy). The capital cost for solar thermal collectors would be around Rs. 7.9 crores and for solar PV it is around Rs. 16 crores. The payback period is around 4.6 years for solar thermal and 10 years for solar PV systems.


9. Effect of Thermal Spraying & Plasma Nitriding Treatments on Fatigue Life of En-24 Shafting Steel

U. N. Puntambekar, G. S. Grewal, P. B. Joshi, P. Sampathkumaran and T. P. Govindan

In the present work, the fatigue strength modifi cation factors for a number of surface engineering treatments on EN-24 shafting alloy steels have been investigated. The surface treatments include, thermal spraying with Alumina & Zirconia & Plasma nitriding with & without white layer. For this purpose, Basquintype relationships for alternating stress versus cycles to failure have been developed. Based on these relationships, the surface treatment modifi cation factors in terms of power law relationships have been evolved.

10. Robust Three Phase Silicon Carbide Heaters Controller Designing

M. D. Raval, V. M. Takodia, J. J. Patel and M. A. Mulla

Silicon Carbide (SiC) is non-metallic high temperature heating element which is widely used in electric furnace and electric heating devices, but SiC heating elements are very sensitive to thermal shock and offer negative temperature co-effi cient of resistance which deteriorate its performances. This paper gives the novel solution of these problems, and discusses a complete design of an electronic heater controller to feed the three-phase SiC elements. The controller enables soft starting, superior dynamic performance, reduce power losses, improves overall effi ciency and high reliability with basic variable AC voltage control capability. A 36 kW three-phase SiC heater controller is designed, developed and tested, which confi rms the theoretical and simulated results.

11. Seismic Qualifi cation Of Transformer Bushing

Srujana Nandam, Indrani Gogoi, R.Panneer Selvam and Ramesh Babu

In the past, Electric Power Substation equipment showed unreliable post-Earthquake performance. The catastrophic failures of circuit breakers, transformer-bushings and disconnect switches at the substations are major causes of outages during past earthquakes. The satisfactory performance of Transformer Bushing system during earthquake is very critical to ensure uninterrupted power supply for effective rescue operations. Many transformers damaged during earthquake were already undergone seismic qualifi cation in the laboratory under real time design Earthquake motion. Experimental test procedures recommended by the relevant Standards are being revised to remove the discrepancies identifi ed. A case study on seismic qualifi cation of transformer bushing by Shake table testing is presented in this paper.


ABSTRACT LIST


1. Experimental Investigations to Aid Interpretation of Frequency Response Analysis Measurements for Diagnosing Transformers

M. Prameela, G. Radhakrishna Murthy and Pradeep M. Nirgude

Frequency Response Analysis (FRA) is an emerging diagnostic tool to assess the mechanical integrity of the transformer. Proper guidelines on using FRA data for declaring the integrity of transformer windings or indicating the extent of displacement/deformations are not yet available. Interpretations of the Sweep Frequency Response Analysis (SFRA) data for diagnosing the condition of the transformer windings are not yet clear. Experimental investigations were carried out on a model transformer to obtain SFRA data for various simulated conditions like axial and radial displacements, winding displacements and deformation, core faults etc for different test confi gurations. The paper presents the results of these investigations and analyse them to form the guidelines in interpreting the SFRA data for various test conditions to detect various type of faults. It is observed from the analysis of results that, SFRA with different test confi gurations need to be applied to detect the type of fault and faulty phase winding. The information presented in the paper, from the simulated faults on transformers with SFRA measurements, will be useful in the interpretation of FRA results to assess and diagnose the condition of transformer windings and core.

2. Simulated Annealing Based Optimal Solution Methodology under Deregulation Power System Environment

Lokanatha Dhall Samanta, Jitendra Kumar Das and Bibhu Prasad Panigrahi

In economic load dispatch solution procedure, the fuel cost characteristics of a thermal generator is usually approximated by (i) a quadratic function (ii) piecewise quadratic function, (iii) a polynomial function with order higher than two. When functions in (ii) and (iii) are adopted the economic load dispatch problem may have several optimum solutions with one being the global optimum solution. To fi nd the global or near global optimum solution, the new algorithm based on Genetic Algorithm (GA) or Simulated Annealing (SA) etc., for solving the economic dispatch problem are needed.

In this paper the generation dispatch methodologies under deregulation power system environment have been developed. The classical economic dispatch algorithm relies on the convexity of cost function. However, in deregulated power market, the market strategies make the sellers’ bidden cost function concave causing classical economic algorithm inapplicable. Here a special type of algorithm is developed based on deregulation strategy and also a heuristic algorithm is proposed which combines with the powerful searching mechanism of simulated annealing with mathematical foundation on global optimization.


3. Challenges and Developments in Numerical DistanceProtection

Venkatesh C. and K. Shanti Swarup

This paper discusses some of the major issues in third generation numerical distance protections which are being faced by utilities and the solutions made available for these issues by relay manufacturers. Each discussion are accompanied with simulation results obtained using matlab and simulink. In addition to this some of the key issues which still need further research are also addressed.

4. Suppression of High Frequency Disturbances in Low Voltage Circuits Caused by Vacuum Circuit Breaker Operation in Medium Voltage Indoor Substation

Chetankumar V. Patel, Varsha A. Shah and Khirad Dhabhar

In a high or medium voltage substation, the operation of circuit breakers can induce high frequency over voltages in low voltage circuits known as an electromagnetic interference (EMI). The radiated and/or conducted EMI can be the cause of damage or malfunction of low voltage electronic equipment. This paper is focused on the effects of electromagnetic interference (EMI) produced due to switching of medium vacuum circuit breakers (MV CB) on the functioning of Numerical relays and measuring devices which are in the vicinity of 6.6kVVacuum circuit breaker and remedy for reduction of effects of EMI. In this paper a unique and cost effective solution has been suggested and implemented to bring down the EMI effects by installation of ferrite core on control cable bunch and effective galvanized iron(GI) sheet shielding between source (MV CB) and victim(numerical relay & meter).

5. Failure of Short Circuit Generators - A Case Study by CPRI Bhopal

Arun Kumar Datta, M. A. Ansari,N. R. Mondal and B. V. Raghavaiah

Switchgear Testing & Development Station prevalently known as STDS was established in 1965 at Bhopal by government of India as one of the unit of Central Power Research Institute. The predominant objective of setting up this institute was to cater the short circuit testing needs of various LT/HT power equipments in switchgear, controlgear and transformer fi eld. Over the years the unit has expanded and received all the national/international accreditations, further became the member of Short Circuit Testing Liaison (STL). Today CPRI’s short circuit laboratories of generator based and direct on line based are one of the leading laboratories in south east Asia.

Year 2006-07 was a test time for CPRI, Bhopal when both the short circuit generators have developed technical snag, resulting in interruption of short circuit testing. It was a challenge for CPRI as well as for the service provider to take repair work as so many technical intricacies were involved including the reverse engineering process. Nation realized the importance of CPRI during the shutdown period. This paper discusses about the occurrence of failure, its detailed diagnosis, root cause analysis and the action taken thereafter. Short circuit generator is different from conventional one in many aspects. Repairing experiences of these generators, along with the re-commissioning process are also shared herewith.


6. Literature Review on Frequency Regulation in Traditional Power Systems Restructured Systems and Smart Grid

Devika Jay and K.S.Swarup

A literature survey on the main control strategies used for load frequency control in electrical power systems is presented. This includes traditional as well as restructured power systems. As load becomes more and more unpredictable and also as supply becomes distributed the frequency control strategies for the emerging Smart grid must include demand-side management also. A survey on demand response and Active load control is also discussed.

7. Establishment of Baseline data in Power Distribution of Electric Utilities in Karnataka under R-APDRP

P.ChandhraSekhar, C.P.Jairam, T.Raghunatha, R.Sudhir Kumar, K.Devendra Rao, VijiBharathi and Kiran. V. Madhugiri

This paper presents the fi eld experience of authors during the establishment of base line data for designated Project Areas under R-APDRP Programme .This paper also brought out sample base line parameters estimation. It also emphasizes problems in the fi eld during collecting data and attempt to overcome the problems. The paper also emphasizes fi ndings on ESCOM by focusing project Area and Aggregate Technical and Commercial loss (AT&C).

8. Battery separator grade PVC resin for possible insulation applications

P.V.Reddy

An emulsion grade resin has been checked for the purpose of battery grade separator properties along with suspension grade PVC resin for insulation purpose. The study suggest that when battery separator resin CP172 SG added to K6701, the elongation property decreases with increase in its content i.e, the material attains rigidity suggesting that CP172SG is not a good absorbent of plasticizer. It has been confi rmed that the particle sizes of these 2 resins are not the same and a just physical mixing need not be a homogeneous mixture and this could affect the properties of the compounded material intended to use for HT cable. The samples CP 172 SG and K6701 both may be used for LT PVC cable sheathing and CP 172 SG cannot be used in XLPE (cross linked polyethylene) LT cables. However, only sample K 6701 can be used for insulation.

9. Technology development of Flame Retardant Low smoke material for wire and cables for sheathing applications

P.V.Reddy

An Attempt was made toDevelop technology for Low Smoke Flame Retardant Cable and Compound with elimination of toxic chemicals in the formulation. The Extrusion trials using twin screw extruder and cable coating with single screw extruder was successful. The results of the evaluation of the cable and compound suggest that the composition seems to be satisfactory. However, large scale production could not be taken due to the actual techno-economic viability of the commercialization. This study paved the way for DSIR sponsored project for commercial exploitation under PATSER scheme.


10. Enhancing Energy Effi ciency of Auxiliary Power in a Coal Fired Thermal Power Plant

Rajashekar P. Mandi and Udaykumar R.Yaragatti

This paper describes the auxiliary power consumption in Indian coal fi red thermal power plants. The factors infl uencing the auxiliary power are discussed in details. Increase in auxiliary power due to lower plant load factor and causes for lower PLF are enumerated. The effect of poor coal quality and their effect on auxiliary power are discussed. The effect of operational optimization, adoption of new energy effi cient technologies, design defi ciencies, etc., are discussed in details along with remedial measures to reduce the auxiliary power. The energy conservation measures reduce the auxiliary power of 210 MW power plant from 11.59 % to 8.50 % with a payback period of 1 to 5 years.

11. Load fl ow study of a radial distribution network

TejasVyas and Ranjit Roy

The paper presents the simple method for fi nding the load fl ow solution of a radial distribution networkusing the Kirchoff’s current and Kirchoff’s voltage law. The method is tested on four test cases: 16-node, 33-node, 69-node and 117-node network. Comparing to the existing methods, the memory space requirement is very small and time required for the CPU execution is also lower. Result shows that the proposed method is very effi cient and competitive with the existing methods.

12. Premature Failure and Remedial measure for Prototype Testing of UHV Transmission Line Towers: an Overview

J. C. Mohanta and D. Revanna

The need for adopting bulk power transmission system with all possible ways to make support structures economical and also to reduce the right of way (ROW) requirements has arisen in view of accelerated growth of electrical network. This bulk power transmission has become compelling due to separation of power sources to the areas requiring the power are at longer ranges, namely inter- state & inter regional. In this direction, 400kV D/C & M/C system with quadruple conductor confi guration, 800kV/1200kV AC system & ± 500 kV/800 kV HVDC systems are now adopted in India. Recently, CPRI has successfully tested the self-supporting type of 765 kV and 800 kV AC and HVDC towers for POWERGRID. The prototype testing and the premature failure of these towers in particular and some of special towers in general are described in this paper.


ABSTRACT LIST


1. Parameters Affecting The Performance Of Transformers Under Short Circuit – A CPRI Experience

YugalAgrawal, M. K. Wadhwani and B. V. Raghavaiah

Transformers are basic electrical machines and they form a very vital link in any electrical power transmission networks. During its service life, a transformer may experience number of short circuits in the system in addition to the abnormal overloading and switching impulses. Such abnormal conditions can cause the movement of the windings and failure of the supporting structures due to electro – mechanical forces and may result in total failure due to inadequacy in design and defective manufacturing process. Further, the rapid growth of fault level in the system network is major a concern for short circuit withstand capability of a transformer in service for a long period of time. With advanced modern technology and available short circuit test facilities, transformer manufacturing industry is now enabling to produce the reliable and safe transformers. Performance evaluation during ability to withstand short circuit test in a fully equipped testing laboratory is still fi nal measure of checking the overall quality of the transformer from the point of design, material used, production process and quality control. Central Power Research Institute (CPRI), is having an experience of more than fi fty years in the fi eld of short-circuit testing. The roles of various factors which affect the performance of transformers under short-circuit conditions are discussed along with the analysis of the failure cases during the short circuit testing.

2. Harmonic Problem due to Saturable Devices in Steel Re-rolling Plant: A case study

Vasudeo B. Virulkar and Mohan V. Aware

This paper investigates the causes of harmonic norms violations in the medium scale (less than 2 MW load) re-rolling industry paying for the penalty. The major drive motor in this industry draws the heavy current with deep in the voltage at the terminal of the motor when steel bars are re-rolled with steps passes. To overcome the problem of voltage deep, the taps of the distribution transformer supplying these loads are selected on higher side. This situation leads to the over excitation of the transformer during the light load condition (between the passes) of the re-rolling operation resulting the operation of transformer in nonlinear zone. During this operation the harmonics due to saturation are generated and injected into the distribution systems and are the cause for damages to the capacitor banks. This problem is analyzed by mathematical modeling of the load condition with the transformer. The site investigation is carried out using power analyzer Megger-PA-9 plus V604 and supported by the simulation in PSCAD/EMTDC. This investigation leads to suggesting the remedial measures which is implemented to accommodate the harmonics inconformity with IEEE-519 standard.


3. Parallel Contingency Analysis for Power Systems Operation and PlanningG. A.Ezhilarasi and K. S.Swarup

This paper proposes a parallel processing approach to contingency analysis (CA) for power system security evaluation. Full AC power fl ow analysis is done for each contingency and violations of bus voltages and line fl ows are evaluated. All possible line outages are considered to avoid overlooking of certain critical cases. Parallel Processing is employed to increase the speed of execution. Parallelism is achieved by sharing each contingency across processors. The proposed methodology is implemented in a Linux Cluster. Data communication is performed through the Message Passing Interface (MPI). The effectiveness of parallelism is demonstrated by performing contingency analysis on standard IEEE Systems. The performance of the algorithm is analyzed in terms of computation speed and effi ciency in comparison with the sequential approach.

4. Operational Optimization of Turbo Generator Units and Auxiliaries in Large Run-off the River Hydro Power Plants

S. Jothibasu

This paper presents the operational optimization to be implemented, based on the energy performance evaluation study carried out in a few large run off the river hydro power plants. The design parameters are compared with operating parameters and the deviations are analyzed. The various operational optimization opportunities available are described in this paper.

5. Application of Directional relay in an Ungrounded Power System to Locate Single line to Ground Fault.

P. Vinod Kumar and Khyati Prajapati

To locate the ground fault in an ungrounded power system is very diffi cult and challenging problem. The single phase to ground fault currents in these systems are much smaller than the required magnitude of ground fault detection devices to operate. It is also important to isolate the single phase to ground fault before restriking of second ground fault on the system to prevent a possible double phase to ground fault. Ungrounded power systems have an advantage of continue the operation with single phase to ground fault but it is also desirable and important to locate and isolate faulted feeder of the system. This paper addresses the potential of identifying faulted feeder by using a high sensitive directional relay which determines the fault current direction in the ungrounded power systems. A MATLAB SIMULINK model is developed for ungrounded 11kV three feeder power system. Single phase to ground fault is created in each feeder and it is detected by directional relay.


6. Application of NSGA-II in solving Multi-objective optimal power fl ow

T.Malakar, S.K.Goswami and A.K.Sinha

This paper is an application of NSGA-II for solving multiobjective optimal power fl ow problems in power systems. Objective function considered in this work are conventional quadratic and emission along with highly non-linear objectives like cost curve with valve point loading and cubic emission function etc. In addition, more than two objectives are optimized simultaneously. The problem is formulated as mixed integer one with both continuous and discrete control variables. The performance of the proposed algorithm has been tested on three different IEEE test systems. Results for the test system-1 have been validated with the reported works. The comparison is done with the classical weighted sum method for IEEE 30 bus system and further experimentation is done on two other test cases such as IEEE-57 bus and IEEE-118 bus systems. The results demonstrate the effectiveness of the proposed approach for fi nding the Power System optimal solutions even when more than two confl icting objectives are considered simultaneously.

7. Synchrophasor assisted Fault Diagnosis using Support Vector MachinePaavani P., Singh S. N. and Srivastava S. C.

This paper presents a Support Vector Machine (SVM) based fault detection, classifi cation and location using synchrophasor measurements obtained from the optimally placed Phasor Measurement Units (PMUs) for ensuring fault observability. An Integer Linear Programming (ILP) based PMU placement method is proposed, considering the minimization of installation cost as objective with line observability as its constraint. The breaker and half bus-bars scheme is considered at one of the substations to show its impact on the Optimal PMUs Placement (OPP). After the OPP, a SVM based post-fault studies are carried out using the synchrophasor measurements, available from the PMUs. Three types of SVM-Classifi ers (SVM-C) are used for the fault detection, faulted line identifi cation and the fault classifi cation. Further, fault location is carried out using Support Vector Regressor (SVR) in which four SVMs are utilized, one for each fault type. The same classifi cation and regression is carried out using Radial Basis Neural Networks (RBFNNs) and the results obtained from SVM are compared. The performance of the proposed method is studied on WSCC 9-bus system with and without consideration of the breaker and half bus-bar scheme and on New England (NE) 39-bus system.

8. Optimal Placement of Power Quality Monitors

D. Saxena, Sayak Bhaumik, S.N. Singhand K. S.Verma

Power quality is becoming a major concern due to increase penetration of power electronics devices and smart grid initiatives. This paper presents an effective methodology to optimally place the Power Quality Monitors (PQMs) to get complete information of the network even under the some outages which makes the system completely observable. Binary Particle Swarm Optimization (BPSO) technique has been used to minimize the numbers of PQM required to make system completely observable and to maximize the measurement redundancy. An index based two-step method has been proposed. Simulation result of the proposed method on IEEE 14 bus system, IEEE 24-bus system IEEE 30-bus system, 13-bus feeder system, 34-bus feeder system, 37-bus feeder system are presented to demonstrate the suitability of the proposed method.


9. Structure Property Correlation and Evaluation of Tensile Properties of Cenosphere Aluminium Composites

Prashanth T., K.Narasimha Murthy and C. K.Umesh

The automobile and aerospace industries relenting passion to enhance the performance of commercial and military applications is constantly driving the development of improved high performance structural materials. Composite materials are one such class of materials that play a signifi cant role in current and future aerospace applications. Composite materials are particularly attractive to both automobile and aerospace applications because of their exceptional strength and stiffness to density ratios and superior mechanical properties. Cenospheres are hollow alumino-silicate microspheres from fl y ash of thermal power stations and are a valuable industrial product due to successful combination of their technical and commercial parameters and can be used as a creation of functional materials. This paper discusses the use of cenospheres as reinforcement in the casting of aluminum metal matrix composite. Based on the metal, reinforcing phases, respective ratios, fl y ash cenospheres – aluminum composite with better features in terms of density, strength and hardness have been developed

10. Foreign & Indian Experience In Policy And Regulatory Issues and Challenges for Private Investment in the Indian Power Sector

I.P.S. Paul and SK.Choudhary

The power sector in India is dominated by the State and Central Government sectors accounting for 44.57% and 30.83% of the generation capacity respectively while the private sector accounts for about 24.58% as on 31.01.2012.The bulk of the transmission and distribution functions are with State utilities. The private sector has a small but growing presence in distribution and is making an entry into transmission. Power Sector which had been funded mainly through budgetary support and external borrowings was opened to private sector in 1991. Electricity is considered key driver for targeted 8 % to 10% economic growth of India. The vast Indian power market, today offers one of the highest growth opportunities for private developers.

11 Coordinated bidding strategy of a supplier in day-ahead and balancing energy market

A.K. Jain, S.C. Srivastava, S.N. Singh and L. Srivastava

This paper presents a methodology to develop an optimal coordinated bidding strategy of a supplier in Day-Ahead Energy Market (DAEM) and Balancing Energy Market (BEM). It is assumed that each supplier bids hourly price-volume bid in DAEM and BEM (for up regulation and down regulation) for 24 hours. In this work, a bi-level optimization problem has been proposed to obtain the optimally coordinated bidding strategy of a supplier, considering rivals’ bidding behavior, inter temporal constraints, and multi period auction. Lower level problem represents the market clearing process of System Operator (SO), in which DAEM and BEM are cleared separately and sequentially for all the 24 hours. Upper level problem represents the supplier’s profi t maximization function, which is non-linear. Therefore, Artifi cial Bee Colony (ABC) algorithm, a modern heuristic approach, has been used to obtain the best solution of the proposed bi-level optimization problem. The effectiveness of proposed method has been tested on modifi ed IEEE 30-bus system. Results obtained using the ABC algorithm has been compared with those obtained using a Genetic Algorithm (GA) based approach. To illustrate the effect of coordinated bidding strategy on supplier’s profi t, results of the coordinated bidding strategy have been compared with those obtained by uncoordinated bidding strategy.


12. Simulation and Experimental Verifi cation of Alternating Current Electric Arc Furnace with Static Var Compensator

Janak J. Patel, H. R.Jariwala and AnkurVashi

Non-linear and erratic loads like an alternating current electric arc furnace with almost instantaneous fl uctuations with its active and reactive power requirements, leads to power quality issues such as poor power factor, harmonic generation etc. We propose to simulate such unique load and prepare its simulation for active and reactive power requirements. Static var compensator is perfect solution for eliminating the above mentioned threats to power quality. SVC behaves like shunt connected variable impedance, which can either generate or absorbs reactive power. [2] Through this review we also present simulation of SVC with AC EAF and prove that all reactive power required by AC EAF during its operation at various power stages is supplied by the SVC only and net reactive power drawn/supplied from system is almost zero in line with actual fi eld practice.


ABSTRACT LIST


1. Optimization of Grading Ring of 624 kV Zinc Oxide Surge Arrester using Finite Element Technique

M.Kanyakumari, R.S.Shivakumara Aradhya, B. Rajaiah, S.Kondala Rao

Zinc oxide (ZnO) surge arresters are being used extensively in high voltage power systems for providing protection to the transmission lines and the associated substation equipment from over voltages caused due to lightning and switching surges. It has been observed in practice that the voltage distribution in a tall multi section arrester under normal operating conditions is quite non-uniform. As a result, the ZnO blocks at the top section share higher voltage and hence higher thermal stresses than the ZnO blocks at the bottom section. This leads to accelerated thermal ageing of the blocks at the top if proper measures are not taken to make the voltage distribution uniform along the entire length of the arrester. Generally provision of grading rings is a common method for achieving uniform voltage distribution through out the length of arrester. In this paper, the results of the optimization of the grading ring dimensions for a 765kV system arrester with a rated voltage of 624 kV using Finite Element based 2-D Elecnet software is presented.

2. Developments and Challenges in Substation Automation

K. Yashwant and K. S. Swarup

This article looks at the development of substation automation systems and associated issues and challenges. The new but already quite popular IEC61850 based substations automation systems are discussed. The issue of interoperability which has been remarkably solved by IEC61850 has also been discussed. Additionally, issues and challenges associated with implementing these substation automation systems have been discussed.

3. On-Line Diagnosis of Power Transformer Insulation System Experience of CPRI, India

H N Nagamani, T Bhavani Shanker

Power transformers play a vital role in handling large amount of power from generating stations (through generating station units-GSU) to transmitting stations (through power transformers) and to end user through distribution transformers. Power Transformers involve large amount of capital investment and the failure of transformers causes severe fi nancial loss to the utility and inconvenience to the end users. Periodic maintenance and condition monitoring are the key factors for successful operation of power transformers. A number of diagnostic tools are in vogue. Most of these tests are conventional off-line techniques and require power shut down and disconnection of transformer from the circuit. Several alternate non-conventional on

-line techniques are being adopted and acoustic emission (AE) technique is one among them. Central Power Research Institute (CPRI), India, is employing AE technique for on-line diagnosis of Power Transformers. Nearly 200 transformers have been tested and investigated covering rating up to 315 MVA, 400 kV.


The paper discusses some of the important aspects of on-line diagnosis of oil fi lled power transformers employing AE technique. A few important case studies which have helped utilities and transformer manufacturers for initiating corrective actions are covered in the paper.

4. Investigation on Polarization – Depolarization Current Measurements in Insulation Systems for High Voltage Motor

Tapan M Rami and Prasanta Kundu

This Paper presents the assessment of insulation systems for high voltage induction motor through measurement of Insulation Resistance, Polarization Index and Polarization-Depolarization Current or Charging and Discharging current. It is considered that the insulation systems are having different types and conditions of insulation aging. It demonstrates that the Insulation Resistance (IR) and Polarization Index (PI) cannot be used individually to judge insulation dryness and the combination of insulation resistance and Polarization and Depolarization Current (PDC) analysis is better technique of insulation quality assessment than the insulation resistance alone. The Polarization and Depolarization Current analysis is non destructive dielectric testing method for determining the conductivity and moisture content of insulation materials in high voltage motors. On the basis of this analysis, it is possible to take further actions like overhauling, drying process, and replacement of the winding of the motor. This paper also presents a description of Polarization and Depolarization Current analysis technique with the practically and theoretical background and some results of Insulation Resistance, PI and Polarization and Depolarization current measurements on High voltage motor.

5. Analysis of Transformer Insulation by Tan Delta testing Method

Dipak Mehtaand Hitesh Jariwala

This paper presents analysis of power transformer insulation by one fundamental insulation Power factor test, also known as Tan Delta. It is a routine test conducted at site to know the healthiness of insulation in transformers. Total 108 no’s transformer tested for research work, out of them 5 no’s case study chosen for analysis purpose. Experimental data shows our experience on the measurement of Tan Delta techniques of earthing systems and dryness of insulation in transformers. Result shows that the Tan Delta testing method is very effi cient method.

6. Optimization of Air Insulation Clearances for EHV/UHV Transmission Lines

Pradeep M. Nirgud B. Gunasekaran R.S. Shivakumara Aradhya

This paper presents the results of the study conducted on 400, 800 & 1200 kV transmission line insulator strings and conductor – tower window geometries with an aim to optimize air insulation clearances. Laboratory investigations were carried out to evolve the switching impulse performance of phase – to – earth and conductor-window confi gurations in addition to the reference rod plane air gap lengths in EHV/UHV range. Tests were conducted on 400, 800 & 1200 kV line confi guration of I, Vee, double Vee etc., by simulating the tower windows. The paper also presents results of the study on optimization of conductor-tower air insulation clearances for adoption in 1200kV AC transmission lines using 8 bersimis conductor bundle carried out for establishment of 1200kV Test Station at BINA, Madhya Pradesh by Power Grid Corporation of India. Results of the tests & the data presented in the paper will be useful for design of phase-to-ground air insulation for adoption in EHV/UHV Transmission lines.


7. Measurement and Control of Electrical Energy For The Effi cient Energy Management

Manish Kumar Ghodki

“Measurement and Control of Electrical Energy for the Effi cient Energy Management” is based on smart energy metering which has its own distribution, controlling and monitoring system for the amount of electrical energy (KWh). It is also equipped with the control of alternative source of electricity (solar energy). This hardware project measures the electrical energy (KWh) as well as controls the amount of electrical energy from supply to load during day and night automatically. The measurement can be performed up to ten lac (10,00,000) units and controlling can be up to two lac (2,00,000) units with a unit range selection of 0 – 20 units and 20 – 2,00,000 units. In the controlling part, when the energy consumption from the mains supply exceeds the preset limit then the mains supply will be automatically tripped and the project provides the alternative power supply in the absence of this mains supply by using the renewable (solar) energy source.

8. Operational Optimisation of Boilers in Coal Fired Base Load Thermal Power Plants

N. RajKumar

This paper describes the performance analysis of steam generators. Various energy conservation measures such as operating excess air level control and insulation condition and its impact on overall heat rate of a thermal power station is discussed. Study results show that the change in operating oxygen level in fl ue gas can give benefi t in unit heat rate to the tune of 10 – 40 kcal/kWh in 210 MW units and 10 – 50 kcal/kWh in 500 MW units. Reduction in the boiler skin temperature from 30 °C to 10 °C above the ambient dry bulb temperature will result in improvement in unit heat rate by 60 kcal/kWh in 210 MW units and 80 kcal/kWh in 500 MW units.

9. Heat Rate Improvement in Utility Power Plants through Steam Turbine Performance Optimisation

N. RajKumar

This paper describes the performance enhancement of steam turbines. Various energy conservation measures such as steam path audit, vacuum improvement in condenser, turbine retrofi ts, feed heater performance improvement, etc are discussed. Study results show that the improvement in operating turbine effi ciency will lead to a quantum improvement in unit heat rate from 25 to 225 kcal/kWh.

10. Enhancement of Energy Effi ciency of hydro Turbine Generators by energy conservation techniques

Rajashekar P. Mandi and Udaykumar R Yaragatti

This paper describes the results of enhancing energy effi ciency of hydro turbines by implementing the energy conservation measures for hydro turbine generators. The procedure for evaluating the on-line performance of generators is discussed. The energy saving in generators by maintaining optimum generator terminal voltage, by reducing the stator winding temperature by improving the performance of coolers and reducing the excitation loss by appropriate tuning of excitation system are enumerated in details with case studies. The implementation of energy conservation measures have a techno-economic feasibility with a payback period of 1 to 5 years.


11. Erosion resistance of Chromium – Manganese iron alloy cast in metal and sand moulds: PLS & DBAR studies

P. Sampathkumaran, C. Ranganathaiah, P. K. Pujari, S. Seetharamu and Kishor

The wear resistant high chromium (Cr: 16 – 19 %) iron alloyed with 5 % and 10% manganese (Mn) were produced in metal and sand moulds by induction melting technique. The erosion resistance, hardness and microstructure were evaluated both in the as-cast and heat treated conditions. The advanced non-destructive test (NDT) methods namely Positron Lifetime Spectroscopy (PLS) and Doppler Broadening annihilation radiation (DBAR) studies using variable energy positron beam were made use of to study the infl uence of metallurgical parameters on the defect sensitivity in the bulk and surface of the alloy. The data reveals that as the mould type is changed from metal to sand, the hardness decreases irrespective of the sample condition (i.e., as-cast or heat treated), whereas the erosion volume loss shows an increasing trend. The light and scanning electron microscopy give good support to these data fi ndings. It is observed that faster the cooling rate (metal mould), fi ner is the carbide size precipitation on the surface of the sample. The PLS data reveals that the defect size and its concentration are higher for sand mould alloy compared to metal mould. The reasons for lower erosion loss and fewer defects of smaller sizes in metal mould are attributed to faster heat transfer in the metal mould compared to the sand mould. Further, heat treatment of the samples yielded spherodization of carbides in the matrix and some of the defects seem to have been annealed out leaving only fewer defects of smaller size in the alloy. The S-parameter profi les of 10 % Mn both in AC and HT samples are almost identical indicating near absence of any modifi cation of defect structure near the surface following heat treatment in 10 % Mn sample while 5 % Mn samples exhibit less defect concentration both at the surface as well as in bulk which agrees with the PLS results. Hence, the 5 % Mn bearing metal mould sample in the heat treated condition is preferred choice as it shows higher hardness, lower erosion loss as well as least defect concentration with smaller defect sizes. Based on this investigation, a good correlation among erosion loss, DBA and PLS data has emerged.

12. Stack Optimization of Thermo acoustic Refrigerator

B.G. Prashantha, M.S. Govinde Gowda, S. Seetharamu andG.S.V.L. Narasimham

The performance of the thermoacoustic refrigerator depends upon a very large number of parameters and hence the components are optimized using linear thermoacoustic theory to restrict the number of variables by dimensionless normalization technique. Since the stack is considered as the heart of the thermoacoustic refrigerator, the stack design parameters are the most signifi cant parameters for the optimal overall performance. The stack optimization result shows that a decrease in stack length and center position from the loud speaker increases stack performance. Determination of optimum stack length and center position helps in designing the refrigerator and to provide adequate space for instrumentation in practical work. The cross-sectional area of the stack and hence the stack diameter is calculated for the required cooling load capacity which is considered as the basic parameter on which the design of other components depends. The effect of mean temperature of the gas has not received attention in the literature and hence the performance of the stack at higher mean temperature of the gas is theoretically evaluated.The improvement in the stack coeffi cient of performance COPs is reported compared to published experimental optimization studies at the design conditions considered in this paper and the results are in good agreement with past established work.

A Golden Jubilee Edition, Vol. 8, No. 2, 2012

ABSTRACT LIST

THE JOURNAL OF CPRI - A Golden Jubilee Edition, Vol. 8, No. 2, 2012

1. Central Power Research Institute: Over Five Golden Decades of Dedicated Service to the Nation

Central Power Research Institute (CPRI), an autonomous Society under the Ministry of Power, Government of India was set up in 1960. The Institute has rendered over fi ve decades of dedicated service to the Power Sector. The paper details the journey of CPRI from its inception, establishment of state-of-art specialized R&D and Testing Facilities viz. Short Circuit testing, High Voltage testing, Power System studies, Power Cables and accessories, Energy meter, Design of Transmission Line Towers and testing, Conductor Vibration Studies, Transformer Oil, Power Capacitors, Solar and LED Lighting Systems which has resulted in recognizing CPRI as one of the largest Research and Test House in the world catering to the entire gamut of services covering Generation, Transmission and Distribution under one roof. The decades witnessed the expansion of CPRI activities and besides Bangalore and Bhopal, CPRI Units were established at Hyderabad, Nagpur, Noida, Kolkata and Guwahati. Pioneering Research work aiding the Utilities and Industry and expansion of Field testing, Consultancy/System studies, Monitoring and Inspection achieved a healthy growth. The Institute during these years was able to enhance its brand equity and cater to the requirements of the Overseas Customers.

2. R&D Efforts of CPRI: Sustenance of Technologies and Focus on Challenges for the Future

With its state-of-the-art infrastructure and expertise, CPRI has made signifi cant contributions to the power sector in the country for improved planning, operation and control of power systems. Besides in-house R&D, CPRI also undertakes sponsored research projects from manufacturers and other agencies in different areas of specialization in Power Engineering. CPRI has completed 50 years of dedicated service to the Indian power sector. With a humble beginning in the year 1960, CPRI has grown from strength to strength and today it has a major role to play in all the ambitious plans, projects, schemes of Ministry of Power, Government of India. CPRI under the guidance, support and encouragement of Ministry of Power, will forge ahead to serve the Indian Power Sector in a big way. CPRI also looks forward to work in close cooperation with the Indian Power Industry and the Academia for achieving the economic growth and prosperity of the country.


3. Centre for Collaborative and Advanced ResearchThis center established in CPRI, Bangalore is aimed to function as a center of excellence in collaborative and advanced research in the power sector. The infrastructure for electric power generation, transmission and distribution is aging and requires signifi cant research and development and the introduction of new technologies. Talents and strengths of CPRI based scientist and engineers will be used to close the gap between fundamental research and pre-commercial development programs.

Each technical group will focus on a key area in the power sector and provide a network of coordinated research activity through collaboration with national and international laboratories and industries. The main aim is to encourage an integrated approach to innovation through cross–disciplinary projects. Using the combined technological capabilities of CPRI and other agencies, it is aimed to generate cutting edge research that can be quickly translated into practical application.

This center of excellence would also provide the education and training necessary to create and maintain an educated work force for fi elds currently experiencing personnel shortages. In response to the shortage of engineers and scientists in areas of power generation, transmission, distribution and utilization a comprehensive educational and research program is required. CCAR infrastructure must be more effectively utilized to provide education and training and support continuing education programs.

The Center for Collaborative and Advanced Research (CCAR) would have a research consortium that includes universities and other research organizations. The goals of CCAR are to create an environment in which universities, industry and R&D institutions work together to promote and enable collaboration, to provide a forum for exchange of information and ideas, and to create solution to complex and diverse problem facing the electrical power industry. CCAR is especially interested in technical problems associated with the new institutional arrangements that are occurring under a restructured regulated power industry.

The aim of CCAR is to promote research cooperation with industries in the fi elds of power system, power electronics etc. The institution – industry consortium can further integrate the research and education resources within CPRI and serves as a platform for research collaboration. CCAR will also cooperate with other power engineering related institutes to advocate these fi elds of study and boost participation of research scholars.

To exchange views on need based research programmes between the R&D institution and industries, CCAR shall organize the annual review meeting and short courses on various topics. Engineering from industrial partners can participate in these events to catch up on the latest development of power technologies, and also to visit the laboratory facilities of the CPRI to see the progress of the research work.

4. A Successful Journey of Fifty Years: Switchgear Testing and Development Station, Bhopal

As a member of CPRI family, the Switchgear Testing and Development Station, Bhopal has become an independent knowledge leader of high quality services, research and development. From a small entity at the beginning it has developed to cater the requirement of Testing and Certifi cation needs of Electrical Equipments manufacturers and utilities in India as well as foreign countries within fi ve decades. This article briefs about features of different STDS laboratories and their growth from the grass root level. Some of the nostalgic memories are also shared upon.


5. Growth and Contribution of The High Voltage DivisionThe High Voltage Laboratory at Bangalore was initiated around 1964 in the campus of Indian Institute of Science, also called as Tata Institute. the period between 1978 and 1983 in the history of the High Voltage Laboratory of CPRI could be termed as very productive in building up the expertise in R&D, testing and consultancy that paved way for formulating a road map for ensuring a bright future for the high voltage engineering in CPRI. The activities of the division can we attributed to EHV Test Laboratory (Main Laboratory), Mobile Field Testing Laboratory, Pollution laboratory, Impulse Current Laboratory, Development of measuring equipment like Electro-static fi eld measurement instruments, High Voltage Test and Measurement Instruments and other developments include Grading Ring for EHV/UHV Insulators and Surge Arresters, and Minimum clearance requirement for transmission towers of 765 kV System.

6. Ultra High Voltage Research Laboratory, HyderabadEstablishing an experimental UHV transmission line facility in India was undertaken, with funding from Government of India, to carry out studies facilitating possible introduction of UHV lines in the voltage range of 800–1200 kV AC of and to establish high-voltage test facility for the development of equipment by Indian manufacturers and also for the purpose of quality assurance testing of these apparatus. Research facilities at UHVRL have been set up mainly to undertake major electrotechnical and biological research and development studies and also to undertake testing activities for equipment ranging up to 1200 kV. The Impulse laboratory facilities available at UHV Research laboratory, CPRI, Hyderabad are of world class and at par with international laboratories like-CESI, EdF, KEEMA laboratories etc. Power equipment manufacturers, EHV/UHV transmission grid operators and utilities can avail the services to evaluate their equipment and sponsor the research work of their interest.

7. High Power LaboratoryTo meet the growing needs of short circuit testing of switchgear and power transformers, the high power laboratory was established in CPRI, Bangalore, in 1991. The laboratory was planned with total installed capacity of 7500 MVA, which is to be achieved in three stages. In the fi rst stage, 2500 MVA direct test facility with parallel current injection synthetic test circuit was installed. The technical consultancy for the laboratory was provided by EDF High Power Laboratory, Les Renardiers, France. The vital equipments of the laboratory, viz, short circuit generator, short circuit testing transformers and the master circuit breakers and make switches, are specially designed with essential technical characteristics required for short circuit testing of switchgear, power transformer and other electrical power equipments. The laboratory is having the most modern measuring, control and protection equipment. The short circuit and switching tests conducted in the laboratory are strictly in accordance with IS, IEC, ANSI standards. The short circuit generator has been converted into motorless system with state-of-art technology electronic controllers, which ensure trouble-free testing service to customers from our country and abroad. The two decades of service rendered by CPRI High Power Laboratory has resulted in quality-rich, reliable switchgear and power equipment for the utilities and end users. The laboratory is providing continual service to nation building activities in the fi eld of power sector.


8. Short Circuit LaboratoryThe original set-up consisted of 12 kV 50 MVA Short-Circuit (SC) Generator driven by 3.3 kV induction motor and a DC shunt generator coupled to the Generator shaft. Set-up also consisted of auxiliary equipment like Air-blast Master Circuit-breaker for breaking the short-circuit current and a high speed Make Switch for initiating the short-circuit, protection system for drive motor and Generator, Control Desk, Measuring/recording system, etc. As there was demand for the DC Short-Circuit test from the various manufacturers 600 V, 30 kA DC short-circuit test facility was created under 8th Plan capital project. This is the only unique DC short-circuit test facility available in India even today for testing LV DC equipment like MCBs, MCCBs, switches, contractors, fuses etc. An impulse test facility for up to 30 kVp was also created for carrying impulse tests on LV equipment. The laboratory contributed a lot in the indigenous development of HRC fuses and Moulded Case Circuit Breakers with electronics trip circuits by English Electric Company, indigenization of Circuit Breakers used in completely self-protected (CSP) transformers, medium-voltage vacuum contractors, etc.

9. Insulation Division The Insulation Division was founded to promote R&D activities related to power industries. The Division gradually created facilities to undertake R&D, Evaluation studies on insulation materials. Many research Projects were conducted encompassing vast area of electrical insulating materials. A few notable among them are evaluation of electrical varnishes, motorett Coils, impregnated electrical paper. Institute has also executed several accelerated aging projects, which include acceleration studies on different classes of insulating materials such as (i) Class B, (ii) Class H and (iii) Class F. Presently the Division is providing fi eld services for RLA of power station and substation equipment. Apart from other reachers activities.

10. Evolution of Diagnostic LaboratoryThe Diagnostic, Cables and capacitors Division (DCC Division) formerly known as Cables and Capacitors Laboratory (CC Laboratory) during 1970’s was mainly involved in testing of low voltage (LV) and medium voltage (MV) cables, LV capacitors and heat run testing of bus bars/ducts, panels as per National/International Standards. During 1980’s with the induction of young engineers and scientists the laboratory initiated R&D projects related to the functional evaluation of insulation systems of power cables, power capacitors, rotating machines, traction motors and the like. The decade 1990 was remarkable from the point of view of diagnostic on-site testing and Remaining Life Assessment (RLA) studies on power plant electrical equipment. As there was no established diagnostic testing method for condition assessment of power cables, DCC Division introduced for the fi rst time in the country Very Low Frequency (VLF) tan delta testing for diagnostic testing of XLPE power cables. The DCC Division conducted the VLF tan delta testing on 33kV class XLPE cables at Rourkela Steel Plant in 2007 and detected the manufacturing defects in the cables.

11. Evolution of Insulation Materials LaboratoryThe details about formation of Insulating Materials laboratory, its comprehensive growth over fi ve decades, in research, testing and consultancy areas is presented in this article. This write up covers the historical perspective, research contributions including product development, various national and internal committees represented and allied.


12. Power Cables LaboratoryThis paper presents bird’s eye view of contribution made by Power Cables Laboratory of CPRI during the Golden Jubilee period 1960–2010 towards research, testing and certifi cation. The laboratory started way back in 1960 at the Indian Institute of Science campus, Bangalore with bare minimum test facilities. The laboratory assisted many of the Indian cable industries by providing consultancy and testing services for improvement and produce better quality cables. Over the years the laboratory has been augmented with the state of art test facilities for research and qualifi cation tests on power cables and materials. At present, CPRI has state art of facilities for testing of cables and accessories of voltage rating up to 220 kV rating. CPRI is setting up facilities for Pre-qualifi cation testing of 400 kV EHV XLPE Cables as per IEC-62067. With this facility, CPRI test facilities will get enhanced to type testing and pre-qualifi cation tests of cables up to 400 kV voltage rating. The research activities undertaken in this laboratory during this period is summarized.

13. Power Capacitors for AC Power System ApplicationCentral Power Research Institute, Bangalore, is playing an important role in the development of the capacitor industry by providing required facilities for research, testing and evaluation of power capacitors. With the help of these facilities, all types of power capacitors, like all fi lm capacitors, composite dielectric capacitors, metallized fi lm capacitors, etc. are being tested and evaluated. In addition to facilities for routine and type testing of power capacitors according to the IS Standard, sophisticated and expensive equipment for conducting more stringent tests like Endurance test on full-size capacitor units up to unit rating of 1 MVAr and partial discharge test based on advance acoustic emission technique are available in the Capacitors Laboratory of CPRI, Bangalore. Facilities for testing high voltage series capacitors have been developed including discharge current test, disconnecting test on internal fuses and cold duty test. In the fi eld of LV capacitors, special test facilities for charge-discharge and destruction test have been augmented to meet the requirements according to the revised IS:13341-1992. Test facilities are also available according to the UL safety requirements. Capacitor manufacturers in the country and from abroad are availing the facilities of CPRI. Experience of CPRI during testing of different types of LV and HV capacitors of unit rating ranging from 1 kVAr to 1118 kVAr for the last 10 years for will be covered in the paper. Some of the important issues like (a) factors infl uencing the capacitor losses, (b) infl uence of dissipation factor on the performance of LV capacitors during 1500 hours aging test, (c) performance of full - size HV capacitors under cyclic over voltage applications at different lower temperature limits, (d) operation of internal fuse, (e) testing of special capacitors for space applications, (f) factors infl uencing discharge current characteristics for series capacitors, and (g) acoustic emission technique as one of the NDT methods for performance evaluation, etc. will be discussed in the paper.

14. Power Systems DivisionPower system division carries out Power System Planning, operational studies, relay coordination studies, power system grounding and earth mat design. Power systems division with its state of the art facilities and latest software tools offers a wide range of power system simulation services, including real time performance analysis of various types of controllers such as FACTS, HVDC, SVC and protection relays. It has been conducting studies for the past two decades for its own needs and at the request of utilities, manufacturers and end users of electric power. To carry out such studies the division posses Real Time Digital Simulator, E-Megasim electric power system simulator and different off line power system analysis software packages like SIMPOW, NEPLAN, EMTDC, etc.


15. Distribution Systems DivisionThe Distribution System Division (DSD) was established in CPRI in September 2008 and has a team of professional engineers with vast experience in offering consultancy in Power Distribution System for Utilities and Industries. With the state-of-art facilities and software tools, the Division has been rendering consultancy services in fi nding solutions to various problems faced by the Electricity utilities and industries in the area of power distribution. The consultancy services are extended to the Electricity Regulatory Commission in estimation of losses in Distribution networks in various states.

16. Utility Automation Research CentreUARC division has a very long and interesting history in CPRI. In the very beginning after CPRI was established, CPRI started using computers for solving electrical power systems and structural engineering problems. The journey of computers in CPRI started during early 1960’s with the development of computer programmes on the fi rst and oldest computer in Bangalore namely Elliot 803 at HAL. During the second decade i.e 1970–1980 the mainframe computer IBM 360/44 and then DEC (Digital Equipment Corporation) 1090 which replaced IBM 360/44 in IISc were used for power system, High voltage and transmission tower testing related problems. During fourth decade i.e. 1990–2000 the IT infrastructure witnessed a phenomenal growth. Tens and hundreds of Personal computers were procured and upgraded from time to time. Local Area Network was created during 1997–1998. During the fi fth decade i.e. 2000–2010 CSET division has come into full pledged operation. The development of CPRI Automation System (CAST) started during early part of 2000s aiming at the automation of workfl ow, testing and other support activities. The IT in the form of, Intelligent Meters (IM) became a reality during early part of 2010. Followed with this initiative “Conformance Test Laboratory” was established during 2004.2005. “Gyanshakthi” a knowledge management and digital library intranet portal was launched during 2005 which facilitated sharing and seeking knowledge among CPRI fraternity.

17. Material Technology Division - Overview and Way ForwardMaterials Technology Division came into existence during the year 1985–1986 and is signifi cantly contributing to R&D, Testing and Evaluation, Consultancy Services and IPR. The division is equipped with advanced and sophisticated materials evaluation facilities aimed at providing technical services in the areas of materials for the power sector.

Considering the signifi cance of the growth of scientifi c and technological advancements in the power sector for generation, transmission and distribution including renewable in the country, the division has focused its efforts in pursuance of the mission of the organization and the engineering services provided in the area of condition monitoring, renovation, modernization and life extension of power plant and equipment through diagnostic and life extension studies for achieving economy and reliability in the power sector.

The text of the paper describes the overall growth of the division as well as its contributions to other divisions / units and the Way Forward.


18. Dielectric Materials DivisionDielectric Materials division has established an excellent reputation and is known all over the country for its expertise in testing of insulating oils and also for diagnostic testing of materials for their condition assessment. Presently, the division has a full-fl edged laboratory infrastructure for testing new insulating fl uids to test according to the IEC 60296. Testing of in service oils according to the IS 1866-2000 for condition assessment as well as diagnostic information. Division has also basic infrastructure for testing Lubricating oils particularly fully equipped to test the turbine oils. Division also has basic characterization facilities to evaluate polymeric materials.

19. Polymer LaboratoryPolymer Laboratory of CPRI was established during 1976 to cater to the needs of power industry in terms of Research and Development, Testing and Consultancy works. The laboratory has taken up good number of projects and completed successfully. Scale up studies have been done for development work done on Flame Retardant Low smoke PVC based cable compound and Synthesis of Novolak Resin for electrical applications. Project works have been completed which have resulted in award of doctorate and Masters degrees for several workers from different Universities. The laboratory has published several papers in International Journals besides papers presented in National seminars & conferences in addition to several product developments resulted in the form of patents. Technology development studies have been carried out for the patented product developed by involving private industry and project was sponsored by Department of Scientifi c and Industrial Research (DSIR) under PATSER scheme. The laboratory was also successful in conducting few consultancy studies to satisfy the requirements of electrical utilities.

20. Regional Testing Laboratory, NoidaThe Regional Testing Laboratory (RTL) at Muradnagar has been functional since 1992 to cater to the growing needs of northern power utilities and industry. Due to the proximity and inconvenience to the clients the unit has been shifted to Noida and the laboratories have become functional since June 2009. The important facilities cover Cables Testing upto 33 kV, High Voltage Laboratory for testing Insulators and Transformers and Transformer Oil Testing Laboratory. The new facilities for testing of Energy Meter and Diagnostic Testing facilities have been created at the new centre. A large number of clientele covering utilities and industry has been established over the years. The unit is having ambitious plans of augmenting facilities for Diagnostic Testing and also set up new facility to cover more products.

21. Regional Testing Laboratory, KolkataRegional Testing Laboratory Kolkata was set up in September 2006 with a view to cater to the testing, certifi cation and evaluation needs of electrical power equipment manufacturing industries, utilities and consumer in the eastern region. It also acts as a liaison unit of CPRI with various clients in the region and coordinates their test requirements which are beyond the scope of RTL, Kolkata but within capabilities of Bangalore and other units of CPRI. The major power utilities catered to by RTL in the region are PGCIL, DVC, NTPC, NHPC and state electricity boards of Bihar, Jharkhand, Orissa, Sikkim and West Bengal. Thus, the objective of CPRI Laboratory in Kolkata is to cater to the need of electric power utilities in the eastern region. A large number of power utilities are already in operation in the region. There are 49 power generating stations, 31 and 72 sub-stations of 400 kV and 220 kV capacities respectively in the region. CPRI is having ambitious plan to fulfi ll the need of test facilities in the region. The laboratory is going to take up expansion in its facilities to accommodate complete oil testing including testing of new oils, condition monitoring of substation equipment and studies on distribution transformers.


22. Regional Testing Laboratory, GuwahatiThe idea of setting up a Regional Testing laboratory in North East was conceived in 2005–2006. The Government of Assam and especially the Assam State Electricity Board (ASEB) took a keen interest in the project and with their sincere cooperation and necessary funding by the Ministry of Power, Govt. of India, the idea of a Regional Testing laboratory materialized in Guwahati. On 20th July 2007, the offi cial journey of the Regional Testing Laboratory, Guwahati was set off. Apart from regular testing activities, the RTLG is also acting as a coordinating center between the potential clients of this region and the other divisions of CPRI.

23. Thermal Research Center - A Hub for Knowledge Source in Thermal Generation Sector

Thermal Research Center, a unit of Central Power Research Institute, is to carry out Research and provide appropriate solution in the Thermal Generation.

This Center is recognized as “A Well Known Remnant Life Assessment Organization” for carrying out RLA Study of Boilers in India, awarded by Central Boiler Board, New Delhi, for conducting RLA Study of steam and process boilers under Indian Boiler Regulation 1950. Thermal Research Center is providing services in the areas of Non-destructive and Destructive testing, Failure analysis of power plant components, Condition assessment of power plant components, Condition assessment of civil structures with the latest technology and advanced equipment available. This Center has served almost all the power plants and other Industries of India in the last 18 years.

24. Energy Effi ciency and Renewable Energy DivisionRenewable energy especially solar, wind and biomass was recognized as the future energy source for India during the late 1960s and 1970s. CPRI installed water pumping windmills as early as 1976. The CPRI began the work in energy effi ciency in 1979 recognizing its importance to the power sector. The work began with product development for energy effi ciency and renewable energy and branched out into consultancy services for energy audits and power plant engineering. The developments is traced from 1976 till present and the salient achievements are the development of PRIYAGNI (PRI-Power Research Institute) wood burning stove, one of the fi rst designs of compact fl uorescent lantern, biomass gasifi er and Stirling Engine. On the consultancy side the salient achievement is the energy audit of thermal and hydro power stations across the country. The Division has contributed in its capacity to the making of the Energy Conservation Act 2001, Electricity Act 2003, National Electricity Policy 2005 and all other major energy related legislation.


25. Electrical Appliances Technology DivisionDomestic Electric Appliances Testing facility was a part of Insulation Laboratory during 1976. Further battery testing facility and Relay testing facility were added. An off shoot of this activity was formation of a new Division called Distribution Division with main aim of taking R&D activities in the Distribution System, Optimization studies and also caters to the testing and certifi cation of Domestic electrical appliances, batteries and Relays. During the period from 1985 to 1995, this division has added new facilities for testing of fans and also environmental testing of panels, In mid nineties, the Distribution Division leaded to the formation of Electrical Appliances Technology Division with main intension of Environmental testing of panels, testing and certifi cation of Domestic Electrical Appliances, Fans, Relays and Batteries. With the enactment of Electricity Conservation Act 2001 and BEE’s prime program of Standards and Labeling of Electrical Appliances, The Division has shifted its activity towards check testing of appliances viz. Refrigerator, Air conditioner. TFL and Ceiling Fan under Standards and Labeling Program for star rating. Many State of the art test facilities have been established in the Division for this purpose and the Division is having ambitious plans for setting up of new facilities for testing of Motors and also augment the existing facility to cover more products viz. T5 lamps, Refrigerators up to 2.5 m high, Batteries of various types and also to increase the bench capacity for testing.

26. Instrumentation DivisionInstrumentation Division (ID) was established during the year 1976 with an aim of identifying the problems encountered by Power Utilities and Energy Meter manufacturers in the area of Generation, Transmission and Distribution and also to provide consultancy services. Many problems were identifi ed by the division, developed and provide solutions. Some of the them are Cable fault Locator, Earth fault Indicator for fl oating DC Control cables, Time Synchronizing Unit, Single and Three Phase Static Energy Meters, Electronic Trivector meters, Powered Support Characteristics Recorder for Underground Coal mines. Instrumentation Division has obtained Patent for Cable fault locator and Time Synchronizing Unit while Earth fault Indicator for fl oating DC Control cables, Single and Three Phase Static Energy Meters, Electronic Trivector meter Technology was transferred to private entrepreneurs for commercialization. During the year 1995, it was decided to it was decided to render services in new area i.e. Testing and certifi cation. In 1995, Energy Meter Testing Laboratory was established at a cost of ` 85 lakhs. The project was funded by Ministry of Power. Energy Meter testing Laboratory was established with an aim to cater the requirements Power Utilities as well as Energy Meter manufacturers. Subsequently calibration and Relay testing Laboratories were added. During the year 1998, EMI/EMC Laboratory was added to Energy Meter Testing Laboratory. With this facility, ID established full state of the art Technology for energy meter testing under one roof.

Instrumentation Division also established Mobile Energy Meter Testing Laboratory during the year 2007 with an objective to verify the performance of energy meter (In-service) at Consumer premises on behalf Power Utilities or public Grievances Cell as the case may be. At present the mobile energy meter testing lab is stationed at New Delhi.


27. Vibration and Seismic Qualifi cation of Products and EquipmentVibration analysis and testing helps to accelerate progress in many industries, including aerospace, automobile, Electrical equipment manufacturing, power generation, defence, consumer electronics and telecommunication. Vibration tests are carried out to identify and eliminate unwanted vibration to improve product quality and durability. Many standards have been evolved over the years to prescribe suitable test procedures for qualifying the fi nished products and equipment. Earthquake Engineering and Vibration Research centre (EVRC) is equipped with state-of-the-Art facilities to carry out vibration and seismic tests according to the National and International Standards.

28. Mechanical Engineering Division - Design CellThe Design cell at Mechanical Engineering Division was created in 1980’s with objective to support the Tower Testing Station activities and take up the consultancy works on design of towers for new transmission lines, analysis and checking of towers designed earlier for further optimization of weight, checking the adequacy of existing towers for up-rating a line, redesign of existing towers with least modifi cations for upgrading etc.

29. Mechanical Engineering Division - Tower Testing StationThe Mechanical Engineering Division established in 1976 and prior to this, the Model Tower Testing Laboratory was also established and was operational. All though some of the tower manufacturers have tower testing facilities and being captive in nature and not available to others in the fi eld and experiencing delay in commissioning of transmission projects, the Government of India decided to setup a tower testing station under CPRI.

Based on the requirements and foreseeing the future power demand and forecast for new power projects in the country, Prototype Tower Testing Station (PTTS) was established and commissioned during 1976 (Inaugurated by Ministry of Power).

The station was opened to commercial tests as third party certifi cation as well as for R&D oriented tests with the concept of development of new designs in transmission towers and a full fl edged model tower testing laboratory was strengthened/established during 1982.

The requirement for testing other transmission components like conductors, insulators, etc. Vibration Laboratory was established during 1978. Further, due to installation of new transmission lines of higher rating of 400 kV and above, for studying the Vibration characteristics of hardware/accessories Wake Simulation Laboratory established during 1985. Further, during the year 1990 Foundation Testing Centre was established.

Over the years the division has been augmented to facilitate higher category/rating of transmission towers and its components in line with growth of power industry. CPRI is an R&D Institute and for catering to the needs of utilities to facilitate the design, development and testing of the various components of overhead transmission line system under one roof, the division established a design and consultancy wing. The standardization of transmission towers, design and analysis of transmission towers were facilitated since 1980.


30. Mechanical Engineering Division - Vibration LaboratoryThe Vibration Laboratory and Wake Simulation Laboratory are very oldest and unique in its nature, were established in Mechanical Engineering Division in the eighties. These two laboratories were come into existence under the leadership of Shri T.V. Gopalan who headed the Mechanical Engineering Division nearly more than a decade. It would not have been possible to have such a wonderful laboratory as stood up-front today than as it was seen before was probably with able guidance and support from Shri C.S. Sreenivasan, who served the Institute as Director from 1980–1983.

The Vibration lab was fi rst established in the year 1980, while the Wake Simulation Laboratory was subsequently came into existence after few years. Special thanks and credit goes to Shri T.V. Gopalan, as Head of Mechanical Engineering Division for having constructed the WSL at very low expenditure by using tested tower parts and employing the in house welders. As on today and as things stand on, we are quite confi dent of offering our high ended services in terms of product development, Research and testing not only limited to power sector but also to others.

31. A Bird’s Eye View of CPRI Library and Information CentreThe CPRI Library and Information Centre, Bangalore was established with the inception of the Institute in the year 1960 with 400 books donated by CWPC. Over the years the library has grown up in many folds and CPRI has established Digital Library, Knowledge and Information Centre.


ABSTRACT LIST


1. Experimental Investigation on Model Transformer Windings to Analyze Axial and Radial Displacements

M. Prameela,G. Radha Krishna Murthy &Pradeep M. Nirgude

Sweep Frequency Response Analysis (SFRA) method is an effi cient method for predicting the geometric changes and research on the optimum and unambiguous application is still in progress. In order to correlate integrity of transformer windings with changes in the frequency responses, lot of measurements have to be performed and analyzed. The present work discusses special experimental investigations carried out on model transformer winding to study the various aspects of axial and radial winding displacements using SFRA test. The experimental results for axial and radial winding displacements are presented and analyzed. The analysis will help in understanding the health of an actual transformer and diagnosing it for any impending fault with respect to winding movements.

2. A Comparison of PI Tuning by Direct Search and Genetic Algorithm for Optimal Control of AGC in Continuous-Discrete Mode

Debashisha Jena, Mokenapalli Vijay

This paper deals with Automatic generation control (AGC) of interconnected hydrothermal system in continuous-discrete mode using proportional-integral (PI) controller with different tuning approaches. Here the PI controller is initially tuned using local optimization technique such as Fminsearch (Existing MATLAB function) and optimal control strategies were taken as integral square error (ISE), integral time-absolute error (IATE) and integral time square error (ISTE). Then the same PI controller is tuned by using evolutionary algorithm i.e. Genetic Algorithm (GA).For the given system appropriate generation rate constraint (GRC) has been considered both for the thermal and hydro plants. System performances are examined considering 1% Step Load Perturbation (SLP) in both thermal and hydro area with 1 second sampling period. Finally the performance of both the local and global optimization algorithms is compared in terms of the time domain specifi cations both for frequency deviation in each area, and tie line power.

3. DG placement in radial distribution network with reconfi guration

Tejas Vyas & Ranjit Roy

This paper presents a simple method for fi nding the optimal DG size and optimal DG location in distribution network. By using this method optimal DG capacity and location is determined considering without network reconfi guration and with network reconfi guration. The method is tested with three test cases: 33-node, 69-node and 117-node IEEE standard network. Result shows that the proposed method is very effi cient and competitive with the existing methods available in the literature.


4. Design of artifi cial intelligence based load frequency controller for a two area power system with super conducting magnetic energy storage device

R. Jayashree

Superconducting Magnetic Energy Storage (SMES) unit with a self-commutated converter is capable of controlling both active and reactive power simultaneously and quickly, increasing attention has been focused recently on power system stabilization by SMES control. In this study, a self tuning control scheme for SMES is proposed and applied to Automatic Generation Control (AGC) in power system. The system is assumed to be consisting of two areas. The proposed self-tuning control scheme is used to implement the Automatic Generation Control for Load Frequency Control (LFC) application adding to conventional control confi guration. The effects of the self tuning confi guration with Artifi cial Neural Network (ANN) in AGC on SMES control for the improvement of Load Frequency Control is compared with that of Conventional Integral controller, PI controller, Fuzzy Proportional Integral Controller (FPIC). The effectiveness of the SMES control technique is investigated when Area Control Error (ACE) is used as the control input to SMES. The computer simulation of the two-area interconnected power system shows that the self tuning ANN control scheme of AGC is very effective in damping out of the oscillations caused by load disturbances in one or both of the areas and it is also seen that the ANN controlled SMES performs primary frequency control more effectively compared to Integral controller, PI and FPIC controlled SMES in AGC control.

5. Fuel & Cost Optimization of Grid Connected MTG-PV Based Hybrid System

Grishma J. Patel & ShabbirS. Bohra

A MTG-PV hybrid system is a reliable DG based system because PV is unpredictable non-traditional energy source whereas, Micro-turbine is a controllable traditional energy source, which will cancel out each other’s drawbacks. In this paper, a microturbine generation system (MTG) is considered as the backup generation, to meet the energy requirements when solar energy is not suffi cient. Main objective of this paper is optimization of Fuel & Cost of grid connected MTG-PV hybrid system. Analysis of power management & fuel optimization is carried out using the MATLAB/SIMULINK platform. HOMER (Hybrid Optimization Models for Energy Resources) power optimization software by NREL (National Renewable Energy Laboratory) is used to optimize the cost of the hybrid system.

6. Comprehensive Study on Central Control Management of a Power Distribution System

Subhashree Patra & K.S Swarup

The purpose of this study is developing a familiarity with the central control and management functions, the nerve of any power system. The paper considers a distribution system and emphasizes on a distribution management system (DMS). DMS uses state estimation to maintain the healthy working condition of the system. It plays a very important role in the control of the distribution system as the level of control possible is restricted owing to the specifi c structure of distribution networks and penetration of real-time monitoring and control facilities. So far the level of SCADA implementation in distribution networks has controlled around 10% of switching devices and has been limited to circuit breakers at the larger primary substations. The four main functions of the DMS have been discussed focusing mainly on Outage Management.


7. Voltage Sag Mitigation in Three Phase Induction Motor using DSTATCOM and DVR

B.V.Ramprasad & Khyati Mistry

Voltage sag in distribution system is one of the most frequently occurring power quality problem. There are many solutions to mitigate voltage sag. This paper describes one such technique to mitigate voltage sag occurring during starting of three phase induction motor by using power electronic devices called Dynamic Voltage Restorer (DVR) and Distribution Static Compensator (DSTATCOM). This paper is organized with brief introduction of voltage sag and its characteristics, structure and control principles of DSTATCOM & DVR. The performance of both DSTATCOM and DVR to mitigate voltage sag caused by starting of three phase induction motor is observed and compared. The simulation models of both the devices are analyzed and results are shown.

8. Diagnostic Testing of Hydro & Turbo Generators andLarge AC Motors in service

K. Mallikarjunappa, Chandrashekar D. Keri, V. Vaidyanathan Thirumurthy, T.R. Afzal Ahmed

Majority of the generating sets operating in our country are turbo generators contributing nearly 70% of the total electrical power generated. Many of these generators are about 30-40 years old and have already come to the end of their notional design life. In recent times, with the ever growing demand for power, high cost of new equipment and paucity of funds there is an increasing trend to upgrade and extend the life of older generating sets. It has been recognized that with the advent of new technologies there is a scope for upgrading of generating capacity of the generators. In the light of this, knowledge of integrity of these machines and their remaining service life would be of great interest. In this, endeavor, there is a strong incentive for condition assessment of various components of these machines. Over the years many diagnostic tests have been suggested for condition monitoring of different components of the machines. The data obtained from these tests provide much needed information regarding present state and condition of the components.

9. Seismic performance of 245 kV current transformer

Srujana N, Ramesh Babu & Katta Venkataramana

Substation equipment whose natural frequencies lie in the normal frequency range of earthquake ground motion are particularly vulnerable to damage by seismic events. Electric power systems, are expected to be functional during and after major earthquakes and it is vital to sustain economic activities and assist recovery, restoration, and reconstruction of the damaged structures and equipment during earthquakes. Current transformer (CT), usually having a narrow long porcelain insulator is the most vulnerable part subjected to earthquake. This paper evaluates amplifi cation factor in terms of acceleration from the ground to top of the support structure where the current transformer is mounted. Sine sweep tests are conducted on current transformer with support structure to evaluate its dynamic characteristics using shake table tests. The ground motion amplifi cation obtained from fi nite element analysis and shake table tests is compared.


10. Impact of ultra violet radiation on an artifi cially polluted silicone rubber during inclined plane tracking test

S.Ganga, N.Vasudev, V.Asai Thambi, R.S.Shivakumara Aradhya & A.Sudhindra

This paper presents experimental results obtained on the tracking and erosion resistance of Silicone rubber (SIR) with and without pollutants. The IEC 60587 Inclined Plane Tracking and Erosion Test method combined with UV radiations of different intensities were employed to assess two different formulations with same base polymeric material (SIR). The hydrophobicity recovery property of silicone rubber formulations before and after inclined plane tracking test was studied besides the effect of corona. Some of the physical, thermal and electrical properties were compared before and after inclined plane tracking test. It is inferred from the analysis carried out on the experimental results that, the intensity of UV radiation plays a major role in deteriorating the surface characteristics of the material. It is also found that the introduction of UV in the test method has helped, in distinctly evaluating polymeric materials. The effect of two different pollutants was not the same on formulations considered for the study which implies that, the additives play a dominant role in the overall performance of the material than the base polymer. The study also revealed that a formulation with better performance under a certain pollutant need not behave the same way under a different pollutant. As presently, CIGRE Working Group (WG D1.14) is active in standardization of material aspects besides developing suitable methodology for the testing of polymeric materials for outdoor insulation application, the inferences appear to be an useful input to both CIGRE working group and International Electro technical Committee (IEC TC 15 PT 2).

11. Critical speed analysis of a single stage impulse type high-speed steam turbine rotor disc

B. Gurudatt, S.Seetharamu, P.Sampathkumaran, Vikram Krishna

Resonance is a common thread that runs through almost every branch of engineering.Yet, this phenomenon often goes unnoticed, silently resulting in inconveniences, such as causing a bridge to collapse or a helicopter to fl y apart, to name a few. It is therefore of utmost importance to avert resonance, for which determining the frequency of the system becomes indispensible. In complex rotating structures, as one considered in this paper, theoretical determination of frequency is as diffi cult and laborious as a task can be. Finite element analysis has proven to be an effective tool to handle such a task. Resonant vibrations incited by the running speed harmonic excitations, steam impinging frequency, engine order excitations are fundamental causes for failure of turbine components. The mainstream discipline that is encompassed by this paper is the modal analysis. Modal analysis is performed to estimate the critical speeds and study the mode shapes of the bladed rotor disc under prestressed condition.


12. Energy enhancement of plate shear line in Essar steel limited with advanced ac drive system

B.K.Thummar, V.A.Shah, A.K. Panchal

This paper represents the comprehensive study, analysis and result achieved by data evaluation of AC drive system over DC drive system in Essar steel Limited in India. With innovations in advanced direct torque control and vector control technologies, performance of AC drives are similar to DC drives in entire speed range. Usage of these advance speed control techniques in AC drives gives excellent result to achieve desired torque- speed characteristics, dynamic response and over load capabilities similar to DC drives. In February 2010, replacement of DC drive system by AC drive system was carried out in hot rolled plate shearing line (PSL), which is cut to length application line in steel plant. By various technical and fi nancial comparisons, it is found to use of AC drives more economical in comparison with DC drives. AC drives ensures, improvements on energy effi ciency, reliability and enhancement of production with reduction in cost, maintenance and equipment down time. After replacement from DC drives to AC drives following performance observed in PSL:

Energy saving of 1.88 kWh/t.•

Production rate increased from 55 t/h to 95 t/h.•

Line speed increased from 19.5 to 23 m/min. •

Line stoppage time reduced from 2000 to 300 min./year.•

Vol. 8, No. 4, December 2012

ABSTRACT LIST

THE JOURNAL OF CPRI - Vol. 8, No. 4, December 2012

1. Recent Trends in Evaluation of DLMS Meters as per Indian Companion Specifi cation

Pradish M, Suresh V and Arunachalam V

The requirement of an Open Protocol for energy metering was a long awaited and most required standard for bringing in homogeneity among various makes of meters deployed in the fi eld by the Power utilities. The openness of the standard will make the Automatic Meter Reading (AMR) and interoperability into reality. This open protocol based on IEC-62056 (DLMS/COSEM) helps to overcome most of the challenges for data acquisition for the utilities. The Indian Companion Specifi cation (ICS) was evolved by BIS as an Indian Standard IS-15959 which inherits the IEC-62056 series of standards. This paper brings out the advantages of ICS and tests being performed for compliance.

2. IEC61850 Standard and It’s Impact on Protection and Control Schemes within Power Sub-Station

Viral Joshi and Varsha A Shah

IEC61850 developed by International Electro-technical commission (IEC) is an approved International standard for communication within the substation. It has introduced many new features which can be used to build various applications for Protection of various equipments within the substation. This paper there for focuses on various possible protections schemes based on GOOSE messaging facility available in IEC61850 standard, its advantage/disadvantage over Hardwire conventional protection scheme and cost effectiveness of implementing this new scheme for an existing energy company.

3. Hybrid State Estimator with SCADA and Phasor Measurements

Jamuna K and Swarup K S

This paper investigates the problem of combining both the Supervisory Control And Data Acquisition (SCADA) measurements and phasor measurements for state estimation. The SCADA measurements are slow dynamic in nature than phasor measurements. The latency between those measurements is compensated using Auto Regressive and Neural Networks. Weighted Least Square estimator technique is used for estimating states of the power system. A Traditional State Estimator (TSE) solution is obtained using SCADA measurements which already exist in energy management system. The proposed work is performed on the TSE estimated states for future state prediction. Future TSE state estimates are predicted at the instant of Phasor Measurement Unit (PMU) measurements received at the energy management systems. Auto Regressive, Feed Forward Neural Network and Nonlinear Auto Regression exogenous models are used for state prediction and the effectiveness of these models are evaluated. Then, the state vectors of Hybrid State Estimation (HSE) are calculated using predicted state vector and selected PMU measurements. The Neural Network based SE provides best state estimates over AR based SE. The working of the proposed process is validated through the simulations carried out on standard IEEE 14 bus, 30 bus, 57 bus and 118 bus systems.


4. Recent advances in HV and EHV Power Cable technology CPRI’s Experience in Qualifi cation Tests on Power Cables

Nageshwar Rao B, Meena K P, Thirumurthy and Raja G K

Over the years both due to demand and technological advancements there has been a continuous transition from smaller operating voltages of 6.6. kV to higher voltages of 500 kV. The conventional technology like taping or fi eld moulding are in vogue and new technology like pre-moulded slip on cable accessories are gaining importance for jointing of polymeric high voltage cables up to voltages of 500 kV. The fl ammability characteristics of polymeric materials used in cable insulation and jacketing have been of great importance over the years. Evaluation techniques have become more stringent and both short term and long term tests are conducted in order to ensure the quality of materials used, the manufacturing processes, workmanship and reliability. In this paper the recent advances in HV and EHV power technology is summarized and the experiences in testing and evaluation of 220 kV cables is presented and discussed.

5. A Multilevel Inverter Based Series Active Power Line Conditioner for Voltage Sag and Swell Mitigation

Raihan Kagzi and Mulla M A

Series Active Power Line Conditioner (SAPLC) is a custom power device which protects the sensitive loads against the voltage sags and swells. This paper presents three level diode clamped inverter with DC storage capacitors along with three single phase transformers as a SAPLC. Modifi ed scalar control strategy with fast response time is used to improve the performance of SAPLC. The simulation of the proposed model is carried out to verify the performance of SAPLC in conditions of balanced sag, balanced swell and unbalanced sag. Results are analyzed to check the effectiveness of the proposed model with selected control strategy.

6. Implementation of Shunt Active Power Filter Based on a Simple Novel Control Algorithm

Vijay K Patel and Mulla M A

Shunt active power fi lter are commonly used as a harmonic and reactive power compensator. In this paper, a simple control method is described to control shunt active power fi lter. It operates on constant switching frequency, hence switching losses and stresses on the devices are lower. It can compensate the reactive power required by the load without sensing and computing the associated reactive power component, thus control circuit is made simple. It can also compensate harmonic components of the non-linear loads. The experimental results are agreed with the analytical and simulated results.

7. Wind-Fuel Cell Base Hybrid Energy System for On-Grid Electrifi cation of Villages

Prashantkumar Pandya and Ranjit Roy

This paper introduces method for on-grid electrifi cation of villages. A potential function for each component like wind turbine, fuel cell, voltage regulator unit, control box, DC coupling device and DC blocking device is used in this work. Secondary voltage control is achieved through voltage regulator unit. The studies are simulated in time-domain continuous mode using MATLAB/Simulink. Wind-fuel cell based hybrid energy system is tested with various wind speed. It is observed that the proposed system is working satisfactorily.


8. Fuzzy Controller Based STATCOM for Grid Connected Wind Generator

Muni Reddy G, Gowri Manohar T and Jyothsna Priya V

When integrated to the power system, large wind farms pose stability and control issues. A thorough study is needed to identify the potential problems and to develop measures to mitigate them. Although integration of high levels of wind power into an existing transmission system does not require a major redesign, it necessitates additional control and compensating equipment to enable recovery from severe system disturbances. In this paper, the STATCOM control scheme for the grid connected wind energy generation system for power quality improvement is simulated using MATLAB/SIMULINK in power systems block set. Fuzzy based controller is designed to improve the source current in STATCOM. A marked reduction in the Total Harmonic Distortion is observed in source current of Wind Power Generation System (WPGS) with the incorporation of Fuzzy controller.

9. A Novel Approach to Harness Maximum Power from Solar PV Panel

Mrityunjaya Kappali and Uday Kumar R Y

Among alternate sources of electricity, Solar Photo Voltaic (PV) energy is gaining prominence due to its plentiful availability. It is not being opted for in large numbers as grid parity of cost has not been achieved. By harnessing more power per unit installed capacity of the solar panel, the cost can be reduced. One of the methods of realizing this is by Maximum Power Point Tracking (MPPT) wherein a power electronic converter is used to match the load with the PV panel. Widely employed approach for MPPT is to monitor the power generated by the PV panel and keep on adjusting the duty cycle of converter so that this power is always maximum.

Present paper proposes a novel method to realize MPPT for standalone solar PV system with resistive (R) load. It is shown that the output power becomes the maximum when the load voltage becomes the maximum. Conversely, varying the duty cycle of the converter such that load voltage is always maximum leads to harnessing maximum power output. This approach can be referred to as Maximum Load Voltage Point Tracking (MLVPT). Only one parameter i.e. load voltage needs to be monitored. It is simpler than monitoring PV panel power as in that case it’s necessary to measure both panel voltage and current and then fi nd their product.

The proposal of MLVPT for realizing MPPT is substantiated by theoretical explanation. Simulation as well as experimentation are also carried out. The results are found to be in close conformity with the theoretical fi ndings.


10. Performance Evaluation and Financial Analysis of Solar Industrial Oven Using Pair of Scheffl er Refl ectors

Ajay Chandak and Sunil Somani

To deal with climate change and fossil fuel depletion problems, direct utilization of solar energy is the most promising option. Innovating new technologies and exploring possibilities to fi nd new applications for existing technologies is the key to resolve this problem. Scheffl er solar concentrators based steam generation systems are successfully deployed for community cooking applications in India. There is need to look beyond cooking and develop different commercial and industrial applications using Scheffl er solar concentrator as a primary heat source. An Industrial Oven is developed by authors for catering mid temperature applications in Industries, which utilizes Scheffl er solar concentrator of 16 m2 as a prime source and two such concentrators focus inside a single oven. This innovation delivers 9 kW, which is good enough heat for many industrial applications in 100°C–200°C range, replacing electricity or fossil fuels like LPG or diesel. The trials show excellent technical and fi nancial viability of the new design. Depending on fuel to be replaced, payback period varies from 2–6 years. Paper discusses development process of the new product and fi nancial analysis for the same.

11. Optimization of Annual Energy Generation in run of the River of Hydro Power Plants

Siddhartha Bhatt M and Jothibasu S

Annual variation in water infl ow down to 50 % of its maximum value is quite common in run of the river hydro plants (with storage of 1–3 hours of power generation capacity) with multiple stations located on the same river in intervals of 30–50 km. The low capacity factors (< 40 %) call for effi cient water management for modulation of unit and station loads to co-ordinate operations and maximize energy generation. The effi ciency characteristics (which represent the utilization effi ciency of water resources)of the hydro units are not fl at but decrease with decrease in load. The net operating effi ciencies of individual hydro power plant units decrease sharply at lower loading levels below 80 % of the rated capacity due to swirling and vorticity components on one hand and erosion-cavitation on the other hand. The parameter (Pmin/Pmax) amongindividual units infl uences the net overall effi ciency to the tune of 2–10 % points in multi-turbine, multi-station environments of a river. By optimal selection of the loads to maximize this parameter, the energy generation can be maximized. The ultimate solution to optimal water utilization is to achieve a fl at effi ciency curve over the load range through 3-d designs of turbine runner. Silt control also plays a role in the energy effi ciency but is controllable and secondary.


12. Thermal Management of LEDs for Lighting Solution

Ingole Sunil B and Sundaram K K

Lighting is rapidly transitioning from conventional lamp resource such as high-pressure sodium, metal halide, mercury vapor, and fl uorescent to high brightness light-emitting diodes. Standard incandescent lamp have luminous effi cacy as 16 lm/W, whereas LEDs are expected to be 90 to 140 lm/W, with the life of LEDs to be 50,000 hrs. As effi ciency and drive current increase, the total lumens per emitter increases, reducing the initial cost of light and by providing energy savings. In LED lighting about 30% energy is distorted in light, whereas 70% is parting as heat. The junction to ambient resistance can be varied by using active cooling systems. Also the term used is Enhancement Factor (EF) of the active cooling devices. Enormous scope is observed in deviation of material and their combinations for effective thermal investigation. Variety of active and passive heat removal techniques are reported and hybrid systems are evolving. A range of aspects of thermal management, its need and scope is presented in view of developing LED lighting solutions for general household and corporation applications, which will be of great help for saving nation’s wealth, by saving power utilization in lighting the country.

13. Study on Estimation of Lifetime of Transformer Oil in Service

Maiti P K

Lifetime of a transformer depends on the age of its electrical components, liquid and solid insulation. So study on ageing of oil is equally important as that of the solid insulation. The oil under service is subjected to thermal and electrical stress. Presence of oxygen and moisture and contaminants act as catalyst to accelerate the ageing process. Oil is regularly monitored to assess the extent of ageing. It is also desirable to establish the remaining life of the oil at various point of time during its service period. In order to do that it is required know the rate of degradation of oil under operating conditions. It is well known that the operating conditions vary from one transformer to other and which is further infl uenced by the environmental factors. Due to these facts, the ageing of oil is considered to be a complex process. This suggests that the study to be conducted on large number of transformers in order to get a representative ageing characteristics. In the present study, a large number of oil samples drawn from power transformers of various age groups were analyzed. It is observed that deterioration of Interfacial tension and acidity is almost linear with service period and can fi nd application in assessing lifetime of the oil.


14. Basics of Dissolved Gas analysis and Case studies for Power Transformers

Dipak Mehta and Hitesh Jariwala

Electrical insulating oils of petroleum origin are extensively used in transformers. The physical, electrical and chemical properties of such oils are subject to change due to environment and electrical stresses. For use in any electrical apparatus the oil has to comply with certain requirements and determination of these properties before fi lling the apparatus is of utmost importance. It is also equally important to monitor the condition of oil in service. Condition Monitoring of Insulating oil of power transformer is performed by oil contamination and dissolved gas analysis. In Oil contamination test comprise of breakdown voltage, water content, neutralization value, sediment & sludge, resistivity, dielectric dissipation factor, interfacial tension and fl ash point. DGA analysis is obtained by IEC ratio method, Rogers ratio method, Key gas method and Dual triangle method to distinguish the possible fault types by analyzing the amount of gases dissolved in the insulating oil. Total 108 no’s transformer tested for oil contamination test and dissolved gas analysis. Out of them 3 no’s case study chosen for analyzing Insulating oil condition. Also other 2 no’s case study is chosen from Different industries for analysis purpose.

15. Studies on the Effect of Additive Package in Enhancing the Lubricant Properties of Gear Oil

Muralidhara P L, Kavyashree M J, Gowrishankar B S, Jagannadha Rao Y and Jayarama Naidu C

The aim of this research study is to study the effect of gear oil additive package with base oil. The formulation of this type of lubricant is based on gear oil additive package with stable base oil. The study evaluates the laboratory testing results for oils obtained from mixture of base oil and gear oil additive package and the optimization of additive package to the base oil for better performance when compared to commercially available gear oil in market. The values of the properties of the additive blended with base oil depend on the characteristic of mineral base oil and the concentration of the additive package.

16. Physico-Chemical Studies on the Effect of Package Additives in Automotive Engine Oils

Muralidhara P L, Guruprasad M, Nirguna Babu P, Jagannadha Rao Y

and Jayarama Naidu C

Lubricating oils are extremely essential for the operation of modern automotive machinery. They are formulated by blending special purpose chemicals into Base oil of crude origin to achieve desired properties required by application at hand. In the present work, commercial package additive (multi-chemical compound) has been used to formulate the Engine Oil. The blending proportion of package Additives are varied from 0–15 volume % and its tribological properties are measured using standard test methods. The Physico-chemical studies on the effect of addition of package additives to formulate automotive engine oil are studied and reported.


17. Transformer Fault Analysis Using Finite Element Method and Frequency Response Analysis

Pritesh Bhoniya and Prasanta Kundu

With the appearance of deregulation, distribution transformer predictive maintenance is becoming more important for utilities to prevent forced outages with the consequential costs. To detect and diagnose a transformer internal fault requires a transformer model to simulate these faults This Paper presents here an approach has been shown for transformer fault analysis. A transformer model was designed for a 10 MVA, 132/66 kV three phase system. Data for all the parameters essential for designing a transformer were calculated, after studying machine designing. The next task was to calculate the inductance and capacitance (lumped values) which is later on used to make the ladder network which represents the transformer as inductance capacitance model. After dividing the total inductance and capacitance into segments the ladder network is ready to be used for short circuit fault analysis. Artifi cial faults were created by shorting a few segments at a time and the output voltage corresponding to input voltage under different faulty conditions were noted down. These values were used to create a frequency response curve which was compared with the response under normal condition and further analysis was done.

18. Investigations to Identify SFRA Measurement Sensitivity for Detecting Faults in Transformers

Pritesh Bhoniya and Prasanta Kundu

A common failure mode for power transformers is consequent to mechanical deformation of the core or windings. Core damage is more likely as a result of transportation, while winding damage is more likely to be caused by short circuit type forces. Sweep Frequency Response Analysis (SFRA) is an effective low-voltage, off-line diagnostic tool used for fi nding out any possible winding displacement or mechanical deterioration inside the Transformer, due to large electromechanical forces occurring from the fault currents or due to Transformer transportation and relocation. This paper describe through case studies that SFRA test is more sensitive to detect faults compare to conventional testing method.

19. Thermography – A present Trend of Condition Monitoring for Electrical Equipments in Petroleum Industries – Research Data

Prashantkumar Koradia and Prashantkumar Pandya

Thermography (thermal imaging) has evolved into one of the most valuable diagnostic tools for predictive maintenance. By detecting abnormalities often invisible to the naked eye, thermography allows corrective action to be taken before costly system failures occur. The paper introduces the method of condition monitoring of running equipment using thermography followed in refi nery for last 4 years and the results obtained considering the same. The failure and breakdown were predicted before the occurrence of the same. The occurrences has been lower down from 3.21%–0.25% to total installed equipment per year while the failure rate reduced from 0.29%–0.02% per year.


20. Six Sigma Analysis of Electrical Motors in Refi neries Combining Criticality Index and Condition Monitoring of Motors using Vibration Analysis

Prashantkumar Koradia and Bhusavalwala M N

To achieve the goals of management for six sigma level breakdowns, zero accidents, and zero effect on quality of product along with least maintenance cost, the concept of RCM had helped engineers a lot. The primary need for RCM is deciding criticality index number and CM and PM frequency are decided thereafter based on criticality score ensuring the coverage of all the critical equipment. As CM and PM of all equipment is time consuming, more concentration should be given to equipment with higher criticality. Electric motors have seen to be widespread adoption in every application and their condition monitoring has received considerable attention in recent years. Motor’s abnormal vibration signals include its fault information and these vibration signal analysis is used to monitor motors to predict and prevent major problems. Condition monitoring using vibration analysis has achieved meaningful results in successfully diagnosing motors problems. This paper introduces a way for risk assessment approach to decide criticality index of equipment in petroleum refi nery and combining the same with CM technique like vibration analysis for motors in petroleum refi nery for achieving zero breakdowns in motors with the results derived from the past 3 years.

21. Power Factor Improvement in the Steel Plant with Advanced AC Drive System

Shah S, Panchal A K and Varsha A Shah

This paper presents the analysis of power factor with DC drive system and AC drive system in one of the major steel plant in India. Replacement of DC drive system with AC drive system have drastically improved power factor of the system. With advanced direct torque control (DTC), performances of AC drives are similar to DC drives in entire speed-torque region. By various comparisons of technical and fi nancial parameters, it is found economical to use AC drives in place of DC drives. AC drives ensure improvements on power factor, energy effi ciency, reliability and production with reduction in cost, maintenance and equipment down time.

After comparing the DC drive system and AC drive system in pickling plant, the power factor improvement observed with AC drive system. The simulation studies also predicted that there will be improvement in average power factor from 0.2~0.65 to 0.93~0.97. Results obtained after replacement of DC drives with AC drives are quite matching with the predicted results. In addition, AC drive system also helped in energy saving and reduction in line stoppage occurrences.


ABSTRACT LIST


1. Dynamic Compensation Studies using RTDS for Large Wind Farm Integration with Grid

Meera K S and Shivakumara Aradhya R S

Amongst all renewable energy sources so far identifi ed in India for commercial exploitation, wind energy is the one, which has been found to be more viable for generation of grid quality power. Following recent growth of wind generation, utilities have responded by developing various interconnection requirements/guidelines to which the wind farm must abide. The guidelines provide for penalty to be levied by State Electricity Boards, if the projects fail to achieve minimum monthly average power factor of specifi ed value at the coupling point. Suitable penalties are also levied for reactive power to discourage drawl of reactive power from the grid and to avoid free wheeling of the machine.

Majority of wind generator topologies are asynchronous machines, which draws reactive power from the grid. Thus, there is a requirement that the wind farms be self suffi cient with respect to the needs of reactive power of the wind farm. The methods of reactive power control may be provided in the form of capacitor banks, static power converter based devices (SVC, TSC, or STATCOM) or by employing machines capable of reactive power control, such as the doubly-fed induction machine topology.

This paper discusses the results of grid integration studies of wind farms, based on three phase dynamic simulation utilizing the real time digital simulator (RTDS). It investigates the application of STATCOM for a typical wind farm for providing an effective means in dynamic voltage control of the wind farm, meet the reactive power requirements of the wind farm and enhance the capability of the wind farm to ride through the grid disturbances.

2. Reliable Control Strategy related to Hybrid Eenergy System for On-Grid Electrifi cation of Villages in Weak-Grid Environment

Prashant Pandya and Ranjit Roy

Method for on-grid electrifi cation of villages. An improved control strategy is incorporated which enable the system to switch on in to grid and whenever required it can be set back to a micro grid. The studies are simulated in time-domain discrete mode using MATLABTM/SimulinkTM. Wind-fuel cell based hybrid energy system is tested with all possible control parameters and it is observed that the proposed control strategy is working satisfactorily.


3 Distributed Generation and its Impact on Power System

Grishma Patel

The penetration of distributed generation (DG) into the main electricity network is changing the paradigm we used to live with. DG is gaining interest worldwide as numerous benefi ts are associated with this change due to penetration of DG. In this paper the main purpose is to show the basics of distributed generation. The different ways to interface the DG with the utility system are also reported. Penetration of a DG into an existing distribution system has many impacts on the system and equipment operations in terms of steady-state operation, dynamic operation, reliability, power quality, stability and safety for both customers and electricity suppliers. However here in this paper the more focus in on impact of DG on power quality pointing out its positive and negative impacts and its solutions. At last to support this arguments analysis of results are shown which are directly taken from the references, where the results revels the effect of DG on power quality and based on that some conclusions are documented.

4. Swarm Intelligence based Distribution Load Flow Method for Distributed Generation Planning

Naveen Jain, Singh S N and Srivastava S C

This paper presents a new swarm intelligence method of distribution load fl ow (DLF) suitable for systems with distributed generators. The proposed DLF method is able to incorporate all kind of voltage dependent load models. This load fl ow method avoids the problems faced by various methods in handling multiple PV buses and is also suitable for small-scale, medium-scale and large-scale distribution systems. The proposed DLF method is used for placing multiple fi xed standard size capacitors. The optimal sitting and sizing of multiple DGs are also carried out utilizing a system loss reduction criterion. The proposed load fl ow algorithm is tested on distribution systems with fi xed standard size capacitor and/or DG for various load models to show its effectiveness. Some existing DG planning results are compared to show the capability and the accuracy of the proposed algorithm.

5. A Review on Effective Lightning Protection for Wind Turbine Generators

Ashok Kumar L

A wind turbine generator is the most exposed of all types of generators connected to electric utility systems. Wind turbines are most often erected in hostile lightning environments. Lightning damage to wind turbines is costly in terms of repair and replacement of equipment. Lightning damage is the single largest cause of unplanned downtime in wind turbines, and that downtime is responsible for the loss of countless megawatts of power generation. There is currently no international standard governing wind turbine lightning protection. This paper is a review on the available guidelines for effective protection.


6. Computed Lightning Electric Field Ratios of First and Subsequent Return Strokes

Chandrasekaran K and Gururaj S Punekar

Electromagnetic fi elds generated due to ‘typical’ fi rst return stroke (FS) and subsequent lightning return stroke (SS) have been computed and compared. The simulation results are discussed keeping in view the fi eld data reported in several recent literature, which compares the severity of fi rst and subsequent return strokes. The MTLE based engineering model is adopted to compare the severity of lightning return strokes (FS/SS) as a function of radial distance and the worst case ground conductivity.

In general, the magnitude of electric fi eld peak due to of fi rst return stroke is nearly twice that of fi eld peak due to subsequent return stroke as reported in the literature, based on the data collected by lightning detection, information and fi eld measurement systems. The present simulation results not only substantiate this fact but also try and assess few parameters responsible for low ratio of FS/SS (reported in some cases) through simulation process; as causes for these low ratios are yet to fi nd satisfactory explanation.

7. Swarm Intelligence based Approach for the Loss Minimum and Cost Minimum Confi guration of an Interconnected Power System

Vikash Kumar Gupta, Bhattacharyya B and Goswami S K

This paper presents particle swarm optimization (PSO) based approach for the allocation and coordinated operation of multiple FACTS (Flexible AC Transmission System) devices for the economic operation as well as to increase power transfer capacity of an interconnected power system under different loading condition. The PSO based approach is applied on IEEE 30-bus system. The system is reactively loaded starting from base to 200 % of base load. FACTS devices are installed in the different locations of the power system and system performance is noticed with and without FACTS devices. First, the locations, where the FACTS devices to be placed is determined by calculating active and reactive power fl ows in the lines. A PSO based algorithm is then applied to fi nd the amount of magnitudes of the FACTS devices. This PSO based approach for the placement of FACTS devices yields promising result both in terms of performance and economy which is clearly observed from the results obtained.

8. ANN Based Adaptive Relaying Scheme for Protection of Active Distribution Networks

Raghavendra G, Nagaraja R and Khincha H P

This paper presents a new adaptive relaying scheme for the protection of active distribution networks, i.e. protection of distribution networks connected with distributed generation/dispersed generation (DG). The traditionally radial distribution systems may no longer be radial in the presence of DGs, which can hinder the existing co-ordination between the protective relays. This paper addresses the relay co-ordination issues encountered due to the presence of DGs in the network and explores the application of Artifi cial Neural Networks (ANNs) as a solution for the protection of active distribution networks. The proposed method, based on ANN, shows that the issues regarding relay co-ordination can be overcome and only the faulted section can be isolated precisely.


9. Supervised Tripping and Blocking of Distance Relays

Raghavendra G, Faraz Z Khan, Nagaraja R and Khincha H P

This paper introduces a new scheme for supervised tripping and blocking of distance relays using the data from phasor measurement units (PMUs). The proposed scheme utilizes fault detection, double ended fault location algorithm and expert system rule sets to arrive at a decision whether to trip or block the backup protection. Conventional distance relays encounter challenges in the form of parallel line operation, mutual coupling effect, fault resistance etc. These issues are well addressed by the proposed scheme in a reliable manner and the concept is supported by the case studies.

10. Sub-synchronous Resonance through Torsional Mode Interactions: An Analysis

Shashidhara M Kotian, Sreenadh Batchu and Shubhanga K N

Interaction between electrical and mechanical systems, generally termed as sub-synchronous resonance (SSR) in power system, is not a straightforward problem to analyze as it involves detailed modeling of both systems. From the literature it is found that in most of the cases the SSR analysis is demonstrated through the IEEE fi rst-benchmark system which contains many intricate modal interactions. To motivate the students to take up such standard systems for analysis, in this paper an example is presented which brings out the issues associated with the analysis by employing simplifi ed models for generator and mechanical systems. Model and design equations are systematically derived so that any variations can be tried with ease. Case studies are presented to demonstrate the concept of modal interactions by studying the systems both in isolation and in combination. Eigenvalue analysis is carried out in addition to time-domain simulation to show that SSR is purely a discrete event.

11. Effective Location of SVC Controller for Small Signal Stability Enhancement in Multi Machine Power Systems

Senthil Kumar N

The problem of small signal stability is usually due to insuffi cient damping of system oscillations. The power electronic based FACTS devices are effective for system voltage control and power fl ow control. This paper presents a systematic method of developing the small signal model for stability enhancement in a power system using SVC. While the primary purpose of a Static Var Compensator (SVC) is to regulate bus voltage, it can also improve stability and damping of a power system if located appropriately. This paper proposes a Residue factor to fi nd the location of SVC in multi-machine system. The proposed residue factor was based on the relative participation of the parameters of SVC controller to the critical oscillatory mode. The algorithmic steps for computing the residue factor is proposed, which combined the linearized differential algebraic equation (DAE) model of the power system and the SVC output equations. The effectiveness of the proposed method was demonstrated on the standard WSCC 3 Machine 9-Bus system. All computations were carried out using MATLABTM v7.6.


12. Control of Harmonics Generated by Alternating Current Electric Arc Furance and Laddle Furnace

Rajashekar P Mandi, Janak J Patel, Hitesh R Jariwala and Ankur Vashi

An arc of an electric arc furnace as a virtual short circuit is purely resistive load but the reactor connected in series with primary of furnace transformer to smoothen the arc makes the total combination as an inductive load, with its fl uctuating active and reactive power requirements, it leads to power quality issues such as poor power factor, harmonic generation, etc. This paper presents measurement and analysis of harmonics generated by alternate current electric arc furnace (AC EAF) and laddle furnace (LF) loads and also defi nes terms like harmonics, total harmonic distortion etc. Harmonic Filter Banks (HFB) of static Var compensator (SVC) are tuned to particular order of frequency to provide least resistance path to that order of harmonics for elimination. This paper also describes design criteria for harmonic fi lter banks of 100 Hz, 150 Hz and 200 Hz and presents the SVC as a solution for control of harmonics. The fi nal results are compared with allowable limits set by international standards.

13. Comparison of Alternate Current Electric Arc Furnace with Direct Current Electric Arc Furnace with their Static Var Compensator confi gurations

Rajashekar P Mandi, Janak J Patel, Hitesh R Jariwala and Ankur Vashi

An electric arc is purely resistive load, but the series connected reactor to smoothen the arc makes the combination inductive load creating power quality issues like harmonic generation, poor power factor, voltage fl ickers etc. An electric arc furnace is heart of integrated steel plant used for smelting of steel with help of electric arc. Temperatures insider the furnace can reach up to 1800° centigrade and capacity wise electric arc furnaces are available from 1–300 tonnes. The charged material is directly exposed to the electric arc and results into hot liquid steel. The charged material can be steel scrap, direct reduced iron and hot metal. The electric arc furnace can be classifi ed as alternate current electric arc furnace (AC EAF) and direct current electric arc furnace (DC EAF) depending upon source of power used at furnace for arcing. The objective of this review is to compare the confi guration and harmonics generated by operation of AC EAF and DC EAF. Static Var compensator (SVC) is solution to mitigate the power quality issues generated by the electric arc furnace. This review also compares confi gurations of the SVCs used for AC EAF and DC EAF.

14. Reactive Power Management Practices and their Comprehensive Evaluation for a Short Circuit Test Plant

Venkateswarlu G, Mondal N R, Ansari M A and Raghavaiah B V

A vast majority of electrical loads in short circuit testing plants are inductive rapidly varying in nature. Typical examples are motors, transformers, drives etc. Such loads consume high reactive power in short durations. Load requirement of the short circuit plant is intermittent in nature due to varieties of customer tests. Hence controlling of reactive power of these types of loads is a challenge. It is therefore necessary to reduce and manage the fl ow of reactive power to achieve higher effi ciency of the short circuit plant and reduction in cost of electricity consumed. An improvement of the reactive power management of an installation presents several technical and economic advantages, notably in the reduction of electricity charges. This paper discusses a cost effective method of reducing and managing reactive power. It has been shown that the installed reactive power compensating devices captured both the technical and economic aspects of short circuit plant operation in competitive electricity markets. Also it has been shown that traditional techniques are economically viable if they are used in a judicious manner.


15. Five-Limbed Transformer Cores

Sankar V

There are many fi ve limbed core confi gurations. In all the existing confi gurations specifi c loss (loss per kg at a given fl ux density) is higher than the three phase three legged core. The reasons are yoke areas not matching with the amount of the fl ux fl owing and the mitered joints also not matching with the quantity of the fl ux fl owing. Compared to the non-split cores, the split cores are posing manufacturing problems and higher losses. Model core of a new confi guration and two model cores of existing confi gurations were built and tested. Relative merits of the new core confi guration and reduction in losses are tabulated. This new core confi guration can be adopted easily for both non-split and split cores. Relative advantages and disadvantages of different core confi gurations are discussed.

Tests conducted on model cores described in this paper are limited to fi ve-limbed core type transformer cores. Iron losses were measured at different fl ux densities on model fi ve-limbed cores with different core confi gurations. The fi rst model (Type 1) is the typical confi guration being used by transformer manufacturers around the world. An attempt is made to build another model fi ve-limbed core (Type 2) by modifying the position of mitered joints of main end limbs laminations. This modifi cation was done so that the fl ux from the main end limbs can fl ow from limbs to yokes without overcrowding at mitered joints. Often, the diameter of the main limbs is greater than the maximum widest width lamination normally available (1000 mm). For this reason, fi ve-limbed cores often have split limbs. A third model (Type 3) representing the split core was also built to get a loss comparison with non-split cores.

16. Finite Element Analysis of Transformer Clamping Structure to Study Effect of Copper Shield on Structural Losses and Winding Eddy Losses

Ram Krishna Mishra and Saravanan Selvaraj

The losses due to transformer leakage fi eld comprise a small percentage of the power in a transformer. Yet these losses produce localized heating which can compromise its operation. The stray fi eld strength increases rapidly with growing rating. The stray fl ux intruding into the structural parts gives rise to eddy currents in them. The resulting eddy current losses may be considerable, thereby increasing the load loss of transformer [1, 5]. The objective of this work is to calculate stray losses in magnetic structures of 400 MVA 1-phase, 500–230 kV auto transformer and study the effect of copper shield on structural losses and winding eddy losses, using commercial software package Magnet (Infolytica Corp.) based on fi nite element method (FEM). Due to presence of non linear magnetic materials, the sinusoidal source with 60 Hz frequency induces non-sinusoidally varying magnetic fi elds. A transient solution (which calculates time varying magnetic fi eld) is required for calculating fi elds in non-linear materials. However, this requires more computational resources. Therefore Time harmonic solution (which calculates fi eld at 60 Hz frequency) with linear magnetic materials is used for this analyses. Further, 3D time harmonic analysis has been done to analyze the effect of varying Cu shield thickness on loss density and fi nally its effect on winding eddy losses has been investigated.


17. Prominence of Magnetic Properties in Grain Oriented and Non-Grain Oriented Steels for Transformer Industry

Arjuna Rao S, Swaraj Kumar Das and Raghavaiah B V

Cold rolled grain oriented (CRGO) electrical steel is a critical raw material for manufacturing of transformers, which is fully imported as it is not manufactured in India. Currently India consumes about 2.5 lakh metric tonne per annum of CRGO electrical steel and with the growth in demand of transformation capacity the consumption is estimated to be 11.5 lakh metric tonne and 13.5 lakh metric tonne respectively during the 12th and 13th fi ve-year plan period. Magnetic cores for the wide range of modern electrical and electronic devices require magnetic materials with many combinations of properties and characteristics. The evaluation of magnetic core materials is very crucial before using for transformers, motors and Inductors.

18. Quantitative Analysis Ageing Status of Insulation of High Voltage Motors by Polarization – Depolarization Current Measurements

Tapan M Rami and Dipak Mehta

Polarization and depolarization current (PDC) technique is an effective tool to assess the condition of insulation system in high voltage motors So far the PDC behaviors of insulation have been widely investigated. This Paper presents the assessment of insulation systems for high voltage induction motor through measurement of polarization depolarization current or charging and discharging current. However, with the increasing number of Motors choosing insulation , it is important to investigate the PDC characteristics of insulation to see whether the PDC technique can also be used to assess the condition of new insulation system using PDC accurately It is considered that the insulation systems are having different types and conditions of insulation aging. It demonstrates that the insulation resistance (IR) and polarization index (PI) can’t be used individually to judge insulation dryness and the combination of insulation resistance and PI. PDC analysis is better technique of insulation quality assessment than the insulation resistance alone. The PDC analysis is non destructive dielectric testing method for determining the conductivity and moisture content of insulation materials in high voltage motors. On the basis of this analysis, it is possible to take further actions like overhauling, drying process, and replacement of the winding of the motor. This paper also presents a description of PDC analysis technique with the practically and theoretical background and some results of PDC measurements on High voltage motor duration from 0–600 days.


19. A Study on Integration of Acetone Charged Copper Pipes (ACCP) to MR16 Indoor Lighting Solutions

Gopalakrishna K, Krishna Venkatesh, Rama Narasimha K, Ananda M A, Parasuram A K, Gururaja G, Jayaprakash P N and Sendil Kumar T J

The aim of the present study is to improve the thermal performance of the MR16, 7 W and 9 W LED decorative lighting solutions by integration of acetone charged copper pipe (ACCP) into its aluminum heat sink. With integration of ACCP, the luminary designed for lower wattage can withstand higher wattage and can accommodate more LED’s with increased illumination. The heat transfer characteristics of high power LED is analyzed and a novel ACCP cooling device for high power LED is designed. The thermal capabilities of lighting solutions with integration of ACCP and without integration of ACCP for the same load (fi xture + heat sink) were investigated experimentally. The experimental results indicate that the given load can accommodate more LED’s for higher wattage which can be attributed to improved heat transfer after integration of ACCPs resulting in increased illumination.

20. Investigation of Mechanical Properties and wear behavior of Ni-alloyed Specially Heat Treated Permanent Moulded Austempered Ductile Iron (PMADI) for Power Plant Applications

Sethuram D and Narasimha Murthy K

Austempered ductile iron (ADI) is relatively newer material, which has attracted researchers and manufacturers alike mainly because of its immense properties and also at the same time cheaper to process and produce. Utilization of permanent moulds to ADI has many advantages such as very good dimensional stability, good nodule size count, better surface fi nish and environmental cleanness. Extensive literature survey reported that ADI out-performs proprietary abrasion resistant steels at similar bulk hardness levels.

Experiments were systematically planned to study the mechanical and wear properties of Ni-alloyed PMADI and are processed by a novel two step austempering process. All specimens were initially austenitized at 950 °C for 2 h. These samples were initially quenched for 5 min in a salt bath maintained at 250° C and then austempered for 2 h at several austempering temperatures. These temperatures were 280° C, 310° C, 340° C, 370° C, 400° C, and 430° C. The results show that this novel process has resulted in higher tensile strength, yield strength, hardness and wear resistance than the conventional single step austempering process. The tensile strength value improved by about 11% for 2% Ni PMADI samples over 1.5% i PMADI samples while maintaining reasonable levels of ductility. The results are analyzed based on the micro structural features.


21. Corrosion Behaviour of Aluminium Alloy-Flyash Composites used in ESP

Suresh N, Venkateswaran S, Seetharamu S, Sampath Kumaran, Ramachandran B E and Praveen Kumar T N

The effect of corrosion on aluminium alloy (LM6) containing ceramic fl y ash based microspheres is investigated in this work. Stir casting route has been employed to disperse 10 % ceramic microspheres as reinforcement in the alloy matrix. Further, the alloy system was subjected to grain refi nement, modifi cation as well as combined action of grain refi nement and modifi cation. Three sets of LM6 alloy castings were produced in each case, to check for reproducibility. The corrosion resistance was evaluated by immersing the samples in 3% NaCl solution. The pH and electrical conductivity were measured to assess the damage due to corrosion. It was observed that the corrosion resistance decreased in the composite samples subjected to grain refi nement, modifi cation, combined action of grain refi nement and modifi cation compared to untreated alloy composite. Scanning Electron Microscopy [SEM] has been used to substantiate the corrosion data. On the other hand, mechanical properties namely hardness and ultimate tensile strength improved greatly in the modifi ed samples compared to grain refi ned and grain refi ned and modifi ed samples.

Vol. 9, No. 2, June 2013

ABSTRACT LIST

THE JOURNAL OF CPRI - Vol. 9, No. 2, June 2013

1. Investigation on Flashover Performance of 25 kV Traction System Section Insulator Assembly in DMRCL System

Dharmesh Y, Vasudev N, Karunakara K, Sheshagiri Rao U R, Shivakumara Aradhya R S, Anoop Kumar Gupta and Mukesh Wadhwa

This paper describes the failure analysis of a section insulator assembly at one of the depot of Delhi Metro Rail Corporation Limited (DMRCL). Frequent breaker tripping at Saritavihar depot of DMRCL due to flashover of the section insulator assembly was observed; the cause of failure of the section insulator was investigated and presented in this paper. As a first step laboratory tests on new and used section insulator assemblies were conducted to make comparative analysis, and then simulation studies were carried out to estimate the possible over voltages during different switching operations and their relationship with the test voltages used in the experimental investigation. This paper presents the laboratory experiments and simulation studies for the failure analysis of section insulator assembly of DMRCL.

2. Types of Power Quality Disturbances on AC Electric Traction Drives: A Survey

Mohan Krishna S

Modern electric traction drive systems make use of power electronic devices which directly affect its performance and efficiency. Numerous power quality phenomena are associated namely: Voltage flicker, Harmonic voltage and current distortion, voltage dip, transient over voltages, voltage and current unbalances. It is important to emphasize the fact that all the above mentioned phenomena appear due to the non linearity of the loads, who by themselves act as harmonic current generators. This paper gives a brief overview of the power quality disturbances which cause significant impact on the traction drive system as well as the supply side.

Vol. 9, No. 2, June 2013

3. SignificanceofSupportStructureforShortCircuitwithstandStrengthof Bus-bar Assembly Panels - Experiences with Testing

Maheswara Rao N, Girija G, Vasudevamurthy B R and Swaraj Kumar Das

This paper describes short circuit withstand capability of Bus-bar assembly panels and the significance of Bus-bar support structures commercially available in use. Recent developments in Bus-bar support structures for assembly panels are also discussed. The performance comparisons of these support structures under the Short-circuit currents were given. Few failure cases are studied from the laboratory tested panels and appropriate recommendations were proposed. This can give an insight, while selecting the suitable bus-bars support structure. Theoretical Force calculations were compared for different Bus-bar geometrical configurations.

4. IdentificationofDynamicCharacteristicsof12kVCircuitBreakerunder EarthquakeLoading

Srujana N, Ramesh Babu R and Katta Venkataramana

History of past earthquakes had demonstrated that structural failures in substations were non- recoverable unless huge amount of money and man power involves in it. A broad range of substation equipment are especially vulnerable to seismic vibrations and circuit breaker is one among them. Failure in circuit breaker results flow of excessive current in substation components than the respective ratings. Excessive current in substation components cause fire accidents along with power outages. The efficient way to resolve the problem is to analyze and identify the failure points over the earthquake vibrations before installing in the field. This paper discusses in relation to earthquake acceleration amplification of 12 kV circuit breaker used in substations. Shake table experiments are conducted on circuit breaker at higher seismic zone levels. The ground motion amplification obtained from finite element analysis and shake table tests is compared.

5. DesignofANewDeregulatedMarketStructureforanIndianGridwith Focus on Different Controllers

Peer Fathima A, Shrinivass A V and Shravanthi R

The main objective of this paper is to create a new deregulated market structure namely Dyadic Market Structure which provides an optimal environment to nurture private sectors and also to protect customer interests. The four area interconnected system (Andhra Pradesh, Karnataka, Kerala and Tamil Nadu) of the Southern Regional Grid is considered as a public sector of this structure and its frequency response is improved by secondary regulation by using various controllers like PI, PID and Fuzzy logic Controllers. The simulation is carried out using MATLAB SIMULINK.

Vol. 9, No. 2, June 2013

6. ImprovementsintheDevelopmentofGridCodeandReviewofPower QualityRequirementsforFluctuatingWindPowerGenerationinIndia

Amuthan N and Subburaj P

This paper deals with the improvements in the Indian grid code and the important point in the power quality requirements. It reviews the Indian grid code and the grid code requirements for wind energy conversion systems and the modifications in the Indian wind energy grid code is presented for further improvements. Power quality issues and requirements in the grid integrations are briefly explained. The main objective of the power quality review is to study the basics of power quality, standards, measurements and the devices used to improve the power quality. The current The International Electrical Commission (IEC) standards were described and the measurements standards are presented. The power quality problems associated with grid integration like voltage fluctuations or flicker; harmonics and interharmonics; voltage drops; active power; reactive power; grid protection and reconnection time are studied and the implementation of the measurement and assessment procedures, specified by the various standards are discussed.

7. LowVoltageRideThroughCapabilityAnalysisofDFIGusingFeed ForwardCurrentRegulator

Bankar D S and Talange D B

In recent years due to increase in the load demand a lot of emphasis is given on the use of non-conventional energy sources since fossil and atomic fuels will not last forever, and that their use contributes to environmental pollution [1]. Out of all non-conventional energy sources wind has been the fastest growing energy source over the last decade mainly due to very significant improvements in wind energy technology. Doubly fed induction generators have become the most popular type of wind turbine generators due to its excellent characteristics of control. But, these types of generators are susceptible to grid-side low voltage faults and short circuits. Power electronics converter connected on the rotor side affects badly under these conditions. When a short circuit or voltage sag occurs on the grid side, the rotor current of the generator tends to rise, which could cause damage to the rotor convert. To overcome this difficulty RSC is disconnected and crow bar is activated thus the DFIG now acts as the conventional induction machine. Grid codes suggest that these plants are required to remain connected to the grid in the event of voltage dip also they should contribute to the power system by feeding the active and reactive power safely [5]. The LVRT requirement is very important as far as grid stability is concern when a large wind farm is connected to the grid. But it is difficult to satisfy for wind plants using DFIG system since the DFIG stator is directly connected to the grid and the rotor is connected through RSC, hence complete DFIG system is much sensitive to grid disturbances [4]. This paper presents the feed forward current regulator for rotor side converter of DFIG and analyses its low voltage ride through capability. The results show that the LVRT capability of doubly fed induction generator has improved.

Vol. 9, No. 2, June 2013

8. TheElectricalVehicletoGrid,it’slikelyImpactonFutureofPowerSystem – A Review Paper

Sudhir Kumar R, Deshpande R A and Kavitha D

Vehicles running on oil have to change over in next few decades to alternatives which could be hydrogen, electricity. World over, almost all the major players in the automobile industry have introduced electric vehicles (EV) or Plug-in Hybrid Electric vehicle (PHEV) in the market. This is rather in response to their commitment to a green environment, reducing carbon footprints and reducing the emission rates. With the unveiling of the National Electric Mobility Mission Plan 2020, by the government of India manufacturers areurged to adopt electric vehicles in an attempt to reduce our dependence on imported oil. The ambitious plan aims to produce 6–7 million electric vehicles by 2020 with an estimated fuel saving of 2.2–2.5 million tonnes of oil. Electric vehicles when utilized for feeding back the energy to the grid play a very important role in Demand response in Smart grid environment. This will play a major role in the Power sector scenario. Though this technology is yet to pick up in India, it has become popular in the western countries. Lot of Research work has been carried out and research work has been published, which is reviewed in this paper.

9. PSObasedMulti-CriteriaPlacementandImpactEvaluationofDistributed GeneratorsinIndianContext

Naveen Jain, Singh S N and Srivastava S C

This paper presents a new approach for optimal placement of Distributed Generators (DGs) utilizing a generic multi-objective performance function considering dynamic relevance (weight) factors and various levels of the DG penetration. The suggested approach can place the fixed size as well as the variable size of multiple DGs in single or multiple stage(s), considering any type of load model. The technical performance of the system, with the dynamic relevance factors is found to be better than with the fixed relevance factors approach. The effect of considering system constraints on the DG size and its location has been studied. A look up table approach is also suggested to place the DG at locations other than the most optimal one. The impact of the DG placement on the system voltage profile and line loss has also been investigated on 33-bus and 41-bus (Indian system) distribution systems. The critical cases with extreme DG output power and distribution load demand are simulated on these systems to study the technical viability of the DG planning under such circumstances.

Vol. 9, No. 2, June 2013

10. DesignandImplementationofMicro-SteppingDriveofStepperMotorfor SolarArrayDriveAssemblyusingFPGA

Sachin Angadi, Satyanarayana Kumari B and Saikumar H V

This paper describes the design of a control system for a micro step driving method of stepper motor using VHDL. The control system so designed is employed in the application of Solar Array Drive Assembly (SADA) in terrestrial solar plant and in satellites. This solution uses a digital controller with Sine-Cosine variation to control the currents of the two phases of the motor, making them change according to the orthogonal sinusoidal scalar form curve, fulfilling the micro step driving of stepper motor and improving its position control precision by hundreds of times. At the same time, this driving method solves problems such as large noise, resonance and non-even step angle and so on. The work presented in this paper implements the control system in Xilinx ISE.

11. CombinedEffectofDeterministicandStochasticVariablesonComparative PerformanceAnalysisof110kWA-SiPVandC-SiPVbasedRooftopGrid TiedSolarPhotovoltaicSystemsinJodhpur

Vikas Pratap Singh, Vivek Vijay, Ravindra B, Chaturvedi D K and Rajashekhar P Mandi

The main objective of this paper is to review the state of the art of IIT Jodhpur Rooftop installed 110 kW PV systems. This is done analyzing the operational data of 110 kW PV systems (43.30 kW located in Block 1 and 58.08 kW in Block 2). Performance analysis depends on three basic term of solar PV. How much energy do they produce? What level of performance is associated to their production? Which are the key parameters that most influence their quality? During the year 2011, the PV systems in Jodhpur, India have produced a mean annual energy of 1290.64 kWh/kWp in block-1 and 1290.64 kWh/kWp in Block-2. As a whole, the location of Solar PV system is the main reason of energy variability and system output. The overall mean Performance Ratio is 75% in both Blocks. Solar power variability depends on the two variables, deterministic and stochastic variable. In last few years researcher work on finding deterministic variable such as system losses (module efficiency, DC cable losses, inverter losses and AC cable losses) but these deterministic variables are not enough to give accurate forecasting so with the help of combined effect of these both variable give accurate plant performance and reliable solar power forecasting for solar power scheduling and dispatchability.

Vol. 9, No. 2, June 2013

12. DynamicSimulationStudyofIGCCPowerPlant:ImpactofCoalFlow Change

Rasesh Kotdawala, Thirugnanam C and Nagaraj Kumar T V S

Coal usage is becoming more widespread in India because coal reserves are much greater than oil and gas reserves combined together and the cost of coal is also very attractive. For reducing the carbon emissions when coal is utilised for power generation, Integrated Gasification Combined Cycle (IGCC) technology can be used, which uses a gasifier to turn solid or somewhat pulverised coal into gaseous form which is called as synthesis gas (syngas). IGCC has the potential to generate power with better efficiency or efficiency on par with the existing technologies. It is very important to understand operational and design aspects of the IGCC technology via dynamic simulation studies. The paper discusses the transient behavior of the commercial scale IGCC plant through dynamic simulation studies. The major components of IGGC plants-gasifier, Heat Recovery Boiler (HRB), syngas clean up system, gas turbine, HRSG and regenerative steam cycle were modeled in Modular Modelling System (MMS). The objective is to study the effect of coal flow to the gasifier on the transient behaviour of the plant parameters.

13. Evaluation of Corrosion Properties of Cenosphere Aluminium Composites

Prashanth T, Narasimha Murthy K and Umesh C K

Industrial processes generate certain solid by-products, the disposal of which is of serious environmental concern. The solid by-products are mainly fly ash from the power generation industry, metallurgical ore residues and slag, slurry from the mining industry, etc. Among these, fly-ash utilization continues to be an important area of national concern due to India’s dependence on thermal power generation for its energy supply. Particle reinforced Al matrix composites are emerging out as potential materials to replace conventional alloys/metals. These metal matrix composites (MMCs) find extensive applications in many engineering activities because of their lightweight, high stiffness and high specific strength. This paper discusses the manufacture of cenosphere-aluminium composites. Based on varied ratios of the reinforcement phase, fly-ash cenospheres – 6061 aluminium composite with better features in terms of strength, corrosion resistance and hardness and has been developed. The current work also brings out the structure – property correlation of cenosphere-aluminium metal matrix composite. It is found from the microstructure studies that there is a homogeneous distribution of the cenospheres in the matrix of Al 6061. The corrosion studies show that there is an increase in the corrosion pitting of the cenosphere-aluminium composite.

Vol. 9, No. 2, June 2013

14. InfluenceofNickelonAbrasionandErosionWearBehaviorofThinand ThickSectionPermanentMoldedAustemperedDuctileIronforWind Turbine Hubs

Narasimha Murthy K, Sampathkumaran P, Seetharamu S and Kumar R K

The influence of 2.0% nickel on thin and section permanent molded austempered ductile iron samples were investigated for abrasion and erosion behavior. The section sizes of samples were varied at two levels viz. 25 mm and 50 mm. Wind turbine hubs which were subjected to wear and erosion were made from thin and thick section PMADI castings. The austempering temperature and time were optimized for improved wear behavior and strength at 3000 C for 60 mins. Nickel additions showed about 7% improvement in the wear resistance of thin section PMADI samples over unalloyed PMADI samples. For the purpose of comparison, sand-cast austempered ductile iron was also evaluated for abrasion, erosion resistance. Thin section (25 mm) PMADI samples subjected to austempering at 3000 C for 60 mins showed improved abrasion and erosion behavior in addition to higher strength values over thick section (50 mm) PMADI and sand cast ADI samples. Further these data were analyzed with structure property correlation and were well supported by light photomicrographs.


ABSTRACT LIST


1. Fuzzy Logic based Short Term Load Forecasting

Amit Jain and Santosh Kumar Kukkadapu

With increasing complexity of modern power systems, good quality load forecasting has become the necessary requirement for secure and reliable operation of power grid. Short term load forecasting plays vital role in daily operation of power grid to provide right inputs for the commitment of power generation units and dispatch. Fuzzy logic based short term load forecasting is described in this paper. To obtain the next-day load forecast, fuzzy logic is used to modify the load curves on selected similar days. A new Euclidean norm with weight factors is used for the selection of similar days. The proposed fuzzy logic based short term load forecasting method presented in the paper is illustrated through the simulation results on a typical data set.

2. Placement of Distributed Generation in 33/11 kV Radial Distribution SystemtoMinimizePowerLosses,ImprovementinVoltageProfileand Reliability using Genetic Algorithm

K Amaresh and V Sankar

Integration of renewable energy based distributed generation units provide potential benefits to conventional distribution systems. The power injections from renewable DG units located close to the load centers provide an opportunity for system voltage support, reduction in energy losses and reliability improvement. Therefore, the allocation of DG units should be carefully determined with the consideration of different planning incentives. In this paper, a simple method for real power loss reduction, voltage profile improvement which is based on voltage sensitivity index analysis is considered. Power flow analysis is done using the forward-backward sweep method, the placement and sizing of DG in distribution system are determined using optimization.The objective is to improve the reliability indices. The placement and size of DGs are optimized using a Genetic Algorithm. To evaluate the proposed algorithm, the 10 bus distribution feeder is used. The results illustrate the efficiency of the proposed method.


3. Predictive Reliability Assessment in the Power Distribution System

K V Harikrishna, V Ashok, P Chandrasekhar, T Raghunatha and R A Deshpande

The electrical utilities are facing market conditions and therefore have to plan and operate their distribution systems in a cost effective way. This implies that the customer’s requirement on reliability i.e. availability has to be balanced towards the cost for obtaining the same. An effective way to solving this issue is by the use of quantitative assessment of reliability, i.e. reliability indices, which is based on probability theory. However these methods require input data that defines the condition for the system and its components. is to predict the future behaviour based on collected data and measured performance.

The reliability assessment is normally used to evaluate performance of the distribution system network. The reliability of power Distribution system can be calculated by different reliability indices.This paper describes the reliability indices for two feeders of one is an industrial feeder and another one is an urban feeder. A software module (Reliability Assessment Module-RAM) has been used and the results of two practical distribution feeders are compared to benchmark the performance and operation of the power distribution system.

4. Analysis on Emerging Trends and Challenges in Smart Grid Automation Technology from Generation to Distribution

Balakrishna P, Rajagopal K and Swarup K S

Power System or Grid is defined as the collection of group of devices, components that make a physical system to generate, transmit and distribute electricity to the end users. Complexity of power system has grown tremendously in the last few decades, facing new challenges during its operation. In order to meet some of these challenges there is a definite need of automation which helps in automatically operating & controlling the power system under various circumstances. The new era of smart grid in the 21st century has made automation really a need to operate grid under the dynamics of rapid load changes, makingthe system more time sensitive towards faults and failure modes. Automation being one of the critical components in realizing smart grid, this paper tries to present an overview of grid automationtechnology trendfrom generation to distribution over the past few years andfuture opportunities& challenges.


5. Switching Transient Mitigation By Controlled Switching: A Literature Survey

Anjani Pandharkar, T N Date, B E Kushare

Energy is one of the major inputs for the economic development of any country. This is the reason electrical power system network is expanding day by day to serve the increasing energy demand of the nation. There are many types of equipments in power system.A circuit breaker is protective switching equipment and hence, it plays a very important role in the power system. To maintain the adequate reactive power for voltage control in EHV & UHV system, frequent switching of capacitors and reactors is required through circuit breaker.These are the few applications where switching transients can occur frequently.Apart from this unloaded transformer and transmission line energization also leads to inrush current and over voltages in the system. This condition results into electrical and mechanical stresses and sometimes may lead to equipment failure. Controlled switching has become an economical and technically viable solution to reduce switching transients. This paper presents a literature survey based on switching transients and controlled switching aspects.IEEE transactions,conferences, CIGRE reports andvarious catalogues of the controllers are referred for the literature survey. This survey ishelpful for the researchers working in the area of controlled switching, circuit breaker manufacturers,controller manufactures and power utilities.

6. Diagnostic Field Testing and Condition Assessment of Power Transformers in Service

K Mallikarjunappa, Chandrashekar D Keri, V Vaidyanathan, T R Afzal Ahmed, Dillip Kumar Puhan

In this era of reformation, liberalization and unbundling of electricity markets, asset management in power sector has assumed greater prominence. Power transformers are key components in any transmission & distribution network and loss of a transformer can have an enormous impact on reliability and availability of power supply and on cost. As society is more and more dependent on electricity for development, the utilities are under pressure to meet the ever-growing demands for reliable power supply. Economic factors are the main consideration and in order to minimize capital expenditure on new equipment, it is a common policy among utilities to maximize the use of existing networks by operating at their design capability. This can be achieved by according importance to the maintenance practice. A survey of the literature indicates that there are more failures of transformer due to poor maintenance, improper operation, severe weather conditions and manufacturing and design defects than due to insulation ageing. The utilities shall have a systematic O & M practice that include diagnostic tests for condition assessment and health checkup of the equipment. The objective of the condition monitoring tests is to detect the first symptoms of incipient faults, ageing development or other problems and monitor their evolution to enable the operator to take appropriate action to avoid major failure. The paper reviews the results of various diagnostic tests including dielectric response methods for condition assessment of power transformers.


7. Review of Power Transformer Mechanical Condition Assessment Techniques

Shubhangi Patil, B E Kushare

Today’s trend of global electricity market has created a competitive environment in power industry. To reduce operational cost, optimize usage of critical equipments, to improve reliability and customer service, fast and enhanced diagnostic techniques are being developed and utilized in power industry. In recent years, transformer fault diagnosis has become an interesting research area.This paper presents the literature review done in the area of power transformer designs, failure causes and effects and on existing and new diagnostic techniques to generate the baseline for the development of mechanical condition assessment system. The survey has included the 90technical reports and papers from CIGRE, IEEE transactions and conferences along with standards and books based on power transformer conditioning and monitoring. In this paper an attempt has been made to analyze, generate real data based approach for development of enhanced and automated diagnostic system for mechanical faults detection.

8. Modeling, Control and Maximum Power Point Tracking (MPPT) for optimal Battery charging from Solar Photovoltaic (SPV) system

H S Sudhakar, Gujjala B Balaraju, K Pradeep, M Siddhartha Bhatt

MPPT algorithms are necessary in PV applications because the MPP of a solar panel varies with the irradiation and temperature, so the use of MPPT algorithms is required in order to obtain the maximum power from a solar array.Over the past decades many methods to find the MPP have been developed and published. These techniques differ in many aspects such as required sensors, complexity, cost, range of effectiveness, convergence speed, correct tracking when irradiation and/or temperature change, hardware needed for the implementation or popularity, among others. Among these techniques, the P&O and the InCond algorithms are the most common. These techniques have the advantage of an easy implementation but they also have drawbacks, as will be shown later. Other techniques based on different principles are fuzzy logic control, neural network, fractional open circuit voltage or short circuit current, current sweep, etc. Most of these methods yield a local maximum and some, like the fractional open circuit voltage or short circuit current, give an approximated MPP, not the exact one. In normal conditions the V-P curve has only one maximum, so it is not a problem. However, if the PV array is partially shaded, there are multiple maxima in these curves.

9. Application of Synchronised Phasor Measurement Technology in Renewable Energy Systems

K Sornalatha, N Rajkumar, K Pradeep, C Viswanatha, Giridhar P Kini

This paper throws light on application of synchronised phasor measurement in renewable energy systems. Power generation from renewable energy system connected to the grid is highly dynamic, nonlinear which needs to be monitored continuously for efficient and reliable system. There are various methods of monitoring of power from renewable energy system to grid. Nowadays, Time synchronisedphasormeasuring method proves to be a revolutionary method for power system monitoring. Synchronised PMU has wide application such as wide area monitoring, Real time monitoring, post even analysis, visualization, state estimation etc. They are employed in micro grid and distributed generation plants mainly for solving islanding issues. This paper summarises the synchrophasor application and its future scope in renewable energy system.

10. Z-Source Inverter for Maximum Power Tracking in Solar Photovoltaic System

K J Shruthi, Rajashekar P Mandi, C Viswanatha, Giridhar P Kini

This paper discusses the various inverter topologies used in solar photovoltaic system for electrical energy. This paper gives comparison between the conventional type of inverters i.e. voltage source inverter (VSI) and current source inverter (CSI) .New z-source inverter topology is proposed which will overcome the drawbacks in VSI and CSI. Pulse width modulated (PWM) signals are generated for the power semiconductor switches of the z-source inverter for controlling the power to the grid. The characteristics of this inverter are used to obtain maximum power tracking control and delivering to the grid.

11. Load Emulators for Testing of Power Supplies - A Review

Vani Vijay, Giridhar P Kini, C Viswanatha, S JothiBasu

All newly designed power electronic equipments are to be tested as per the standards, so as to verify the response of the equipment under various load conditions. For this, different linear, non-linear and dynamic loads are to be applied to the equipment in accordance with the applications. Load emulation is the process by which the actual load is replaced by a flexible system which can mimic the characteristics of the actual load. A regenerative operation can be implemented in power electronic emulators. Thus by using load emulators for testing, the energy lost in testing of equipments can be reduced to a great extent. Here a review of various types of load emulators is presented which are intended for various types of applications along with some experimental results obtained in various research studies.



12. Analysis of Solar Power Variability Due to Seasonal Variation and its ForecastingforJodhpurRegionUsingArtificialNeuralNetwork

Vikas Pratap Singh, Vivek Vijay, S H Gaurishankar, D K Chaturvedi, N Rajkumar

In 21st century solar power variability is an important issue due to grid integration. In these days grid integration is very popular because of heavy load. So solar power, wind power and conventional power are basic sources of grid integration. Solar power is playing a key role in grid integration. The main objective of this paper is to analyse solar power variability due to seasonal variation in Jodhpur. Jodhpur is known as sun-city for an average 320 sunny days in a year. Average solar insolation available in Jodhpur city is 5.7-6.0 kWh/m2 per day. This is second highest insolation in the world. In this paper, the Solar power variability analysis is carried out based on the data collected from a typical 43 kW amorphous silicon solar photovoltaic system installed in Jodhpur. Mansoon, winter and summer seasons are used for analysis of variation in Photovoltaic Generation due to change of solar insolation. Output of solar photovoltaic system depends on solar insolation and in this paper we have analysed the variation in solar power according to rainy, winter and summer seasons and used artificial neural network to predict the power output from PV system. The paper showed that proposed ANN model is more accurate and study of variability in solar power can help in plant operation, power scheduling and dispatchability.

13. Grid Stability and Control in DFIG Wind Turbines using Dynamic Voltage Restorer

S Arjuna Rao, Swaraj Kumar Das and B V Raghavaiah

The development of wind power in India began in the 1990s, and has significantly increased in the last few years.India has the fifth largest installed wind power capacity in the world.As of 31 Jan 2013 the installed capacity of wind power in India was 18551.7 MW, mainly spread across Tamil Nadu (7134 MW), Gujarat (2,884 MW), &Maharashtra (2310.70 MW)whichare leading the top. All across the world, the demand for electricity from renewable energies is constantly growing. To meet this demand, wind farms must be as operable as conventional power plants and better integrated into the grid control mechanism. Our wind power plants should actively support the grid, fulfilling all necessary requirements and ensuring reliable energy supplies even during breakdowns. Wind power plants feed the grid with controlled reactive power. This allows for a constant voltage control, sustaining the line voltage. Even at temporary voltage dips the wind power plant remains connected to the grid and helps to keep it stable. If any frequency fluctuations occur the effective power of our wind turbines should automatically adjust according to the needs.

14. Shake Table Experiments of Surge Arrester for EvaluationofGroundMotionAmplification

N Srujana, R Panneer Selvam, R Ramesh Babu, Katta Venkataramana

The support structure of a surge arrester within the substation is considered for the experimental and finite element study. Support structures are generally used in a substation mainly for the electrical ground clearance purposes but also it protects the mounting equipment with respect to earthquake loads. The paper is aimed to find out the acceleration amplification levels at base of the support structure at severe earthquake loadings even when it is mounted on steel support structures. Seismic tests are carried out experimentally on shake table. The behavior of the support structure is found satisfactory. No material losses are resulted. Finite element studies are also included in the paper. The finite element model predictions are agreeable to the experimental results.

15. Safe Method to Erect Towers with Electro-Rheological Fluids

Kalyana Sundaram, Ameya V Datrange, Ranjit Patil, Prashant Ravella, Sandeep Mungala

Power sector is one of the fastest growing sectors expanding to remote and inaccessible sections of the Indian Subcontinent. High customer expectations of uninterrupted power supply exist even during occurrence of natural calamities via the distribution and transmission networks. It is a challenge to erect any tower in a short period. Erection of towers involves safety issues of the workmen falling down. Hence there is a need to look at non acrophobic devices such as telescopic towers which can be operated from close to the ground level. Our paper here describes one method to address such a challenge whereby a tower could be constructed quickly without the need of support scaffolding arrangements and without the need for workmen to suffer batophobia.



ABSTRACT LIST


1. Transients Instability Detection and Prevention Control Schemes

Parvathi S and Shanti Swarup K

Effective real time monitoring and analysis of power system has become very important from the point of view of power system stability and security. Recent research in literature has identified that it is possible to determine the critical group of generators and hence predict the generators going out of synchronism. However, a clear mitigation scheme from a wide area perspective has not yet been identified. The main contribution of this paper deals with the post prediction of instability phase. After the identification of the critical generator or group of generators, effective actions such as load shedding should be initiated. The work targets in finding the optimal location where load is to be shed using the rotor angle algorithm and the Jacobian based distribution factor sensitivity

2. Fuzzy Logic Based UPFC Controller for Damping Power System Oscillations

Senthil Kumar N

In this paper, a fuzzy logic controller is proposed for a Unified Power Flow Controller (UPFC) installed in a single-machine infinite-bus power system. The Fuzzy Logic controller is mainly equipped to damp power system oscillations. Simple Fuzzy Logic controller using mamdani-type inference system is used. The Fuzzy Logic based UPFC controller is designed by selecting appropriate controller parameters based on the knowledge of the power system performance. The effectiveness of the new controller is demonstrated through time-domain simulation studies. By comparison, it can be seen that the proposed UPFC controller can provide good performance for different operating conditions of power system. The results of these studies show that the designed controller is robust enough to damp power system oscillations with change in system operating conditions.

3. Energy Storage Sizing to Improve the Distribution Line Performance

Mahesh H Pandya and Mohan V Aware

This paper presents a sizing methodology and optimal operating strategy for a battery energy storage system (BESS) to improve the operating efficiency of distributed networks. The alternate solution to network reinforcement is given by providing the optimal energy storage device. The targeted issues of loss reduction and possible local voltage control are investigated. The relation of feeder losses with requirements of the energy storage requirements are presented through mathematical modeling with actual distribution network parameters. This investigation is carried out with different types of the feeders viz. urban, rural and industrial. The case studies are presented with actual site data obtained from the Maharashtra State Distribution Company of India.


4. Short Term Load Forecasting using Soft Computing Techniques

Chaturvedi D K, Sinha A P and Vikas Pratap Singh

Soft computing techniques are extensively used for electrical load forecasting in the past such as ANN, Fuzzy Systems, GA etc.. ANN has some limitations, such unknown structure of ANN, Decision of neuron type, problem of training data and time, stuck in local minima etc. To overcome the drawbacks of ANN, a Generalized Neural Network (GNN) has been proposed. In this paper, different variants of GNN have been proposed to improve its performance such as GNN integrated with wavelet transform and trained with adaptive genetic algorithm and fuzzy system to forecast the short term week day electrical load. Performance of the proposed algorithm is compared with other GNN and its other variants on the basis of prediction error.

5. Theoretical Analysis of Islanding Phenomenon in Distributed Generation

Karthick S and Shanti Swarup K

Distributed generation faces several issues when integrated to power grid in large scale. Unintentional islanding is one such issue which needs to be addressed. Several methods already exist in literature to detect islanding instant like positive feedback method, passive method and communication based methods. This paper provides an overview of islanding phenomenon, theoretical explanation on islanding and the dynamics of the typical distributed generation system in islanded mode.

6. Life Line Characteristics of Solid Insulation under Electrical Stress

Aditya Bafna, Nirmal Shankar, Ashish Jain, Pravin Kothari and Madhu Palati

Insulating materials subjected to electrical and thermal-electrical stresses exhibit life line characteristics which show a tendency to reach an electrical threshold. Their fit is investigated with reference to several sets of data derived from accelerated life tests performed on different insulating materials.

Life line models provide the estimates of failure time percentiles at selected probabilities and stresses so that life curves at fixed failure probabilities can be drawn. These characteristics should help in the choice of compatible thermal and electrical stresses for the design of insulation systems, apparatus and components.

The tests to be conducted to plot the characteristic curves involve Class B insulation (up to 8 specimens) under three active stress levels. Subsequently, using the data acquired, the Weibull probability distribution curves are plotted using STATISTICA software.

7. Optimization of Micro grid with Demand Side Management

Jayadev V and Shanti Swarup K

In a smart grid environment, economic operation means not only to economically sched ule the generation, but also to schedule the load. In a Microgrid (MG), which comprises of intermittent DGs (eg. solar and wind energy sources), the need of Demand Side Management (DSM)/ Demand Response (DR) becomes significant. The key point in DSM is to shift the load to some other point of time, on the other hand shifting the load causes inconvenience to the customer, and hence it has to be minimized. This will become a multi-objective optimization problem to minimize the cost of generation and inconvenience caused due to the shifting of loads. In this work the authors consider an industrial/ commercial MG with one solar source, two diesel generators and one battery, with the assumption that the utility grid uses dynamic pricing. The objective function contains discontinuous function which will be difficult to solve using conventional optimization techniques and hence Genetic Algorithm based solution is proposed. The simulation results show that there is a savings with DSM compared to without DSM.

8. Optimal Hybridization of Renewable Energy Systems toImproveEnergyEfficiency

Rajashekar P Mandi and Udaykumar R Yaragatti

Energy is the prime mover of the economic growth and developmental process. To enhance the energy security of India, use of renewable energy is the utmost important. Electrical energy is the richest form of energy which is having an important role in Industrial growth. Depleting fossil fuel resources which form about more than 60 % of Indian energy generation cannot prime the growth process that is sustainable. They need to be gradually replaced by renewable sources of energy, which are perennial in nature. The increasing gap between power supply and demand is alarming the power industry to work hard in reducing the gap. In order to achieve the sustainable energy growth with the increased population and energy demand and to provide more energy to the rural populations, the non-conventional and renewable energy sources need to be installed and used [1]. The energy resource like solar radiation & wind data are measured, the energy availability, reliability of energy systems and economics of the systems are carried out by using a HOMER and MATLAB Simulink software. This paper discusses about the improving of energy efficiency by hybridization of different forms of renewable energy sources with respect to energy availability, reliability, cost, ease of operation and maintenance, etc, with detailed discussion.\

9. Integration of Renewable Energy System Solar PV with Diesel


This paper describe the sizing of solar PV, DG set and battery bank Hybrid Power System (HPS) for different configuration for share of solar &diesel power. Different configurations for integration of solar PV with diesel energy systems are explained in detail. The energy availability and economics of the integrated energy system are highlighted



10. Modeling & Analysis of Power Management by Grid Connected PV System

Grishma Patel

Now-a-days the DG system based on PV technology is becoming more popular with rang of power generation is between 1 KW to 50 KW because of its advantages like safe, clean, quiet to operate, reliable, maintenance free, flexible etc. Main objective of this paper is the Modeling of PV System components & Analysis of power management is carried out using the MATLAB/SIMULINK platform for different load & different insolation levels. In this paper it is presented that whenever load demand is less than PV capacity then remaining power is supplied to grid and whenever the load demand is more than PV capacity then load will consume the required power from the grid.

11. HERICConfigurationBasedBackToBackConverterWithReducedLosses For Regenerative Load Applications

Vani Vijay, Giridhar Kini P, Viswanatha C and Jothi Basu S

Back to back converters are used in many applications including machine drives and HVDC links. It is a combination of AC to DC and DC to AC converters with topologies suitable for the application. Here a single phase converter topology is developed by combining a Z source network and HERIC inverter which operates with lesser losses and more controllability. Compared to conventional inverter model, the conduction losses are much less in HERIC configuration. The Z source network help in boosting the DC voltage level so as to obtain the required level of AC output. This back to back converter is mainly meant for regenerative load application which can be utilized in equipment testing. The power drawn by the converter can be regenerated to supply back to the utility grid there by it is possible to conduct equipment testing without wasting energy. The details of the proposed configuration and the output waveforms are explained. Also a comparative study of the losses in conventional converter and proposed converter is presented.

12. Design and Performance Evaluation of Standalone Solar-PV System Using Interval FLC Based MPPT Controller

Neha Adhikari, Bhim Singh and Vyas A L

This paper deals with the design, modeling and performance evaluation of standalone solar-PV (Photo-Voltaic) system using interval type FLC (Fuzzy Logic Controller) based MPPT (Maximum Power Point Tracking) controller. The proposed system is designed for a 5 kW solar-PV generating system. The system consists of a solar-PV array connected with the single phase VSI (Voltage Source Inverter) through a MPPT controller and an LCL filter is used to feed the power to the consumer loads. The design procedure and modeling of the system components and controller is presented in detail. The performance of the system is evaluated in steady and dynamic system conditions to validate its design and model. The voltage controller is designed to maintain the dc link voltage and performing under varying input voltages. The output voltage and current regulator is designed to maintain the power quality under varying consumer loads and results are presented for THD (Total Harmonic Distortion) which are found under the limits of 5%.

13. Single Phase Transformerless Grid-Tied Inverter with Maximum Power PointTrackingforSolarPhotovoltaicRoof-TopSystems

Shruthi K J, Rajashekar P Mandi, Pradeep K, Viswanatha C and Giridhar Kini P

The key requirements for the control of the solar photovoltaic (SPV) energy conversion systems are to achieve very fast yet quite accurate tracking of the maximum power point under rapidly changing environmental conditions and to obtain efficient unperturbed tracking operation under steady environmental conditions. In this work, a high-performance Maximum Power Point Tracking (MPPT) technique, based on one cycle control (OCC), is proposed to meet these challenging requirements. This paper proposes single phase z-source inverter with maximum power point tracking using OCC for solar photovoltaic power generation. OCC is based on output current adjustment according to the voltage of photovoltaic array so as to extract the maximum power from it. A 1 kW grid-tied roof-top system is designed using the OCC method for MPP. Analysis & simulation using MATLAB tool, is carried out to validate the proposed technique.

14. Operation of Charge Controllers in Distributed Multi Source (SolarandWind)HybridPowerGeneratingSystems

Sudhakar H S, Gujjala B Balaraju, Pradeep K and Siddhartha Bhatt M

In large PV hybrid power systems, battery management is critical due to the continuous operation of the power system, the limited power available for temperature control in the battery room, and the high cost of maintenance.Charge controllers are required in solar or wind power generating systems where electrical energy storage is required in these systems. Optimal charging is required in order to improve the performance and life of the batteries. The charge controllers are used for optimal charging of the entire system. The different types of charge controllers, terminologies, set points and importance of hybrid system are explained in this paper. The shunt and series type charge controller’s current and voltage regulations are shown and battery current and voltage characteristics according to the source availability and load applied are also shown for the understanding.The studies of a system of the three sources (Solar, wind and diesel generator) includes than it in practice to optimize performance by 35% by optimal charging of battery using charge controller.

15. HeatTransferAnalysisofa7.5WLEDLoadwithPassiveandActivecooling for Constant Luminance Applications

Sangmesh, Gopalakrishna K and Venkatesh K

The aim of the present work is to study the thermal performance of a 7.5 W LED load with passive and active cooling and validation of the results using FEA analysis. In order to get a high cooling effect for 7.5W LED load, thermo electric cooling uses the peltier effect to create heat flux between the junctions of two different types of materials. A peltier cooler, which transfer heat from one side of the device to the other with the consumption of electrical energy, depends on the direction of the current. A peltier device (Active heat transfer device) is provided with the LED module for removal of heat generated in the module. The assembly (LED +heat sink +fan +peltier cooler) was tested for varying input power. With the use of the assembly, the junction temperatures were considerably reduced. The results indicate that, the assembly(case 4) performed better than any other cooling combinations. The validation of experimental data was done through FEA analysis.The differences between FEA results and the experimental values were 24%.



16. Evaluation of Iron Aluminide-Fly Ash Nanocomposite Prepared by Attritor Milling and Equal Channel Angular Extrusion Consolidation

Malur Srinivasan, and Dipak Chavda

An experimental investigation was conducted to evaluate the crystallite size and microhardness of mixtures iron aluminide (Fe3Al) powder and Class C fly ash in different volume percentages, subjected to attritor milling and consolidation using Equal Channel Angular Extrusion (ECAE) process. Design if experiments was employed to select the lowest size of fly ash to be mixed with pre-milled iron aluminide powder. The results indicate that crystallite sizes n the low nano-range are obtained in all iron aluminide-fly ash compacts, qualifying the compact as a nanocomposite. The microhardness of the nanocomposite is lower than that of the nano-iron aluminide indicating the possibility of porosity being developed in fly ash during processing.

17. Cement-Carbon Nanotube Composites and Their Multifunctional Behavior: A Brief Overview

Malur Srinivasan

The author has tried to provide a brief overview of the constituents of cement-carbon nanotube composites, their interactions and some examples of research on functional behavior of the composites. Many interactions are at the nanoscale and the functional behavior is strongly affected by such factors as the type and features of carbon nanotube, the proportion carbon nanotube in cement, the method adopted for dispersion of carbon nanotube in cement-water mixture, admixtures and others. Though MWCNT’ (Multiwalled carbon nanotube) is by far the more widely used, little information is available other than the diameter and length of the MWCNT, pointing out towards the need for optimization of the MWCNT features. There is thus a huge potential for optimization of structure-property relationships in the constituents of the cement-carbon nanotube composites and interested researchers are encouraged to study the full publications cited in this paper and the references cited in each publication.

The structure and properties of carbon nanotubes are first reviewed, to indicate why this material is so unique. Next, nanoscale structure development in cement is reviewed, with the hope that further research on nanoscale interactions between carbon nanotube and cement will lead to more improvements in the functional behavior of the composite. Finally, papers dealing with chosen functional properties relevant to cement-carbon nanotube composites composite, are reviewed.

18. TheWear&FrictionCharacteristicsofGlass-EpoxyCompositesforCoal Handling Parts in Thermal Power Plants

Bharathi V, Ramachandra M, Srinivasa S, Sampathkumaran P, Vynatheya S and Seetharamu S

The comparative performance of plain Glass-Epoxy (G-E) system with graphite(2.5wt.%) as filler has been reported for slide wear and friction behavior using pin-on-disc setup under varying loads and sliding velocities. This material is intended for use in coal handling systems. Besides slide wear and coefficient of friction (μ) measurements, examination of worn surface features by scanning electron microscope has been carried out to support the slide wear data. The slide wear data reveal that with increase in sliding speed, wear loss of both G-E composite and G-E plain system increase. Further it is seen that the G-E graphite filled system shows the least wear loss compared to plain G-E system. This trend is observed for all the three loads employed in this work. It is observed that the graphite bearing and plain G-E samples display a rise in the value of μ, when both load and sliding velocity are increased. The coefficient of friction of graphite G-E shows the least compared to plain G-E system irrespective of the load and the sliding velocity employed.


Vol. 10, No. 1, March 2014

ABSTRACT LIST


1. Switching and Power Frequency Transients in EHV Systems A Review and Case study

Meera K S and Santosh Kumar Patro

Overvoltages caused by transients are important in a power system as they cause stresses on electrical equipment. Majority of power system failures are directly or indirectly related to transient problems rather than steady state operation. The insulation level of each element in a power system is governed by the transient voltages originating as a result of lightning, short circuits and switching actions. In contrast to lightning, switching overvoltages originates on the system and is inherently measured in terms of the system voltage.

With the adoption of 400 kV voltages and above, it was clear that switching surges created in the system would determine the cost and strength of the major insulations to ground. This paper gives an insight to the electromagnetic transient phenomenon - switching and power frequency overvoltages and case study results of simulation for these overvoltages for a typical Indian 765 kV system.

2. A Novel Dynamic Power Controller Based VSC-HVDC Line for Power Evacuation from Independent Power Producer

Geetha R S, Ravishankar Deekshit and Ghamandi Lal

This paper presents the analysis of a Voltage Source Converter based HVDC (VSC-HVDC) system applied for evacuation of power from a medium size Independent Power Producer (IPP) with a contractual requirement that a minimum quantum of the installed capacity is to be transmitted to the permission granting agency’s grid substation. The balance power could be sold by the IPP to any other customer through open access power transmission. In the system considered, at sending end, AC power is supplied from the IPP to a DC line and also to an AC line. The DC line transmits pre-defined amount of power (equal to 60% of net power available after auxiliary consumption) to the agency’s grid substation and the AC line facilitates transmission under open access. The AC line is connected to the central grid’s substation. At the receiving end, the agency’s grid substation is interconnected to the central grid substation through another AC line. For such a transmission system requirement, a high degree of control is necessary and VSC-HVDC technology emerges as a suitable option. In this paper, a detailed simulation of power flow controllability using a novel active power controller under different generation levels of IPP is carried out and the results are presented.

Vol. 10, No. 1, March 2014

3. Node Ordering Scheme of Large Scale Power Systems Using Sparse Matrix Techniques

Prabhu S, Chandrasekar S and Kaliappan P

Power flow is the basic tool for power system analysis which reveals the system operation in a steady-state mode for evaluation of the power system planning and operations. The accuracy, simulation time, computer storage size and convergence of any model used depend largely on the size of the bus admittance matrix of the system under study. This paper, therefore, presents the study of the bus admittance matrix of the different systems with sparse techniques. And also analyze the number of zeros and non-zeros element in the different systems with minimum ordering schemes. The proposed method is validated using a 5-bus, 30-bus, 118-bus and 300-bus systems. The results are presented in graphical form and discussed. The sparse Matrix techniques show that as the system is increasing in size, the percentage of stored bus admittance elements decreases and changing the order of the nodes gives more impact on the size of the system. Thus, an appreciable reduction in the computer memory required to store the bus admittance matrix and in turn reduces the overall simulation time.

4. Dynamic Stability Enhancement of Power System Using Fuzzy Power System Stabilizer Under Different Loading Conditions

Chandrashekhar P K, Srivani S G, Shyam Sundar Sand Rashmi

The power system is dynamic in nature and is constantly being subjected to disturbances. It enters into dynamic instability when there is an imbalance between generation and varying load demand which calls for use of Power System Stabilizer (PSS). PSS is a device which provides additional signal to the voltage regulator derived from speed deviation, excitation deviation and accelerating power for damping critical oscillations. The PSS used should be capable to produce appropriate stabilizing signals against a wide range of operating conditions and disturbances. For this purpose, a PSS based on fuzzy logic control under multi-operating conditions is proposed in this paper. The performance of Fuzzy Logic based PSS(FLPSS) applied to Single Machine Infinite Bus (SMIB) system is studied for three different operating conditions; nominal load, heavy load and fault condition in transmission line. For Fuzzy PSS, speed deviation and acceleration are taken as input. The system is simulated in SIMULINK platform and its dynamic response is analyzed for system without PSS and with PSS. The results are compared for system with Conventional PSS and Fuzzy Logic PSS.

5. Challenges in Preparation of Detailed Project Report for High Voltage Distribution System (HVDS) Scheme – A Case Study

Devender Rao K, Venugopal M and Deshpande R A

High Voltage Distribution System (HVDS) is being implemented in many utilities across our Nation. In rural areas, loads particularly agricultural consumers are widely dispersed and low tension lines of 433 V run for long distances to feed a small load. Two or three low tension spans are to be laid to fetch a load of one pump set and such 30 to 40 pump sets are connected on each distribution transformer of 63 kVA or 100 kVA. These transformers are generally overloaded due to long LT lines and more number of consumers connected. This paper describes about the various aspects in preparing HVDS scheme on an overloaded 100 kVA transformer and its Cost Benefit Analysis (CBA).

6. Real Time Simulation of Multi-Area Power System with Polar Fuzzy Controller

Chaturvedi D K, Manmohan, Rahul Umrao and Vikas Pratap Singh

The Fuzzy Logic Controller has proven its worthiness for nonlinear complex systems. Multi-area power system is quite complex and nonlinear in nature. In this paper, Fuzzy logic controller (FLC) is developed for three area nonlinear power system. But there are inherent drawbacks of FLC such as its performance depends on number of rules, long computation time, large memory requirement etc. To overcome these problems, a polar fuzzy controller (PFC) is proposed to control the load frequency deviations in multi area power system. The PFC works on the basis that an angle acts as an input and controller response as an output. In conventional PI controller and FLC, two gains are to be tuned;whereas the PFC needs only one gain to be tuned, because the angle of PFC is calculated from the ratio of frequency deviation and the integral of frequency deviation. Hence, only one gain is sufficient to tune it. In PFC, only two rules are sufficient in the rule base. The work is extended to test the performance of proposed PFC in real time environment with the help of OPAL-RT simulator (OP 5142 v 10.2.4).

7. Wide Area Monitoring, Protection and Control: Requirements and Applications in Power System Protection

Dijin Divakaran and Amit Jain

Due to the large scale network complexities, system wide disturbances in power systems are a challenging issue for the power industry. When a major power system disturbance occurs, protection and control actions are required to stop the degradation of the system and restore to a normal state thereby minimizing the impact of the disturbance. Improvements in planning and operation of the grid could be achieved by Wide Area Monitoring, Protection and Control (WAMPAC) Applications. The purpose of wide area monitoring system is to monitor, assess, enable and automatically take necessary action to mitigate the harmful effects due to disturbances or faults in the system. This paper discusses in details WAMPAC. The present work also gives an overview of the Phasor Measurement technology and it benefits, requirements and applications for WAMPAC strategies.

8. DLMS Data Connectivity Architecture for Energy Meters

Mohammed Farooque Khan, Amit Jain and Paventhan A

DLMS is a platform that provides communication between meter and data collection devices. The companion specification provides secure and efficient transfer of electricity data. Many of data exchange approaches have been proposed to develop an open standard. In this paper, a client /server model of the DLMS / COSEM architecture with HDLC as the data-link layer and parameter identification of energy meters has been discussed with some of the issues also discussed in Indian context.

Vol. 10, No. 1, March 2014

Vol. 10, No. 1, March 2014

9. Reducing Auxiliary Power of Induced Draft Fans in Coal Fired Thermal Power Plants by Energy Audit


This paper describes the various opportunities for reducing the auxiliary power of induced draft fans in coal fired thermal power plants. The auxiliary power used by induced draft fans forms about 0.9 to 1.18 % of the total gross energy generation for 210 MW to 800 MW power plants. ID fans are the second largest (in rating) motor in a thermal power plant after Boiler Feed Pump (BFP). The detailed energy audit of auxiliary equipment in various thermal power stations, operational optimization and appropriate control system had shown ample scope for improving the energy efficiency of induced draft fans. The implementation of energy conservation measures reduce the average auxiliary power used by ID fans for 210 MW plant from average value of 1.18 % to 0.90 % of gross energy generation and the energy conservation schemes are economically attractive with a payback period of 1 to 5 years.

10. DeliverablesofRe-configurationinAutonomousMicro-grids

Venkata Kirthiga M and Arul Daniel S

Distribution Systems with optimally sized Distributed Generators(DGs) placed at optimal locations would become Micro-grids. These micro-grids operate either in non-autonomous mode (in conjunction with the utility grid) or in autonomous mode (in the absence of the utility grid) depending on the penetration level and sustainability of the DGs connected. This paper has suggested an optimal structure for autonomously operated micro-grids by re-configuring the radial system into a weakly meshed system. The deliverables of the proposed reconfiguration strategy in autonomous micro-grids are discussed in detail in this paper. The proposed reconfiguration strategy is found to ensure continuous power supply to the select customers of the micro-grid by enhancing a stable operation of the generators to avoid formation of accidental islands on line outages and minimizing the distribution losses. MATLAB code has been developed for the proposed methodology of reconfiguration and the standard 33 bus distribution system has been used to validate the proposed algorithm.

11. Impact of Demand Response on Unit Commitment in Microgrid Environment

Manisha Govardhan and Ranjit Roy

Demand response program (DRP) aims to reshape an inconsistent load demand and motivates the customers to reduce their energy consumption to get financial benefit. In this paper demand response based unit commitment (DRUC) model is used to study the impact of DRP on generation scheduling and total cost of the system. DRUC model describes the customer behavior for different incentive values and variation in the price elasticity matrix. The simulation study is carried out with a low voltage microgrid system with and without integration of solar and wind renewable sources (RS). It is found from the results that with the increase in incentive value and price elasticity matrix elements, customers tend to participate more in DRP which increases customer benefits and reduces total utility cost. It is also observed that integration of RS significantly reduces the total cost of the system.

12. ASimplifiedMethodologyforDeterminingOptimalLocationandCapacity of Solar PV Distributed Generation to Reduce Losses

Amit Jain and Venkata Srinath N

This paper presents distribution load flow analysis for balanced radial system in conjunction with Solar Photo-Voltaic (PV) distributed generation. The proposed approach utilizes Kirchhoff’s Current Law (KCL) and Kirchhoff’s Voltage Law (KVL) carried-out on forward and backward sweep iterative algorithm for the calculation of node voltages and currents flowing in radial branches. The power generated from solar PV system is determined by developing a mathematical model of solar PV modules that adopts to the Indian meteorological conditions. The distribution load flow analysis carried out by taking into the effect of this Solar PV generation. Optimal location for the distributed generation is determined by considering total system losses that can occur in 24 hours and the capacity to be installed is based on desired voltage improvement. The proposed approach has been implemented on standard 69bus radial distribution network. The simulation results obtained with and without inclusion of Solar PV generation are compared and discussed.

13. HighEfficientSoftSwitchingCukConverterwithRippleCorrelation Control MPPT for PV Applications

Mutta Krishna Murthy, Sandeep N and Kulkarni P S

This paper presents the application of “ripple correlation control (RCC)” maximum power point tracking (MPPT) algorithm for photovoltaic (PV) system employing dc-dc Cuk converter to maximize the output power of PV module. Soft switching commutation of the main and auxiliary switches at zero-voltage using active clamp technique allows the operation of the Cuk converter at very high switching frequencies with reduced size of reactive elements and electromagnetic interference. The combination of auxiliary switch, clamp capacitor and resonant inductor is used to exploit the advantage of high efficiency with zero switching losses. RCC technique uses the high frequency signal ripple, which makes it to converge asymptotically to the maximum power point independent of module configuration and parameters. The operating modes of converter for different switching time intervals are analyzed and design considerations are presented. The simulated performance of the converter with RCC MPPT over conventional MPPT algorithms is presented. The MPPT methods are compared on the basis of the time taken to track the maximum power point (MPP), steady state oscillations about MPP and dependence on array parameters. To evaluate the viability of ZVS Cuk converter with RCC MPPT, the entire system is simulated using MATLAB/SIMULINK platform for an 87 Wp solar PV system.

Vol. 10, No. 1, March 2014

Vol. 10, No. 1, March 2014

14. Power Quality Monitoring and Control Using Virtual Instrumentation System

Arunshankar V K and Senthil Kumar N

This paper presents and develops a LabVIEW based mathematical model for power quality analysis and enhancement. The different types of power quality problems such as voltage sag, voltage swell, power frequency distortions, and harmonic distortions can be identified and controlled suitably. Besides standard undisturbed three-phase voltage signal waveforms, six different categories of the PQ disturbances characteristic for real-time power distribution networks can be simulated on the basis of developed virtual instruments: voltage swells, sags, interruptions, high-order voltage harmonics, swells with harmonics and sags with harmonics. Each of simulated PQ disturbances can be predefined and easily changed according to user requirements, using various combinations of the control settings implemented on the virtual instrument front panel. All computations are carried out using LabVIEW 9.0.

15. Design and Analysis of Perturb and Observe MPPT Techniques for Inverter in Photovoltaic System

Shruthi K J , Giridhar Kini P , Viswanatha C and Rajashekar P Mandi

Renewable energies are the most sought after alternatives for electric energy generation. The improvement in semiconductor and power electronics technology has led to precise operation of system at maximum power point, thus increasing the efficiency of the PV system. Many maximum power point tracking (MPPT) algorithms have been developed in recent times which provide maximum power tracking under varying conditions. Among the existing algorithms, perturb and observe (P & O) is the most explored technique. In this paper a comparison between the conventional P & O and improved P & O method is brought about. A MATLAB simulink based simulation study of PV module/ array is carried out and both the MPPT algorithms are explored for z-source inverter in photovoltaic system.

16. Performance Loss in Solar Photovoltaic Array due to Non-ideal Natural Conditions

Sudhakar H S, Gujjala B Balaraju, Pradeep K and Siddhartha Bhatt M

Performance of a SPV system is dependent on temperature, array configuration, solar insolation, and shading across it. Shading can occur when the PV arrays/modules get covered by shadows of passing clouds, buildings, etc., or even by shadows cast by other modules/arrays. As a result the ideal operation of the PV systems is severely affected the P-V and I-V characteristics. The modeling of nonlinear current-voltage characteristics of solar cells for performance prediction becomes difficult under the influence of shading. Non-uniform solar radiation due to shadows casted by the other panels/modules, buildings, clouds, etc. can cause maximum power to change drastically. Partial shading of PV installations has an impact on its power production. For the simulated results it has been observed that 74.66% loss in I-V characteristics and 85.41% loss in P-V characteristics respectively. The power losses in the individual shaded cells would result in local heating and create thermal stress on the entire module/array resulting in hot-spot formation.

17. Studies and Analysis of Effects of Shading on the Performance of a Solar-Photovoltaic System

Neha Adhikari and Vikas Pratap Singh

This paper presents the studies on the solar photovoltaic system in the partial shading conditions. The standalone solar photovoltaic system for residential application of 2 kW power rating is considered in the system analysis. The proposed system is using a set of batteries for energy storage with a flyback dc-dc converter and a single phase voltage source inverter is designed with the controller to regulate the power quality at the consumer end. The studies are carried out as case studies on the different conditions of the shading and results are presented to analyze the PV output power and evaluate the overall system performance. Based on the results obtained few measures are suggested to keep the check on the performance in such conditions.

18. Input and Output Distortions in the Operation of Stand alone Solar PV Inverters and Method for Compensation


Inverter and power conditioning circuit is the most important part of solar PV system which is responsible for providing the AC output as per the requirement of the application. The presence of AC harmonics and DC ripples in the inverter is still an unavoidable drawback, even though it has reduced to a great extent in past two decades. This paper presents a detailed study of distortions in the AC and DC sides of commercial standalone single phase Solar PV inverter and the effect of the same in the application. The harmonic content is evaluated by loading the inverter using electronic loading. The reduction in distortions in the AC and DC sides by utilization of a high impedance network on the DC side of the inverter is also evaluated by simulation. A comparative study of harmonics and DC ripples in the inverter under test and the simulated impedance source inverter is also presented.

19. Modelling and Analysis of 3-Phase Inverter for Grid Connected Solar PV system with Harmonic Compensation

Lakshmanan S A, Amit Jain, Rajpourhit B S

Renewable Energy Sources (RES) are getting a great attention due to ever increasing power demand, environmental issues, and thrust toward sustainable development. The power produced from the RES like solar, wind etc. is used by the stand alone system or the feed into the electric grid. In this paper a 3-phase Voltage Source Inverter (VSI) is modeled and analyzed for grid connected Solar Photovoltaic (SPV) system. Mathematical model of three phase VSI and LC filter circuits are derived using state space analysis and Sinusoidal Pulse Width Modulation (SPWM) technique is proposed for 3-phase VSI. Harmonic elimination is done in VSI using by Pulse Width Modulation (PWM) technique by solving the non-linear equations that are used to determine switching angles of an inverter. The switching angle plays an important role to produce desired output by eliminating selected harmonics. The VSI is simulated using MATLAB/Simulink platform and harmonic elimination is done by considering bipolar switching case of the inverter. Various simulation results are presented to demonstrate the operation of the inverter. The harmonic spectrum analysis is carried out and discussed for the proposed harmonic elimination method.

Vol. 10, No. 1, March 2014

Vol. 10, No. 1, March 2014

20. Solar Photovoltaic Power Generation Forecasting Models and Techniques

Vikas Pratap Singh, Vivek Vijay, Chaturvedi D K and Neha Adhikari

The various forms of solar energy - solar heat, solar photovoltaic, solar thermal electricity, and solar fuels offer a clean, climate-friendly, very abundant and in-exhaustive energy resource to mankind. Solar power is the conversion of sun light into electricity, directly using photovoltaic (PV). The forecasting of energy Demands have become concerns for facility managers, and predicting energy generation plays a critical role in power-system management, scheduling, and dispatch operations. A reliable energy supply forecast helps to prevent unexpected loads and provides vital information for decisions made on energy generation and purchase. However, study of energy generation prediction by the photovoltaic (PV) system has been limited over the years, especially concerning short-term predictions. This study will helps in providing the details on different type of models and techniques of solar power forecasting.

21. Wind Energy Conversion System for Rural Application

Arjun M, Uma Rao K and Deshpande R A

This paper presents the use of induction generator with suitable control strategy for use as stand-alone wind energy conversion system. This may find application in remote rural areas where extension of 11 kV feeder may not be feasible due to physical terrain and where drawing of line may not be economically viable if loads are dispersed over wide area. This Induction machine is driven from a prim em over which is usually a wind turbine. The stator terminals of the induction machine is connected to a voltage source converter. The voltage source converter (VSC) is a three level diode clamped VSC. The terminals of the converter are connected to a capacitor and a battery. The battery is initially charged to 12 V and provides initial magnetisation for the Induction Generator. The terminals of the stator are also connected to an induction motor represented by RL load. Control strategy has been developed to keep the DC voltage constant irrespective of variation of load and rotor speeds. The total harmonic distortion in the line voltage of the induction machine is ensured to be within limits by employing three level converter. The proposed system is mathematically modelled using SIMULINK/MATLAB. The simulated results validate the theory studied.

22. Assessment of the Potential of Three Attritor-milled and Consolidated Nanostructured Materials for Sliding Wear-resistant Applications

Malur N Srinivasan

This paper deals with the assessment of the potential of nanocrystalline tungsten carbide-cobalt (WC-Co), titanium disilicide (TiSi2) and titanium silicide (Ti5Si3) for sliding wear-resistant applications. All the materials were milled in a laboratory attritor and the milled powders were consolidated using equal channel angular extrusion (ECAE) process in three cases and chemical consolidation using polycarbosilane (allylhydridopolycarbosilane-AHPCS) in one case. The microhardness of each consolidated sample was measured using a Vickers hardness tester. The crystallite sizes of WC-Co, Ti5Si3 and TiSi2 consolidates after ECAE and Ti5Si3 after attritor milling and prior to chemical consolidation were determined using X-ray diffraction and, the relationship between the crystallite size and microhardness in these cases was examined. The data on microhardness of all the samples was analyzed with reference to current literature to assess the potential of each consolidate for sliding wear-resistant applications. The results indicate that attritor-milled Ti5 Si3 consolidated using polycarbosilane as the binder appears to have the best potential for sliding wear-resistant applications. The experimental data reported in this paper was obtained by former graduate students under the direction of the author at Lamar University.

23. Design Optimization of Single Axis Thrust Magnetic Bearing Actuator

Dash S K and Shanti Swarup K

Design optimization of Active Magnetic Bearing (AMB) is important from the point of view of reliable and high speed operation. They are widely used in fly wheels, wind generators, high temperature applications, etc. Design and development of large air gap AMB is a challenge, This paper presents the modeling and design optimization of a large air gap AMB using open loop position stiffness. In this work, a goal seeking optimization methodology is employed for double acting AMB system where a combination of higher (CRGO electrical steel) and lower saturating magnetic material (Mu metal) is used. Adaptive Response Surface Method (ARSM) was used as a tool for optimization. A less variant position stiffness across 1500 microns air gap was arrived at after getting optimized design variables constituting geometry and excitation current parameters using above comprehensive optimization method. This investigation opens up a new way to attain position stiffness in AMB system which is less sensitive to positional variation of rotor in air gap.

Vol. 10, No. 1, March 2014

Vol. 10, No. 2, June 2014

ABSTRACT LIST


1. Comparison of PSO and RCGA for Optimal Location of STATCOM for Improvement of Transient Stability of Power Systems

Arunjothi R and Veena H S

In electrical power systems, reactive power compensation plays an important role in transient stability. Shunt flexible AC transmission system (FACTS) devices are being used in controlling the reactive power flow to the power network and, hence, the system voltage fluctuations and stability. Static synchronous compensator (STATCOM) is one of the shunt connected FACTS devices. The primary purpose of STATCOM is to support bus voltage by injecting (or absorbing) reactive power, but it is also capable of improving the power system stability. In this paper, an interconnected two-area test system with actual transmission line model is used to show the effectiveness of Particle Swarm Optimisation (PSO) and Real Coded Genetic Algorithms (RCGA) algorithms for determining the optimal location for power system stability improvement.

2. Impact of FACTS Controllers on the Dynamic Stability of Power Systems

Senthil Kumar N

The availability of flexible A.C. transmission system (FACTs) devices such as Static Var compensators (SVCs) and Static Compensators (STATCOMs), has led their use to control reactive power flows in transmission lines and system bus voltage. In addition to voltage control these devices can also be used effectively for improving the small signal stability of the power system and improve system damping. The objective of this paper is to explore the impact of the shunt connected FACTS devices namely Static Var Compensator (SVC) and Static Compensator (STATCOM), on the small signal stability of a single machine infinite bus system. A single machine infinite bus system is chosen to analyze the damping capabilities in a detailed manner.

3. Evaluation of Inter Regional Power Flows in Planning Studies

Shyam Sundar S and Chandrashekhar P K

Power System Transmission Planning involves huge investment in the Power Sector. The network condition, the available load and generation are the factors to be considered for proposing the power transfer between regions. However if the envisaged power flow could not be achieved due to constraints after commissioning of the Transmission Lines or Sub-Transmission Lines it could lead to huge financial loss to the Utilities. Hence a case study of 14 bus known network with different contingencies is brought out in this paper to visualize the limitations in inter regional power transfer in spite of available generation to be exchanged within the regions.

Vol. 10, No. 2, June 2014

4. Mitigation of Subsynchronous Resonance in Power System through STATCOM and Auxiliary Controller

Vipin Jain and Narendra Kumar

In FACTS devices, auxiliary signals are widely used to enhance damping and mitigate Subsynchronous Resonance in Power System. Subsynchronous Resonance occurs due to series capacitor in Power System. In this paper a novel auxiliary controller of STATCOM is designed with auxiliary signal ωg i.e. accelerating frequency of generator rotor mode. Auxiliary controller is superimposed on conventional PI controller. The study system is IEEE First Benchmark Model. Alone PI is not able to damp all the modes of First Benchmark Model.

5. High Impendance Fault Detection in Distribution System under Distributed Generation

Manohar Singh

Conventional power distribution systems are radial in nature, characterized by a single source feeding a network of downstream feeders. Location of faults in such power networks is very challenging when fault resistance is quite high. In distribution systems, fault location algorithms primarily utilize the fault current amplitude for deciding the nature and location of the faults. However, the distribution systems become radial nature when distributed generation sources are connected with them. Under such circumstance mere magnitude of fault current is not sufficient to locate and classify the fault on the power feeders. Additional fault informations are required for identification of faults in the interconnected power distribution systems.

This presented paper suggests a novel algorithm, which can detect the high impendence fault based on transient behavior of fault currents. The proposed algorithm utilizes the transient energy content of the high impendence fault signals for detecting the faults in the distribution networks. The PSCAD/EMTDC software is used for simulation for the faults in the power network under study.

6. AnEfficientFaultDetectionAlgorithmforMicro-Grid

Majarikar Vikrant Jiwanrao and Shanti Swarup K

This paper proposes an implementation procedure and performance testing of an algorithm comprise of Cumulative sum algorithm and power flow methods for fault detection in micro-grid systems. The Cumulative sum algorithm is found to be better than the traditional methods in the presence of noise, system frequency deviation, and other uncertainties for radial system. By monitoring the power Flows between buses along with cumulative sum algorithm, detection of faults in micro-grid system is carried out. The proposed digital Fault detection is implemented experimentally for performance testing on a test micro-grid system. Several transient disturbances viz. grid connection, single-phase to ground fault, 2phase fault, 3phase to ground faults, etc. occurring in different parts of the test micro-grid system are investigated experimentally.

Vol. 10, No. 2, June 2014

7. Characterization of Marx Generator

Madhu Palati

This paper discusses the characterization of 200 kV, 20 J mini Marx generator. Marx generators are extensively used in very high voltage fast pulse generation. Capacitors are the major components of Marx generator, apart from the capacitance of the capacitor the other parameters such as internal inductance (Equivalent series Inductance) and Equivalent series resistance (ESR) has significant effect on the output current waveform. The internal inductance of the capacitor, ESR and the discharge path to the load circuit has to be kept as minimum as possible so as to achieve lower characteristic impedance, higher peak current, faster rise time and reduced Full Width Half Maximum(FWHM). Therefore there is a need to determine the internal inductance and ESR of Marx generator. Short circuit discharge test is conducted on the Marx generator to determine the value of total inductance of Marx generator during erection. From the determined value of total inductance of Marx generator LT and erected capacitance of the Marx CT, ESR is estimated from the PSPICE circuit. Also maximum output of Marx is estimated using the PSPICE circuit.

8. SignificanceofAirCooledSystemOveraGasCooledSystemin Large Rotating Electrical Machines

Abhay Kumar Khairwar, Venkateswarlu G, Mondal N R and Raghavaiah B V

Short circuit generators are used to deliver the short circuit power in testing laboratories. During operation at the time of field excitation a large amount of heat is generated. The dissipation of this heat has to be evacuated to improve the generator efficiency and its reliability. The generator cooling goals are to minimize drag or Windage loss, keep generator internals clean, minimize electrical, mechanical and corrosion problems, and maximize generator output.

The purpose of the cooling is to dissipate generator thermal losses by forced circulation of coolant, may be gas, water or air in a closed circuit through the different parts of the generator. This paper explains the methodologies adopted to cool down the electrical machines like generators and to provide the safe working atmosphere to the personnel’s working around it and also emphasizes on challenges to handle the gas cooling system compared to the normal air cooling system. In this paper the actual cooling system is also addressed, used in 1500 MVA Short Circuit Generator.

Vol. 10, No. 2, June 2014

9. Development of Intelligent System for Induction Motor Fault Diagnosis in Ceiling Fan

Chaturvedi D K, Devendra Singh and Vikas Pratap Singh

A variety of fan faults occur in our day to day life such as electrical faults(winding faults), mechanical faults (broken rotor bars, eccentricity, bearing faults) etc. To detect the fault, many motor variables may be taken such as current, voltage, speed, sound, temperature and vibrations, so that the preventive action may be taken before the occurrence of faults in the fan. Current signature is useful for finding electrical faults such as stator faults etc. and acoustic signature is useful for finding mechanical faults such as rotor faults etc. In this paper, the on line current, voltage, rpm and temperature reading of faulty fan and healthy fan are recorded. These recorded signals are used to train a neural network so that it is able to detect the fault.

10. Space-vector Based Equal Switching Strategy for Three-level Open-end Winding Induction Motor Drive

Srinivasan Pradabane, Narasimharaju B L, Srikanth N V and Deshpande R A

This paper proposes a new space-vector based pulse width modulation strategy for a three-level open-end winding induction motor drive. The proposed method incorporates both the clamping and switching duties of the inverters within every 60o span of the rotation of the reference space vector.The proposed scheme neither requires sector identification nor lookup tables for the generation of the gating pulses. The switching pattern adopted in the present work ensures equal clamping duty and switching duty for both the inverters which are electrically isolated from each other to suppress the zero sequence currents. The switching strategy ensures the usage of all the clamping states thus making the drive system possible for maximum utilization of the switching resources. The proposed strategy is simulated using MATLAB/Simulink and experimentally validated using dSPACE.

11. Effect of Radial and Axial Movement of Winding on Coherence Function in a 220/132 kV, 100 MVA, Auto Transformer

Shashidhar Reddy K, Vishal Kulkarni, Suryakalavathi M and Singh B P

The short circuit force generated in Powers Transformers due to system fault is known to cause movement of the windings. Several diagnostic methods have been employed to identify the movement of internal components of transformer e.g. Core, winding, coil bulging, coil twisting, Inter turn fault etc. The methods include – Sweep Frequency Response Analysis, Current reflection time, wavelet transform and Coherence Function (CF). The present work reports a detailed analysis of Coherence Function due to radial and axial movement of coil by theoretically simulating the HV winding of 220/132 kV, 100 MVA autotransformer. The results show a variation in magnitude of CF for dominant frequencies and that even a small change in radial or axial distances cause significant change in magnitude of CF. It is observed that sensitivity of detection of winding movement by CF for minor faults is moderately better than Frequency Response, since CF is related to the amount of linearity between input and output. It is observed that CF and FRA are complimentary to each other.

12. Performance Evaluation of Optical Fiber Ground Wire Cable During Short Circuit Condition

Chandra Sekhar M, Santhosh J, Nanda Kumar V S, Sudhakar Reddy and Rajaramamohan Rao Chennu

Optical ground wires (OPGW) are increasingly being used on overhead transmission lines throughout the world. OPGW conductors protect the power line against lightning or short-circuit and provide communication through optical fibers embedded inside the conductor. In case of conventional ground wire, the permissible instantaneous temperature is limited by the highest allowable loss of tensile strength of metallic materials caused by annealing and bird-caging. Since OPGW conductors are expected to give protection to the embedded optical fiber, they shall meet a further requirement; i.e. the temperature of the conductor shall not rise in such extent that it may cause degradation in the parameters of the optical fiber. The highest temperature that the conductor may reach during and after short-circuit depends on the conductor design. This paper describes the testing requirements and the performance evaluation of typical OPGW conductor during short circuit condition as per IEEE Standard 1138.

13. Thermal Performance of Low Voltage Power Distribution Board Panel (PDBP) at Elevated Temperature

Viswanatha C, Vittal G P and Mohanbabu V

Thermal performance has been the subject of studies for LV equipment since decades and continues to be the established practice to assess its continued usage of the equipment in service or installation in the case of newly designed equipment. The PDBP being core of the distribution network to deliver reliable quality power is investigated for its performance in ambient temperature and at elevated temperature. Although, the equipment behavior is known at ambient temperature, its performance at elevated temperature of 55˚C is seldom studied. Recently, the temperature in the globe is on the raise leading to global warming and in addition there is requirement in industrial applications and high temperate zones. The feasibility of electrical equipment in this elevated temperature condition is not known. In this context, the equipment has been subjected to laboratory studies. The data obtained showed the interesting results such as need of thermally endured materials in the configured system of the equipment. The operation of the equipment in elevated temperature will accelerate deterioration and reduction in the service life of the equipment. However, proper thermally endured components, thermal design of the equipment will ensure for the application of the equipment in the elevated temperature. The method of Temperature monitoring of the equipment by subjecting to service condition of operating temperature and current can be applied as a means to study the thermal performance of equipment. These aspects of the experimental method, the results obtained at ambient and elevated temperature are discussed and investigated in this research work.

Vol. 10, No. 2, June 2014

Vol. 10, No. 2, June 2014

14. Review of Silicone Rubber Nanocomposites for Outdoor Insulation

Ganga S, Moumita Naskar and Prasenjit Biswas

Polymer nanocomposites have attracted wide interests in high voltage insulation due to their excellent electrical, thermal and mechanical properties. Among the new insulating materials extensively used as high-voltage outdoor insulation, silicone rubber (SIR) has received the most attention. Indeed, SIRs are gaining popularity as an effective counter-measure to handle the high voltage insulation problems. In recent times nano sized fillers (Nano fillers) have sought great deal of research scholars’ attention and has brought revolution in the polymer industry due to its better interaction with polymer. A relatively less quantity of nanofillers in comparison to micro filler is reported to achieve the required properties in SIR. In this review, the effectiveness of the most common nanofillers of SIR for dielectric applications along with various dispersion methods is presented. But numerous experimental investigations on nanocomposites have indicated a significant decrease in electrical, thermal, mechanical and surface properties, due to the agglomeration of nanofillers. Agglomeration can be reduced by using modified nanofillers & optimum quantity of nanofillers, high shear mixing, or by efficient filler dispersion methods but it is almost impossible to entirely eliminate this effect with the presently available technologies.

15. Vibration Damping in Overhead Transmission Line Conductors

Praful R Dongre, Ramesh Babu R, Ananthbabu M D and Revanna D

Fatigue is a common cause for failure of conductors near associated hardwares and attachment. Vibrations due to wind is a common cause for fatigue and frettingof conductors. Conductors under the effect of high frequency and low amplitude are more prone to vibrations particularly in India and other parts of the world. ACSR conductors have been a popular choice for overhead conductors due to advantages in both electrical and mechanical characteristics and these conductors are more prone to Aeolian vibrations. Vibration dampers are widely used to control Aeolian vibration of the conductors and earthwires including optical ground wires. In this paper the author presents the performance of vibration dampers on ACSR conductors. The author emphasizes the importance offor evaluating the suitability of a damper for a particular overhead line by choosing appropriate design tension, type, quantity and placement of vibration dampers to avoid failure of lines.

16. ImprovementofEnergyEfficiencyofBoilerFeedPumpsinThermalPower Plants through Intelligent Prediction and Operational Optimization


This paper describes the various methods for enhancing the energy efficiency of Boiler Feed Pumps (BFP) in thermal power plants. The specific auxiliary power used by BFPs vary between 2.2 to 3.6 % of the total gross energy generation for units ranging from 30 MW to 800 MW units. The average specific power used by BFPs for 210 MW plants is 2.4 to 3.2 % of gross energy generation. The energy efficiency improvement of BFPs by reducing the re-circulation flow, pressure drop across feed water circuit elements, enhancing overall efficiency of BFPs, etc., are discussed with case studies. The implementation of energy conservation measures reduce the average auxiliary power used by BFPs for 210 MW plant from average value of 3.6 to 2.3 % of gross energy generation and release an additional power of about 10.9 MU/year for one 210 MW unit.

17. SystemEfficiency(non-module)Considerations in the Sizing Solar Photovoltaic Plants

Siddhartha Bhatt M

This paper presents a review of the energy efficiency in solar photovoltaic (SPV) systems with special reference to quantification and improvement of non-module system efficiency. The system efficiency (also called as performance ratio) is composed of photopic efficiency (losses in light energy before actually interacting with the SPV cell surface) and electrical efficiency (losses in electrical energy output generated by the module and before it is used by the load). Non module system efficiencies of operating SPV plants range between 54.93 % to 70.16 % with an average value of 62.32 % and standard deviation of 4.57 %. System efficiency considerations are important in design of power plants for given end user loads. If the calculations are on the basis of kWpeak, a typical 100 kWpeak system gives a peak output of 50-65 kW at the load point due to system efficiency and also lowering of module efficiency due to non-standard operating conditions. System efficiency excludes auxiliary power (2-4 % of the generated power), losses in battery (~20 %) due to storage component loss of energy generated due to non-availability of the grid (for grid tied systems) and stochastic incident radiation loss (~16 %). System efficiency presents possibilities of improvement to 75-80 % level through improved system design and improved operation and maintenance practices.

18. Modeling of Grid-connected Solar Photovoltaic Energy Generation System

Neha Adhikari and Pardeep K

This paper coversthe design and modelling of a grid-connected solar photovoltaic energy generation system. Solar-PV system with MPPT (maximum power point tracking) controller to track maximum power point is designed with a dc-dc converter. The output of PV array is fed to the VSI converter through a dc-dc converter. For regulating the output voltage and current under varying conditions,a VSI is designed with closed loop controllers. Simulation model for this designed system is developed in Simulink/Matlab platform and simulated results are presented to demonstrate its performance under steady and dynamic conditions.

19. Simulation and Performance Study of Grid-connected Wind and Photovoltaic Hybrid Energy System

Nagendra K, Vinatha U and Krishnamurthy N

Hybrid energy system (HES) includes several (two or more) energy sources with appropriate energy conversion technologies connected together to feed power to local load/grid. HES allows a wide variety of primary energy sources, frequently generated from renewable sources as the stand alone system for rural electrification and also for grid extension. The objective of this work is to model photovoltaic (PV) & wind grid connected HES using Matlab/Simulink. The model is useful for simulation of PV & wind grid connected HES. Blocks like wind model, PV model, energy conversion system and loads are implemented and the results of simulation model are also presented.

Vol. 10, No. 2, June 2014

Vol. 10, No. 2, June 2014

20. Solar Power forecasting: The State-Of-The-Art

Vikas Pratap Singh and Kumar Vaibhav

In 21st century Renewable energy sources, especially Solar Energy, are to play a larger role in Hybrid Generation. There exist a number of technological, environmental and political challenges linked to supplementing existing electricity generation capacities with solar energy. Solar power forecasting can avoid many of the balancing issues, if accurate forecasts of solar output are available. Anybody trading in solar energy can negotiate a better price, if they have precise information about the volume they have to sell at any particular time.

21. Analysis of DC Link Capacitor Performance and Capacitor Life In Back to Back Converters With Respect to Converter Switching

Vani Vijay, Giridhar Kini P, Viswanatha C and Jothibasu S

Back to Back converters are commonly used converters in many ac to ac conversion applications. Even though Converters without intermediate energy storage element are developed, Those with DC link capacitors still continue to be most popular due to the inherent advantages. The performance of such converters is affected by the operation of DC link capacitors used. This paper gives a detailed study of various types of back to back converters and considerations in DC link capacitor design and selection. A MATLAB program is also developed to analyze the effect of RMS (Root mean Square) ripple current and consequent effect on the life of the DC link capacitors in Voltage link back to back converters.

22. Optimization of Solar Photovoltaic Converters for Maximum Energy Efficiency

Sudhakar H S, Gujjala B Balaraju and Pradeep K

Performance of a SPV system is dependent on temperature, array configuration, solar insolation, shading across it etc. The conversion of solar energy using SPV modules comes with its own problems that arise from the change in insulation conditions. These changes in insulation conditions severely affect the efficiency and output power of the SPV modules. For improving the efficiency of conversion of solar energy can be done by tracking the maximum power point of a PV module. There are so many types of MPPT charge controllers for doing this important work in SPV system. A dc-dc converter is essential in SPV system as it acts as an interface between the load and the SPV module. Three different basic types of converters are explained in this paper without any non-idealities. There are other types of dc-dc converters as well, but these converters from these three basic converters. Further by using these dc-dc converters the performance of the MPPT algorithms can be done for improving the overall efficiency of the SPV system.

23. A Study on the Physical and Morphological Characteristics of Aluminum Cenosphere Composite Sintered at High Temperature in Microwave

Ananda Kumar M G, Seetharamu S and Jagannath Nayak

Aluminium Metal matrix Composites (AMC) have been fabricated through powder metallurgy route comprising of Aluminum as matrix and reinforced with Cenosphere, a low density material in the form of hollow and porous spheres. The densification of the composite has been carried out in an advanced processing technique called the microwave sintering,which is rapid and economical. AMC with Cenosphere addition of 40 volume % has been prepared and sintered at various temperatures. The sintered composites have been studied for the mineralogical phases by XRD, morphology by SEM and physical properties such as Density, Apparent Porosity and Hardness (BHN). The results obtained have been compared with AMCs that were sintered conventionally. The microwave sintered samples showed better properties in terms of Porosity, Bulk Density and Brinell hardness values compared to the conventionally sintered ones.

24. Lithium Ceramics for High Temperature CO2 Capture: A Review

Lakshminarayana Bhatta K G, Seetharamu S and Sharon Olivera

Carbon dioxide capture and storage (CCS) technology is considered as promising option in the portfolio of mitigation actions for stabilization of atmospheric greenhouse gas concentration as fossil fuels continue to be the major source of energy in foreseeable future. Among the various options for CO2 capture, the adsorption technology has been widely investigated as a means of an alternative to absorption technology that is having many formidable problems. Recently there is a growing interest in solid sorbents; those can efficiently capture CO2 in the temperature range of 200-700 °C. Applications of high temperature adsorbents are envisioned mainly in sorption enhanced reformation processes (SERP) and CO2 removal from hot flue gas/syngas. Lithium ceramics are important class of materials in this category. This paper aims at a review of lithium zirconates and lithium silicates as CO2 adsorbents. The focus is on various aspects of sorbents such as sorption capacity, mechanism of adsorption, kinetic models, factors affecting the sorbent performance and methodologies developed for performance enhancement. However, CO2 separating membranes made of lithium-based ceramics are not discussed.

Vol. 10, No. 2, June 2014


ABSTRACT LIST


1. Modelling and application of phasor measurement units for fault location

Anirudh Singh, Shikhar Dwivedi and Senthil Kumar N

Wide area monitoring and control using Phasor Measurement Units (PMU’s) will continue to remain as one of the integral components of large power systems for different important applications in power systems which includes dynamic state estimation, power oscillation monitoring, Transient Stability Assessment etc. A wide area measuring system is composed of a PMU with High Speed Communication Channels and Phasor data concentrators. This paper explores the modeling and application of a typical phasor measurement unit to monitor voltage and current swings for different types faults and disturbances in the standard four generator two area power system.

2. Out-of-step detection in emerging power systems key issues and challenges

Srinu Babu Matta and Seethalekshmi K

The electrical power systems function as a huge and highly interconnected network dispersed over a large area. A balance exist between generated and consumed power, any disturbance to this balance in the system caused due to change in load as well as faults and their clearance often results in electromechanical oscillations inturn variation in power flows, this phenomenon is referred as Power Swing. Stable power swings changes it operating point to new equilibrium point but unstable swings collapse the equilibrium causes cascaded trippings inturn black outs or brown outs. In this paper, several methods of power system Out-of –step detection are critically reviewed. Various OOS detection techniques are discussed in brief; comparision of available approaches are examined and presented. The key issues and challenges are OOS detection are highlighted. A vast collection of papers, books and journals are listed, which is useful for interested researchers, power engineers and utility companies.

3. Development of adaptive distance relay for STATCOM connected 220 kv transmission line with wavelet transform and ANN

Ramchandra P Hasabe and Anil P Vaidya

A new scheme to enhance the solution of the problems associated with Transmission line protection with Statcom connected is presented in this paper. Static Synchronous Compensator (STATCOM) is a shunt type FACTS device connected at the midpoint of the transmission line to maintain the voltage at desired level by injecting/absorbing the reactive power. This connection affects the performance of distance protection relay during line faults. The fault detection is carried out by using energy of the detail coefficients of the phase signals and artificial neutral network algorithm used for fault distance location for all the types of faults for 220 kv transmission line. For each type of fault separate neural network is prepared for finding out the fault location. An improved performance is obtained once the neutral network is trained suitably, thus performance correctly when faced with different system parameters and conditions.


4. Adaptive polar fuzzy load frequency controller for nonlinear multi-area power system

Chaturvedi D K, Rahul Umrao and Vikas Pratap Singh

Fuzzy logic controller is based on human experience. Human experience is encoded in the form of fuzzy rule base to control the system. It is difficult to decide the size of fuzzy rule base. As the number of rules increases the performance of controller is better. At the same time its complexity increases which in turn affects the computation time and memory requirements. To overcome these problems, a Polar Fuzzy logic controller (PFC) is proposed for the load frequency control problem of nonlinear three area interconnected power system. In this paper, The PFC is made adaptive using Real Coded Genetic algorithm- fuzzy system (RCGAF) approach. The performance of simple PFC and adaptive PFC using RCGAF is compared with fuzzy and conventional PI controller.

5. Reliability constrained unit commitment problem incorporating demand response program

Manisha Govardhan, Fenil Master and Ranjit Roy

In a restructured power market, the independent system operator (ISO) executes the reliability constrained unit commitment (RCUC) program to plan a reliable and an economical hourly generation schedule for the day-ahead market. This work presents probabilistic method for the incorporation of the unavailability of the generating units in the solution of the Unit commitment (UC) problem. In this paper, Gbest Artificial Bee Colony (GABC) algorithm is used for solving the UC problem, while the evaluation of the required spinning reserve capacity is performed by using Loss of Load Probability (LOLP) index. IEEE RTS 24 bus system is used to demonstrate RCUC problem for different reliability levels. Considerable developments in the real time telemetry of demand-side systems allow ISO to use reserves provided by demand response programs (DRPs) in a restructured power market. In this paper, the hourly demand response is incorporated into RCUC for economic and reliability purposes. The RCUC problem with Emergency Demand Response Program (EDRP) is tested on IEEE RTS 24 bus system. Minimum cost results for each case and reduction in load demands for DRPs are formulated.

6. A Study on the evaluation of sandwich busduct using temperature rise method

Viswanatha C, Vittal G P and Mohan Babu V

Different types of busducts like Isolated Phase Busduct, Segregated and Non Segregated Busducts are used in Power Distribution Network which occupies voluminous, large space of the equipment. Recently, Sandwich Busducts have come into vogue because of their compactness, light weight, low impedance, and fire retardancy besides several other advantages. However Sandwich Busducts need to maintain high quality conductors, superior design, high dielectric withstand voltage. These properties would meet the requirements of electrical parameters but for the requirement of thermal specifications, it is Temperature rise method widely employed to monitor the thermal performance of Sandwich Busducts. In the present investigation, modular designed Sandwich Busducts are chosen and studied using Temperature rise method. The samples of Sandwich Busducts are subjected to Temperature rise method. The temperature at critical points of Sandwich Busducts are monitored and evaluated in the light of International Specifications. Of the many inferences derived, the important observations at thermal steady state for busduct, incoming and outgoing terminals have been obtained. The present paper focuses on assessing the components forming Sandwich Busduct for their evaluation to apply to field conditions in the Electrical Power System Network.

7. A review of health monitoring techniques of induction Motor

Chaturvedi D K, Md. Sharif Iqbal, Mayank Pratap Singh and Vikas Pratap Singh

Induction motor is singly excited and brushless,very simple, compact and extremely rugged in construction and most reliable and low cost motor. Although, these motors are reliable but often exposed to hostile environments during its operation which leads to early deterioration leading to the motors failure. Faults and failures of induction machines can lead to excessive downtimes and generate large losses in terms of maintenance and revenues. This paper deals with the study of identification of different type of faults and the health monitoring techniques commonly used in induction motors.



8. India’s largest short circuit generator & its salient features

Ramachandrappa V and Raghavaiah B V

Short circuit test is one of the very important tests on electrical power equipment to verify its design aspects to withstand the critical severities under the condition of actual fault. To perform these tests a high power source is required. This source can be a grid supply with a high fault level or can be a high power short circuit generator. This paper gives the salient features of high power generator installed at Central Power Research Institute (CPRI), Bangalore. This 2500MVA short circuit generator is of highest capacity in the sub-continent of South Asia as on date. The design features are intricate in nature and complex in terms of stator, rotor damper winding and stator end winding. This paper presents the specification, design concept, constructional features, comparison between salient pole and turbo type of generators and other auxiliaries of the generator. Mechanism of achieving the maximum short circuit current is broadly discussed in this paper. This rare facility at CPRI meets high power testing requirement for the electrical industry and utilities of India and other part of the world. In this paper attempts are also made to bring out the highlights of operational features of capital intensive 2500 MVA SC generator. This generator has been used for short circuit testing of various power system components over the period of time.

9. Traceability of high current measurements in short circuit laboratories

Nagaraj V, Maroti and Sudhakara Reddy S

To establish traceability for high current measurements, comparison tests of high current shunts in High Power Laboratories have been carried out with STL reference shunts since 2005. This paper describes the comparison test results of shunts in High Power Laboratory CPRI Bangalore. The test results shown are the shunts tested for the comparison tests performed and most of the differences of the scale factor with power frequency current between the reference shunt and those tested in participating laboratories were less than 0.7 %.

10. Wavelet spectrum energy feature extraction based fault detection scheme for synchronous generators

Nagireddy Ravi and Narri Yadaiah

This paper presents a wavelet transform based fault detection scheme for synchronous generators of power system equipment. The proposed method analyzes characterization of faults using a multi resolution analysis and defines a novel feature extraction, which is called wavelet spectrum energy. The multi-resolution signal analysis based on wavelet transform is utilized to decompose a given signal into approximate and detail signals of original signal. The detail signal coefficients are utilized for calculating wavelet spectrum energy. The fault detection technique utilizes the wavelet spectrum energy as feature extraction to extract information of fault signals for transient analysis. The simulation results show accurate discrimination of faults and also in characterization of internal and external faults.

11. Performance study of grid-connected wind and photovoltaic hybrid energy system under variation of generation

Nagendra K, Dr. Vinatha U, Dr. N Krishnamurthy and Raghu N

The aim of this work is to analyze typical configuration of grid connected wind and photovoltaic hybrid energy system. Nowadays hybrid energy systems (HES) are widely used because of inherent problems with solar energy. HES includes several (two or more) energy sources with appropriate energy conversion technologies connected together to feed power to local load/grid. These allowa wide variety of primary energy sources, frequently generated from renewable sources as the stand alone system for rural electrification and also for grid extension. Mainly the work presents the system response under generation variation of HES with grid interface. Application represents a useful tool in research activity and also in teaching.

12. Advances in steam turbines for solar thermal and integrated solar combined cycle power plants

Siddhartha Bhatt M

This paper presents an overview of developments in steam turbines in general with particular application to match concentrating solar thermal (CST) sources.

The design of solar steam generator which has a parabolic output profile is first presented. Technologies for maintaining steady steam inflow into the steam turbine, viz., hybridization of sources like integrated solar combined cycle (ISCC) and thermal energy storage (TES), cogeneration, trigeneration, etc., are explored.

The developments in the steam turbine consist mainly of upgraded materials to operate at higher steam inlet temperature and pressure, ungraded energy efficiency through 3-dimensional computation fluid dynamics (CFD) design, increased fatigue life to withstand large number of cyclic operations, increased dynamic response and automation in manufacture. It is concluded that while 3-d designed steam turbines for elevated temperatures fulfill most requirements of CST power systems, fatigue life improvement and better energy efficiency at part load, needs to be addressed.

13. Review of building integrated solar photovoltaic technology and its applications

Neha Adhikari

Building Integrated Photovoltaic (BIPV) systems is one of the most promising technologies and has recently being experiencing a technological growth. There is a consensus that these advancements may lead us to novel methods for domestic energy generation. Technical improvements, governmental policy supportive and financial aids are some of the contributors to this development. However, the amount of building integrated solar power generation as compared to other forms of solar electricity generation methods is still negligible. In this study, a review is presented including the amount of work done in this area and their findings. It summarizes the current state-of-art of these systems.



14. Optimal placement and sizing of PV system and fuel cell on distribution system for loss minimization

Vijay Gupta, Mukul Dixit and Ranjit Roy

In current scenario optimal placement and sizing of distributed generation (DG) on the distribution system is drawing attention of electrical power utilities for minimization of real power loss. Power loss minimization has some in built advantages i.e. power flow reduction in feeder lines, reduces stress on feeder loading therefore increases reliability of the utility, fulfilled the load demand during peak load period and reduction in consumer bill, etc. In this paper particle swarm optimization with constriction factor approach (PSOCFA) for optimal placement and sizing of DGs (such as solar and fuel cell based), heuristic approach is applied for reconfiguration of distribution system with the purpose to minimize the total real power loss subjected to equality and inequality constraints in the distribution system is presented. The results obtained after placement of Photovoltaic (PV) system, Fuel cell (FC) and combination of both are shown by using PSOCFA algorithm applied on IEEE 33–bus radial distribution system. It shows significant reduction in power loss with the improvement in voltage profile and voltage stability index (VSI).

15. Power grids for high penetration of solar photovoltaic power plants- a review

Siddhartha Bhatt M

This paper presents a review of power grids which have high component (~ 80 %) of solar photovoltaic (SPV) plants. It can be concluded that variability or infirmness of SPV is controllable to a large extent through detailed probabilistic modeling of the variation patterns. The immediate, short term and long term variation of SPV power plants has been discussed in depth. In a grid composed of a large number of 1-50 MW plants, the dispatchable power can be scheduled to as high as 80 % of the declared capacity in that time slot (since SPV varies in every time slot).

16. Star rating and check testing of refrigerators - CPRI experiences

Gujjala B Balaraju

With growing population, economic and industrial development, the need to examine alternative sources for generating electricity has become very important and the gap between Electrical power demand and supply in the country is increasing, so it is essential to have efforts to conserve the electricity by using energy efficient electrical products. There is always a possibility to save energy by proper usage of energy efficient components to minimize the wastage of energy in electrical appliances. The standards & labeling programme was launched for Air conditioners and Refrigerators by Bureau of Energy Efficiency (BEE) during May 2006 on voluntary basis to minimize these wastages. The manufacturers started displaying the star labels on the products from March 2007. The programme was made mandatory from January 2010. In order to verify the correctness of the star labels,BEE has introduced the check testing of the refrigerators and Air conditioners. The star rating evaluation involves the measurement of energy consumption & volume with gross & storage volume of the refrigerator along with pull down test as qualification requirement. The process of determining the energy rating consists of measuring the tested energy consumption of the refrigerator. From December 2013 to July 2014, 15 numbers of refrigerators were check tested as per BEE requirements by CPRI. The star rating of each of the models are calculated from the tests carried out at CPRI. Out of these 74% of the tested refrigerators meet the star rating claimed by the manufacturer.

17. Design of AC-DC converter with reduced harmonics and output ripples using active power factor correction technique


AC-DC converters are very commonly used in many power electronics applications including controllable sources and machine drives. Rectifier circuit results in harmonic distortions in AC side and requires large capacitive filter for reducing DC ripples on the output side. Use of active power factor technique can be utilized for solving this issue resulting in better performance of the converter. It basically consists of boost converter with high frequency switching following the rectifier controlled using a suitable microcontroller. This paper presents the detailed design and operation of Active power factor corrected rectifier which operates with reduced THD and improved power factor there by reducing losses in power flow and utility. Simulation of the designed converter and comparison with conventional topology is also discussed.



18. Improving performance of primary air fansin thermal power plants through energy conservation techniques

Rajashekar P Mandi, Seetharamu S and Udaykumar R Yaragatti

Primary Air Fans are the essential auxiliary equipment to provide the primary air to lift the pulverized coal from mills to carry to burners and also to provide partial air for combustion. This paper describes various techno-economical energy conservation measures for reducing the carbon emission by improving the performance of Primary Air fans in coal fired thermal power plants based on the energy conservation/audit study conducted in 28 numbers of 210 MW power plants in India. The best operating points for pressure gain, flow, pressure drop across hydrodynamic resistive elements, equipment efficiency, power input and specific energy consumption are simulated by using MATLAB and presented in this paper with case study to validate the results. Optimizing the pressure at PA fan discharge, control of excess air, pressure drop across APH and mills and maintaining the optimum primary air pressure at mills thereby to maintain appropriate coal-air pressure at burners will help in reduction of auxiliary power of PA fans. The implementation of energy conservation measures in a typical 210 MW coal fired thermal power plant reduce the overall auxiliary power of PA fans by 0.26 % of gross energy generation and also reduce the carbon emission by 4,056 t/year.

19. Study on the effects of coal-ash-slag deposition on boiler tubes inacoal-firedthermalpowerplant

Malabika Roy, Arvind Kumar and Janardhana M

Coal combustion in a thermal power plant generates plenty of ashes, which gets melted at high temperature. These melted ashes, i.e. slag, gets deposited on the external surface of the boiler tube in the furnace and stick to it. This slag greatly affect the heat transfer, which leads to reduction in the efficiency of the boiler. Also, slag deposition slowly corrodes the external surface of the tube. In this paper, a typical slag deposited tube was collected from a coal fired thermal power plant and metallographic analysis was carried out on this tube and the results were compared with an unexposed tube of same material, diameter and thickness. It is concluded from the analysis that there are no significant changes in microstructure, hardness values as well as inslag compositions.

20. Seismic response evaluation of substation equipment

Panneer Selvam R, Nampoothiri A N N and Ramesh Babu R

Electrical and telecommunication facilities are observed from the past earthquake data, as seismically weak and prone to service failure due to suddenly applied seismic loads. Among them substation equipment are the most vulnerable ones. A need for reliability of electrical equipment against vibrational hazards due to earthquakes has become prime importance. In order to meet the basic requirements regarding seismic qualification of equipment and thereby to ensure reliable power transmission, Earthquake engineering laboratory capable of performing a diverse range of seismic qualification requirements on equipment, sub-assemblies and components as per National and International standards has been established at CPRI, Bangalore. Seismic qualification of few equipment carried out are presented.

21. Computer aided Analysis and optimization of transmission line tower

Avinash M, Selvaraj M, Mohanbabu G and Prabhushankar G V

For economic reasons, our next generation overhead power transmission line towers will be built with new design concepts in order to reduce the weight of the support structures. This paper discusses the computer aided design and analysis carried out on a 220 kV Single Circuit transmission line tower built with a combination of Circular Hollow Sections and Angle sections rather than built with only Angle sections. After optimization, the comparative study is presented with respect to stresses, deflection and weight of both Circular Hollow Sections and Angle sections towers. There is a saving in steel weight up to 8% resulted when a Circular Hallow Section tower is compared with an Angle Section type. The analyses results are compared with full scale test carried out at Central Power Research Institute (CPRI) Bangalore, India are presented.



ABSTRACT LIST


1. Designing of supplementary controller for STATCOm for mitigation of sub-synchronous resonance in series compensated power system


In FACTS devices supplementary signals are widely used to enhance damping and mitigation of Subsynchronous Resonance in Power System. Subsynchronous Resonance occurs due to series capacitor in the Power Systems. High value of series capacitive reactance may destabilize low frequency mode which is more dangerous. In this paper modeling of STATCOM with IEEE first benchmark model is presented. Then a supplementary signal is developed which is capable to make the system stable for all critical values of series compensation. The eigenvalues are presented for all four critical values of series compensation.

2. mathematical modeling and simulation of an observer based state feedback controller of a STATCOm to improve the voltage stability of power system

Papia Chakraborty and Satadeepa Bhaumik

Power demand in India is increasing significantly day by day due to the growing population, dynamic economic growth and modernization. To meet such large and growing power needs our power system is facing power quality problems inform of low power factor, poor voltage profile, voltage fluctuations, voltage sag/swell etc. So it is indeed very essential to improve the power transfer capability of existing networks. Installation of FACTS device in existing transmission network is an alternative way to strengthen power transmission capability. A static synchronous compensator (STATCOM) is one of the FACTS devices which is used to control the reactive power and it has also the ability to regulate the grid voltage. Different control techniques are in use to control the amount of reactive power to be injected or supplied by the STATCOM. In this paper, an OBSERVER based state feedback controller is proposed for STATCOM to improve the voltage stability. Mathematical modeling for the controller is also illustrated here. Simulation of observer based state feedback control of STATCOM is performed in MATLAB/SIMULINK. The simulation result depicts the satisfactory performance of STATCOM with proposed controller during three phases to ground fault condition.


3. Comparative analysis of accelerating power input and speed input robust power system stabilizers

Javeed Kittur, Saikumar H V and Sharath Raj S V

The power system stability improvement by a robust Power System Stabilizer (PSS) using accelerating power and speed as inputs is investigated independently in this paper. The objective of the work presented in this paper is to design an accelerating power input robust PSS and a speed input robust PSS to damp low frequency oscillations arising out of small and large disturbances. The robustness of the PSS is ensured by placing all the eigen values within a specified contour in the s-plane. A nonlinear constrained optimization technique has been applied for tuning the PSS parameters with the objective of damping oscillations over a wide range of operating conditions to make the PSS robust. The design of PSS is validated by performing nonlinear simulations for small and large disturbances.

4. Decision tree approach to dynamic security assessment

Nikhil Valluru and Shanti Swarup K

Dynamic Security Assessment (DSA) of power systems is an important study for real time application in control centers. Historically, various numerical, methods have been adopted for carrying out DSA. These are time consuming and computationally intensive. So faster and easily computable methods for Security Assessment are the need of the hour. With the advances in technology, several new methods which are more effective than the earlier adopted methods have been developed. One of them is the use of Decision Trees (DTs) for Dynamic Security Assessment. The real time system data can be obtained which helps in identifying current system operating condition and hence used it in predicting whether the system is dynamically secure or not.As a result, making accurate predictions for the power system operating conditions is an important task for the current power system research. The research mainly interests in checking if the operating conditions are acceptable after contingencies.

5. Reliability analysis of protection system using neighbouring line dependability failures

Nagarajupalle Naveen and Sankar V

In power system studies, the reliability of protection systems has a considerable effect on the reliability of supply, and hence appropriate reliability models must be incorporated. A majority of studies conducted assuming perfectly reliable protection systems, and hence do not take into account the effects of failure scenarios in their operation.Modelling of the failure modes in protection systems associated with their dependability and security features is essential for comprehensive evaluation of power system reliability. There are relatively fewer works in the literature on power system reliability accounting for the impact of protection system. In this paper, common mode failure operations such as dependability failures of protection of neighbouring lines in a Power System network is considered. In an existing method, only first order and second order failures of transmission lines are considered, whereas, failure modes using higher order Cutsets are not considered. Expressions for reliability analysis are developed and software has been developed using MATLAB. The results for sample systems are obtained and analysed. From the results, it can be concluded that although probability of failure indices are increased as compared to an existing method, the proposed method is more general, realistic and approximate analysis can be carried out for any system having higher order dependable failures.

6. Customers interruption cost estimation based on reliability in power distribution system

Chandhra Shekar P, Deshpande R A and Sankar V

Reliability assessment of distribution network is an important subject due to increasing demand for more reliable service with less interruption frequency and duration. An effective way to solving this issue is by the use of quantitative assessment of reliability, measure the reliability indices to find out the probability of availability and unavailability of supply. This paper describes the energy not supplied to the customers in terms of customer kWh loss and revenue loss to the customers and the revenue loss to the utility in profit making areas is presented for two practical networks by calculating the reliability indices. The software module CYMDIST Reliability Assessment Module (RAM) is used for the simulation and analysis.

7. Improvement in the reliability performance of power distribution systems

Chandhra Shekar P, Deshpande R A, Sankar V and Manohar P

Reliability assessment is of primary importance in designing and planning distribution systems that operate in an economical manner with minimal interruption of customer loads. Distributed Generation (DG) is expected to play an increasing role in emerging power systems because they use different type of resources and technologies to serve energy to power systems. DG is expected to improve the system reliability as its backup generation. Since DG units are subject to failures like all other generation units, the random behavior of these units must be taken into account in the analysis. Existence of DG units in a distribution system will effect on restoration time of load points. The algorithm for restoration time assessment of load point is developed when DG unit is installed. In this paper, the reliability performance of distribution system is analyzed in terms of SAIFI, SAIDI, CAIDI, ASAI, ASUI, ENS and AENS. The algorithm to calculate the reliability indices for simple 9-bus radial distribution feeder with and without DG is developed. The improvement in the reliability of the feeder is studied for different locations of DG with respect to fault point. All the above analysis is carried out by developing MATLAB software.

8. Effect of static var compensator on the performance of digital distance relay protection of transmission line

Mohan P Thakre and Vijay S Kale

This paper presents modelling of distance relay with static Var compensator (SVC) and investigates its impact on the apparent impedance seen by the transmission line distance relay. The functional structure for SVC built with a Thyristor Controlled Reactor (TCR) and its model are described. The model is based on representation of the controller as variable susceptance (BSVC) that changes with the firing angle of the TCR. SVC has a remarkable effect on the apparent impedance seen by the distance relay.The impact of SVC is more pronounced on the apparent impedance seen by the phase to ground fault. The mal-operation of the distance protection for the transmission line with SVC at various locations is studied. It is also shown that the primary winding connection of the interfacing transformer of the SVC has extraordinary effect on the apparent impedance seen by the relay. The simulation results show that the under-reaching and over-reaching is more severe with SVC at mid-point of the transmission line. The impact of SVC on the relay tripping boundaries is also clearly demonstrated.



9. Gas tightness test methods for gas insulated mV and HV switchgear

Govinda Rao G, Santhosh J and Raghavaiah B V

This paper elucidates the methods used in type testing and factory routine testing to ensure the tightness of SF6 gas used in Medium Voltage (MV) and High Voltage (HV) switchgear as per the latest IEC and CIGRE guidelines. Gas insulated MV (>1 kV to ≤52 kV) and HV (>52 kV) switchgear are frequently being used in electrical power system throughout the world. Mostly, gas insulated MV and HV switchgear contains SF6 as a pure gas or combined with other gases (i.e.: N2) to form a gas mixture.Recent times, distinct emphasis is being paid to reducing gas leakage during design, manufacturing and operation by enhancing gas handling procedures in compliance with Greenhouse gases emission regulations. Typically the assurance of gas tightness of MV and HV Switchgear shall be defined as the lowest possible quantity of SF6 released to the atmosphere. Various test methods are used for tightness test measurement depends upon sensitivity of measurement, quantity and necessity.

10. Ampacity of bundled PVC house wiring cables in a conduit pipe based on experimental and theoretical considerations

Meena K P, Arunjothi R, Thirumurthy, Raja G K and Nageshwar Rao B

Flexible PVC Cables form the major part of Power distribution system within residential buildings, industrial buildings, and other commercial institutions. The ampacity of power cable depends upon the cross sectional area of conductor and the laying and installation of the cable in service. Generally two or more number of PVC cables are bundled together and inserted as a bundle in a conduit pipe for connecting to various load points. As the bundling of cables produce more heat than a single PVC Cable, and dissipation of heat is poor, the ampacity of these cables reduces considerably. Hence the exact selection of sizes and no. of cables are essential to avoid overheating of those cables and the resulting fire havocs.

PVC House wiring cables consists of copper conductor extruded with PVC insulation and are installed generally through a conduit pipe in a bundled manner. The steady state current rating of these cables depends on the way the heat generated in the cable due to current and the heat transmitted to the cable surface & then dissipated to the surroundings. The maximum conductor temperature is limited by the type of insulating material used. In this paper theoretical and experimental results of steady state ampacity ratings of bundles of house wiring PVC Cables laid in conduit pipes are compared.

11. Capacitor switching phenomenon for EHV circuit breaker

Santosh Gundap, Manik Hapse, Vishal Vaidya, Snehal Khetre

While, shunt capacitor bank are extensively used to improve loading of the transmission lines as well as to support system voltages. As these capacitor banks are frequently switched in and out of duty, enegisation and de-energisation of these bank causes transient voltages are produced. The concerns on energisation are overvoltage and inrush current, while for de-energisation is restriking.

Switching of capacitor bank, Capacitor bank because of their concentrated capacitance, in contrast with distributed capacitance, generally draws much more current than unloaded cable or line- in practical cases up to several hundred of ampere. Switching of Capacitor bank causes a very high rate of rise of transient recovery voltage across circuit breaker contacts. With improvements in circuit breaker technology, modern SF6 circuit breakers have been designed with less number of interrupter per pole. This causes, modern circuit breaker operates with higher voltage stress in the dielectric recovery region after current interruption. Catastrophic failures of circuit Breaker during shunt reactor and capacitor bank de-energisation. In those cases, evidence of cumulative re-strikes has been found to be the main cause of interrupter failure.

12. Seismicqualificationofelectricalcabinet

Panneer Selvam R and Ramesh Babu R

Electrical cabinets are widely used in power control systems. Electrical cabinet is housing for many delicate protection, measuring and control equipments like relays, meters, circuit breakers, logic device, printed circuit board etc. Seismic load should be one of criteria for selection of electrical enclosures. Seismically qualified Electrical cabinet ensures proper functioning and safety of equipment installed in it during and after seismic event. Electrical enclosures should not amplify seismic waves and should withstand seismic load without undergoing any physical failure. A typical Seismic qualification test carried out on an electrical enclosure is discussed in this paper.

13. Switched reluctance drive in industrial application

Yogesh Pahariya, Rakesh Saxena, Bhim Singh

This paper presents the developed switched reluctance motor drive for various applications. The various applications related to motoring and generating operations are described. The block diagram schemes of applications are discussed for various control strategy, basic requirements, sensing techniques and torque speed characteristics. The survey of applications with various manufacturing industries is given. The performance of controller and control strategies for various applications are compared. The Switched Reluctance Motor Drive has compared with conventional motors related to various applications and its suitability.



14. Estimation of induction motor parameters: an overview

Chaturvedi D K, Mayank Pratap Singh, Md. Sharif Iqbal and Vikas Pratap Singh

The parameters of induction motor depends on various factors such as: machine internal state, machine ageing, magnetic saturation, operating conditions, the coupling effect between the internal system and external system. The paper deals with an overview of parameter estimation of three phase induction motor using different soft computing techniques. The soft computing techniques which are considered in the paper are fuzzy system, artificial neural network (ANN), Neuro-Fuzzy, genetic algorithms (GA) and particle swarm optimization (PSO). It is observed that the estimated parameter using soft computing techniques were much closer to actual value.

15. ConceptofAPFCwithreferencetotheenergyefficiency

Vishal Singhal

Increasingly, Indian Industry is paying one of the highest power tariffs in the world. Countries in this club such as Germany and Italy have benefited from Automatic Power Factor control as a competitive edge. They are already global leaders in Automatic Power Factor Compensation (APFC) Capacitors and Panels. This paper is aimed at APFC users and takes a hands-on look at extending the lifetime payback of APFC equipment. The effects of Current, Voltage, Harmonics and Temperature and their interplay are discussed. These produce degradations in Capacitors and Contactors. Subtle problems go unnoticed since the equipment is operating silently in a corner, until a catastrophic breakdown occurs. This paper also discusses practical guidelines for panel designers and users. Peak Inrush Current limiting, forced cooling, Component specifications, component selection and the role of the APFC controller with its protective functions are examined.

16. Effect of ambient temperature on the performance of power electronic converters

Vani Vijay, Giridhar Kini P, Viswanatha C and Pradeep K

Efficiency of power electronics devices are highly dependent on temperature. Hence temperature compensation and heat sink design are very important factors in maintaining the performance quality of power electronic converters. Thus the ambient temperature at which the device is operating also effects the performance since the heat removal by heat sinks or cooling fans is affected by the ambient temperature. Here a detailed analysis of the dependency of losses in power electronic switches on the junction temperature and in turn ambient temperature is presented. A theoretical Analysis of conduction losses and effect of ambient temperature on it is presented along with a set of experimental results by analyzing the performance of a 850W Solar PV inverter at various ambient temperatures. The results are satisfactorily explaining the effect of ambient temperature on converter efficiency.

17. Novel control strategy of three phase grid tied inverters for power quality improvement

Chandrasekhar B, Sanjay Lakshminarayanan, Sudhakara Reddy S

Renewable energy sources (RES) are being increasingly connected in distribution systems utilizing power electronic converters. This paper presents an advanced control strategy for achieving maximum power quality benefits from the grid interfacing inverters when installed in 3-phase distribution systems.The grid tie inverter can be utilized as i) Power converter to inject power generated from RES to the grid and ii) shunt active power filters to compensate current imbalance, load current harmonics, reactive power demand and load neutral current. All of these functions may be accomplished either individually or simultaneously. This control concept is clearly explained with MATLAB/SIMULINK simulation results and THD is less than 5%.

18. Steady State and transient performance of an inverter based microgrid

Jyothsna T R, Ramya Sree B, Ramya V and Deshpande R A

The analysis of small-signal stability of conventional power systems is well established, but for inverter based microgrids there is a need to establish how circuit and control features gave rise to particular oscillatory modes and which of these have poor damping. This paper develops the modeling and stability analysis of autonomous operation of inverter based microgrids. Each sub-module is modeled in state-space form and all are combined together on a common reference frame. The model captures the detail of the control loops of the inverter but not the switching action. Some inverter modes are found at relatively high frequency and so a full dynamic model of the network (rather than an algebraic impedance model) is used. The complete models linearized around an operating point and the resulting system matrix is used to derive the eigenvalues. The eigenvalues (termed “modes”) indicate the frequency and damping of oscillatory components in the transient response. A sensitivity analysis is also presented which helps identifying the origin of each of the modes and identifies possible feedback signals for design of controllers to improve the system stability. With experience it is possible to simplify the model (reduce the order) if particular modes are not of interest as is the case with synchronous machine models. Transient stability results have been obtained from a microgrid of three 10-kVA inverters.

19. Optimal allocation of distributed generator in a radial distribution system using genetic algorithm and particle swarm optimization

Ashwin N and Veena H S

Many areas in power systems require solving one or more nonlinear optimization problems. Optimal allocation of distributed generators (DGs) is one of them. This paper proposes two optimization methods to determine the optimal allocation of distributed generators in radial distribution systems (RDS), for the purpose of maximizing power loss reduction and improving voltage profile. The proposed methodology uses Genetic Algorithm (GA) and Particle Swarm Optimization (PSO) to optimize the objective function and is used to compare it with the analytical method of optimization. The Genetic Algorithm and Particle Swarm Optimization methods are tested on a standard radial distribution test systems, which is, IEEE 33 bus RDS using MATLAB R2008b. The results indicate that the optimal location of the DG is at bus number 6, with a power loss reduction of 83.3 kW.



20. Design of hybrid power plants for Indian conditions

Siddhartha Bhatt M

This paper presents the basic considerations for design of solar photovoltaic-wind-battery-grid connect hybrid power plants(HPPs). For ensuring the successful operation of hybrid power plants at low diesel input and low battery storage requirement, high level of reliability of power supply and reliability of component are essential. This paper provides factors involved in ensuring that high level of reliability of components and power availability is fulfilled in the hybrid plants. For both SPV and wind, the annual energy generation is divided into three regimes: summer, winter and rainy seasons and all these three have to fulfil the load requirement. It is seen that for 30% solar and 70 % wind generation curve is the smoothened with less variation.With improved day ahead predictability of both wind and solar the reliability can be improved considerably.

21. Strength analysis of designed dual axis sun tracker using solid-work software

Neeraj Tiwari, Sanjeev Kumar and Vikas Pratap Singh

This paper describes an approach to the design and implementation of sun tracker stand in PV system making 120 Volt string. For the strength analysis against wind pressure the PV system with tracker stand has been implemented in solid work software version SP-13. Another part of this paper is the comparison of power drawn from The PV system with tracker and without a tracker. The data received in real experimental setup. We analyzed that the efficiency of PV systems can be increased by 42 % compared to the static PV system by implementing the tracker techniques in the PV System.

22. methods of optimal charging of lead-acid battery for improving its performance and life span

Sudhakar H S, M S Indira, Gujjala B Balaraju and Siddhartha Bhatt M

Battery is an electrochemical energy storage device that converts chemical energy into electricity, by use of a galvanic cell. The paper presents operation of lead acid battery, its chemical reactions and the charging methods to improve its performance and life span. The constant current charging mode results in overcharging of the battery as it is being pushed at full current. The constant voltage charging mode takes more time to charge the battery fully due to float charge, but the battery will not overcharge improving the life span. If the lead acid battery is undergoing deep discharge repeatedly then the life span of the battery will be less than its rated value. The operating temperature also has bearing on the life span. The paper is also presents the introduction to battery management system (BMS,) which is the heart of the battery system. The BMS involves a sophisticated supervisory control and data acquisition system (SCADA) with data management, control, protection and prediction.

23. Dynamic model of heat ventilation and air conditioning (HVAC) system

Srinivas M and Swarup K S

This paper describes the implementation of SCADA to the HVAC (Heat Ventilation and Air conditioning) system, which is one among physical systems present in the spent fuel storage facility. The spent fuel storage facility contains the large number of equipment and control devices to maintain the facility critical parameters in the permissible limits. The mathematical model of HVAC system is done to monitor the critical parameters like temperature and humidity with respect to zone conditions. Over time both the radioactivity and the cooling requirements decrease and these parameters are to be monitored and controlled. The work projects deals the implementation of SCADA system to the spent fuel storage facility and monitoring of the critical parameters, the alarms to be generated for the abnormality situation. The scope of the work covers the SCADA design, modelling and monitoring of the critical parameters of the HVAC.


Vol. 11, No. 1, March 2015

ABSTRACT LIST


1. Fuzzy and PID stabilizers for power systems for small signal stability enhancement

Noopura S P, Amit Jain and Jayan M V

Small signal stability investigation is important for stability analysis of power systems as a small signal disturbance could be an initiating event for a large system outage. Fuzzy logic as a novel method for power system stability has attained wide importance in the recent years. In this paper, stability studies have been carried out for a single machine infinite bus system which has been modeled according to the Heffron Philips model. A comparison between the conventional lead-lag, PID and Fuzzy controllers for damping the system oscillations has also been carried out in this paper. The system is simulated in MATLABTM Simulink environment and the results have been presented.

2. A multi objective optimization of transmission expansion planning using genetic algorithm considering reliabilty criteria

Srinivasulu G, Subramanyam B and Surya Kalavathi M

An electric power system plays a crucial role in the economic and social development of a country. Economic growth in India has spurred the need for more power and hence the infrastructure to transport the power. Sufficient transmission capacity is very essential in any long-term planning for improving the availability and supply of power. So Transmission Expansion Planning (TEP) is integral to the development of a stable and reliable power infrastructure. TEP infuture is a very complex task which needs a coordinated and analytical analysis of various scenarios and contingencies. In this work we have implemented a scheme for TEP which factors load growth and considers N-1 contingency. Both economics and technical considerations are considered in the appraisal of the most desirable transmission network. A multi objective optimization approach is suggested and the optimization of the expansion plan is done with the help of Backward Search (BS), Forward Search (FS), Hybrid Search (HS) and Genetic Algorithm (GA). The TEP is prepared for a 6 Bus-Roy Billinton Test System (RBTS). Transmission Planning Index (TPI) is introduced to provide a clear indication to the planner about the choice of the plan. The plans suggested by different optimization algorithms are compared in terms of performance measures and reliability indices.

Vol. 11, No. 1, March 2015

3. A novel distance estimation technique for single line to ground fault in electric distribution network using smart meter

Velhal Geeta Vilas, Avani Pujara, Bakre S M and Muralidhara V

Smart grid concept promises a reliable and efficient supply of electricity. It recognizes the growing importance of Information and Communication Technologies (ICTs). Monitoring, communication and controlling are the main systems which can transform the conventional grid into the Smart Grid. A vivid study of components of the smart grid i.e. smart meter, ICT, Internet Protocol (IP) based hierarchies, Advanced Metering Infrastructure (AMI) is completed. Smart phone based communication is drawing attention now days in Smart Grid environment because of the use of Global System for Mobile Communication (GSM) technology and its real time interactivity. It is based on Client–Server communication. To initiate a point to point Client Server connection, the transmission control protocol (TCP) would be used. This paper includes a novice technique for locating single line to ground fault, and methodology to be applied for it. Fault location is calculated using the real time data obtained from 400 kV Jejuri substation. The length of the Bhigwan – Bilt Graphics line has been measured using Tauraus kit, and inferences are drawn.

4. Multi-layered feed-forward back propagation neural network approach for solving short-term thermal unit commitment

Pavan Kumar V and Kulkarni P S

This paper presents an approach for solving the short-term thermal unit commitment (UC) problem using a multi-layered Feed-forward Back propagation Neural Network (FF-BPNN). The main focus of the paper is on finding the schedule of committed thermal units within a short computational time such that the total operating cost is minimized. The proposed method is implemented and tested on a 3-unit and 10-unit systems for a scheduling period of 4-hours and 24-hours respectively in MATLAB software using the Neural Network toolbox. Comparison of simulation results of the proposed method with the results of previous published methods shows that the proposed FF-BPNN method provides better solution with less computational time.

5. Design and tuning of FACTS stabilizers for dynamic stability enhancement in multimachine power systems

Senthil Kumar N

This contribution discusses and compares different control techniques for damping undesirable electromechancial oscillations in power systems by means of power system stabilizer and Series /Shunt FACTS controllers. The linearized model of the power system is derived with FACTS controllers and the problem of small signal stability enhancement is formulated as an optimization problem to maximize the damping ratio of critical electro mechanical modes in the power system. Particle swarm optimization (PSO) technique is applied to tune the controller parameters of the PSS and FACTS controllers. The following FACTs controllers are taken for analysis (i) Static Var Compensator (SVC) (ii) Static Compensator (STATCOM) (iii) Thyristor Controlled Series Capacitor (TCSC) (iv) Unified Power Flow Controller (UPFC).

6. A brief review of super-excitation schemes in short-circuit generators

Sreeram V, Gopal D H and Ravindra Mohare M R

Most short circuit generators have static excitation systems to supply field current to the rotor circuit. All synchronous alternators suffer a reduction in the terminal voltage due to high armature reaction which is a result of the extremely high magnitude short-circuit currents. The reduction in terminal voltage will lead to a corresponding reduction in the stator current magnitude. The short-circuit generators are expected to maintain a constant magnitude of current for specified duration to complete the tests as per corresponding standards. Hence the short-circuit generators invariably make use of super-excitation to maintain the required magnitude of short-circuit currents for specified duration. During circuit breaker testing, it is required to maintain the recovery voltage at pre-fault levels. This requires significant over excitation of the machine. This paper presents a brief review of the methodology and algorithm of super-excitation schemesadopted in short circuit testing along with actual data recorded at the High Power Laboratory at CPRI, Bangalore.

7. Short time current withstand strength of earth electrodes-experiences with testing

Maheswara Rao N, Vasudevamurthy B R, Swaraj Kumar Das and Raghavaiah B V

The earth electrode is the main component of the earthing system which is in direct contact with the ground and thus provides a means of releasing or collecting any earth leakage currents. The electrode shall have good electrical conductivity and shall not corrode in a wide range of soil conditions. The design of these electrodes shall be such that they have good current carrying capacity under the earth fault conditions. This paper describes current withstand capability of these Earth Electrodes during earth fault conditions. Recent developments in Electrodes and their performance for different fault currents are given. Failure cases are studied from the laboratory tested Electrodes and appropriate recommendations were proposed. This can give an insight for estimating fault current withstand capability of a given dia and material of Electrode. Also different filler materials used for earth electrodes have been discussed.

8. Stability analysis of multi machine system using FACTS and renewable energy source

Ravi Babu G and Gowri Manohar T

In this paper, to achieve damping improvement of an offshore wind farm (OWF) fed to a multi-machine system using a static synchronous compensator (STATCOM) is presented. The operating performance of the studied OWF is simulated by an equivalent aggregated doubly-fed induction generator (DFIG) driven by an equivalent aggregated wind turbine (WT) through an equivalent gearbox. A fuzzy logic controller (FLC) plus adaptive neuro-fuzzy inference system (ANFIS) are designed to achieve adequate damping characteristics to the dominant modes of the test system under various operating conditions. A frequency-domain approach based on a linearized system model using root-loci technique and a time-domain scheme based on a nonlinear system model subject to a three-phase short-circuit fault at the connected bus are systematically performed to examine the effectiveness of the proposed control schemes. It can be concluded from the simulated results that the proposed STATCOM integrated with the FLC plus ANFIS is shown to be superior for improving the stability of the system considered.

Vol. 11, No. 1, March 2015

Vol. 11, No. 1, March 2015

9. Performance analysis of current control technique with RSVPWM and discrete model predictive control technique for 3-Phase voltage source inverters

Lakshmanan S A, Amit Jain and Rajpurohit B S

Voltage Source Inverter (VSI) is one of the essential Power Electronic Converters (PEC) which is used to utilize the power from the Renewable Energy Sources (RES) in an efficient manner. Some of the RES produces power in the form of the dc. VSI is used to convert the dc power into ac power. Various control techniques are implemented to control the inverter circuits. This paper presents a performance analysis of current control with Revised Space Vector Pulse Width Modulation (RSVPWM) technique and Discrete Model Predictive Control (DMPC) technique. This analysis is performed on 3-phase VSI. Basic concepts, control circuits, mathematical models are explained and the control techniques are simulated using MATLAB / Simulink tool. Simulation results are presented and performances of the both control techniques are compared.

10. Transient analysis of cyber-attacks on power SCADA using RTDS

Abhiram Amaraneni, Mahendra Lagineni, Rajesh Kalluri, Senthilkumar R K and Ganga Prasad G L

Cyber security in the SCADA domain has become one of the major concerns of all the stakeholders in the energy sector. The SCADA architecture that the power industry adopts is drawing more attention from a dedicated cyber attacker due to the extent of damage a catastrophe can promise. The usage of open standard protocols for communication among SCADA components that are not designed with security in mind is one of those vulnerable areas for any attacker. The SCADA components in the control region viz., the MTU and the RTU communicate via these insecurely designed open protocols without any authentication. An attacker can target this communication; launch an attack like the man-in-the-middle attack resulting in a disastrous situation. An experiment was conducted at CPRI using their Real Time Digital Simulator (RTDS) simulating a substation to study the impact of an attack. This paper brings out the details of the experiment conducted and the results thus obtained.

11. An intelligent power supply utilization system based on microcontroller for renewable energy applications

Manish Kumar Ghodki Akhilesh Swarup and Yash Pal

The proposed hardware “an intelligent power supply utilization system based on microcontroller for renewable energy applications” is a system in which microcontroller is used to automatically control the power supply of conventional energy source with the help of renewable energy source and power supply utilized in this way is then used to feed to the load. In this system, supply from the mains is altered with the help of microcontroller according to the nonlinear supply from solar energy and this altered power supply of one source is then compensated by another source. This technique will help to maintain the optional power supply to the load from renewable energy source. The control strategy for this kind of power supply utilization is written in the assembly language. The system based on this

logic can be used as one of the energy saving option and a tool for promoting and encouraging the renewable energy sources.

12. Grid integrated photovoltaic system with active and reactive power control using fuzzy based controller

Nilesh Shah and Chudamani R

Photovoltaic (PV) panels are costlier and have poor efficiency in energy conversion. Therefore, it is essential to utilize a PV based system effectively. The characteristics of PV cell are very much nonlinear that show only one point corresponding to maximum power on P-V curve when the insolation is uniform. But in partial shading situations, the P-V curve shows many peaks among which only one point corresponds to the maximum power. In this paper, grid interactive PV system is proposed with active as well as reactive power control capability even under partial shading conditions using a novel global peak power point tracking algorithm based on fuzzy logic. The proposed PV system delivers active as well as reactive power in presence of sunlight. In the absence of sunlight and under low insolation, the inverter of the PV system provides compensation of load reactive power otherwise inverter remains unutilized. This improves the utility of PV system and thus enhances the efficiency of the system. The proposed system is simulated for different partial shading and changing load conditions using MATLAB/SIMULINKTM. The simulation outcomes authenticate the performance and effectiveness of the proposed system for active and reactive power flow control with the proposed control approach.

13. Improvedefficiencystudyofsingleaxistrackingmodelcomparedtostatic photovoltaic system

Neeraj Tiwari, Sanjeev Kumar and Vikas Pratap Singh

This paper presents the performance study of single axis tracking system compared static PV system. To increase the efficiency of PV System. We designed a simple and cost effective 170W sun tracking system for the experiment. The whole experimental setup has been implemented in SimulinkTM platform for the analysis of improved efficiency. The objective of this paper to optimize the solar energy receivers. In this paper, a Simulink model of the static PV system and Tracking PV system has been presented. In the fabrication of real sun tracker system we used a 24 VDC motor and a simple LDR based control circuit for the tracking purpose. The block diagram with detailed description and performance of the tracking system are presented.

14. A study of boost converter with solar photovoltaic system for maximum energyefficiency

Sudhakar H S, Indira M S, Gujjala B Balaraju and Siddhartha Bhatt M

Performance of a SPV system is dependent on temperature, array configuration, solar insolation, shading etc. The conversion of solar energy using SPV modules,change in insolation conditions which severely affect the efficiency and output power of the modules. Improvement in the efficiency of conversion of solar energy can be done by tracking the maximum power point of a PV module. Various types of MPPT charge controllers are available in the market. A dc-dc converter is an important component of a SPV system as it acts as an interface between the load and the SPV module. These dc-dc converters enhance the performance of the MPPT algorithms leading to an improvement in the overall efficiency

Vol. 11, No. 1, March 2015

Vol. 11, No. 1, March 2015

of the SPV system. This paper presents the modeling and simulation of one diode equivalent circuit of solar photovoltaic module using MATLAB/SIMULINKTM along with the boost converter which gives an efficiency of 93.29%.15. 3-D space vector modulation algorithm for multilevel inverters in abc coordinates for solar PV applications

Aparna Paulose Vani Vijay Reeba S V and Neha Adhikari

Solar PV based Power generation is gaining importance in the present scenario of energy crisis. Precise control of Solar PV inverter is a very important factor deciding the efficiency and performance of Solar PV sources. Space Vector Modulation (SVM) technique is widely used for pulse width modulation in inverters, especially for power supplies for obtaining improved sine wave output. It is based on the representation of the three phase quantities as vectors in a two-dimensional using α and β co-ordinates. Here, a new three–dimensional (3-D) space vector algorithm in a-b-c co-ordinates for multilevel inverters is presented, which is based on the 3-Dimensional geometry of the vectors. This method calculates the on-state duration of switching vector without involving trigonometric functions, look-up tables or coordinate system transformation. Hence the computational complexity is very less compared to other algorithms. The proposed scheme is explained for a multilevel inverter and simulation results are presented with comparison of performance of a two level inverter and a three level inverter using this technique. The results shows that the algorithm can be applied for higher level inverter so that it operates at reduced Total Harmonic distortion.

16. Design of two-stage soft-switched module inverter for photovoltaic applications

Elanchezhian P, Kumar Chinnaiyan V and Sudhir Kumar R

In this paper two stage boost photovoltaic micro inverter system using maximum power point tracking is presented. First the photovoltaic module is analyzed using SIMULINK software. The main aim of the paper is the boost converter with microinverter to be used along with a Maximum Power Point Tracking control mechanism. The MPPT is responsible for extracting the maximum possible power from the photovoltaic and feed it to the load via the boost converter which is used to steps up the voltage to required magnitude. Both the boost converter, and the solar cell are modelledusing Sim Power System blocks. Here the voltage source inverter is cascaded and it injects sinusoidal current to the grid. The dynamic stiffness are obtained when load or solar insolation changing rapidly. This paper investigates in the detail concept of Maximum PowerPoint Tracking (MPPT) which significantly increases the efficiency of the solar photovoltaic system.

17. Multi input DC- DC converters for hybrid renewable energy systems-an overview

Chandrasekhar B Sanjay Lakshminarayanan and Sudhir Kumar R

Single input DC-DC converters can be successfully replaced by a single, multiple input DC-DC converter. The structure of Multiple-Input Converter (MIC) is simpler compared to the use of several single input converters for each source. Using input renewable energy sources like photovoltaic (PV)

source, wind source and fuel cell, etc, MIC can deliver power either simultaneously from all of the input sources to the load or individually. MICs reduce the system size and cost by reducing the number of components. This paper presents integrated Buck, Boost, Buck-Boost multi input DC-DC converters circuit configurations, theoretical aspects, their operational principles, merits and demerits.18. Optimal sizing of battery storage system by utilizing the reactive power

capability in wind based distribution network

Sangeetha R S, James Ranjith Kumar R, Amit Jain, Sreejaya P and Jayan M V

Day by day energy crisis and environmental issues are increasing. The most effective solution for these issues is the use of renewable energy sources (wind, solar etc.) in distribution networks (DN). However these have some disadvantages and one among them is uncertainty in nature. So it’s difficult to utilize the full potential of renewable energy sources. By using battery storage systems (BSSs) this problem can be avoided. In this paper, an optimal power flow (OPF) is formulated, for the spilled energy calculation. For maximum utilization of spilled energy BSS needs to be properly sized and here, it is done by a nonlinear programming (NLP) technique. Also, maximum potential of BSSs can be exploited by providing both active and reactive power from BSS to the network. The methodology is applied to a 47 bus Indian distribution system and results demonstrate that, there is a significant reduction in energy supplied by the grid and losses due to the integration of BSS. In this work it is assumed that wind generators are integrated into the network.

19. Wind load assessment on guyed steel tower with three different codes

Veerendra Kumar Shukla and Selvaraj M

Guyed towers are special structures widely used in communication industry as antenna supporting structures. A guyed tower is a nonlinear structural system in which the mast, consisting of single beam-column or multiple members are supported elastically at various points along its height by inclined pretension cables with their ends anchored to the ground. In this paper the wind loads on 120 m tall guyed tower are estimated with three different codes of practices, Indian Code, American Code and British Code. The estimated wind loads are compared and brought out in this paper.

20. Optimization of ambient energy component in large mixed mode central AC plants

Siddhartha Bhatt M

This paper presents the study of energy efficiency improvements of central air conditioners (AC) through the optimal integration of natural air ventilation functions. There is potential for energy saving through the shifting to mixed mode air conditioning invoking the ambient energy for cooling. An optimization study shows that up to an ambient temperature of 22 ˚C, passive cooling can be used and beyond that temperature active cooling is required. Simulation of energy consumption for air condition has been undertaken in 5 major cities of India, viz., Bengaluru, New Delhi, Mumbai, Kolkata and Chennai. The energy efficiency specified as per ECBC (energy conservation building code of India) is 80-90 kWh/m2/year for AC and can only be reduced through passive cooling components. Results indicate that it is possible to reduce the energy consumption by almost 50 % through the use of natural air ventilation cooling.

Vol. 11, No. 1, March 2015

Vol. 11, No. 1, March 2015

21. Effect of ethanol on the performance and emission characteristics of biodiesel fuelled diesel engine

Ashok Kumar K, Kapilan N and Nagaraja K V

The fossil fuel resources are depleting day –by-day and there is an increasing demand of fuels which increases environmental pollution. This problem leads to stringent emission regulations which pose a challenge to science and technology to find out environmental friendly fuels. Among the renewable energy sources, biodiesel derived from vegetable oils and fats are considered as an immediate substitute for the fossil diesel in the I.C.Engines. In India, biodiesel derived from non-edible oils such as honge, jatropha, neem, mahua, simarouba etc are considered as an alternative fuels to the fossil diesel, as there is demand for the edible oils. In this work, biodiesel was produced from non-edible honge oil by two step transesterification. The honge biodiesel properties were determined and most of the fuel properties are similar to the fossil diesel. However, Biodiesel has high viscosity, lower volatility which affects the atomization and spray formation. In this regard, the alcohol such as ethanol which is having lower flash & fire point, high flammability and is produced from renewable energy sources was used as good additive for biodiesel to improve its fuel properties. In this work, the engine tests were conducted on a single cylinder, four-stroke direct injection diesel engine using diesel, honge biodiesel and ethanol blended bio-diesel in four different compositions by volume ranging from 5% to 20% . The Engine performance and emission characteristics were analysed by varying the load. From the engine test results, it was observed that, the BE5 i.e. 5% ethanol in biodiesel results in better performance than other blends and neat biodiesel operation.

22. A case study of high temperature reheater boiler tube failure

Arvind Kumar

Several investigations on the failure of boiler tubes of thermal power plant have been carried out. This paper presents the failure analysis of a reheater tube of 210 MW thermal power plant. The reheater tube got damaged after service exposure a life of 1,65,900 hrs. The failed tube has a slit type opening with minor circumferential expansion at the rupture section. Scale was observed on the inside and outside surface of the tube. The scale formed on the outside and in-side surface of the tube was analysed through EDX and XRD to know the constituents of the scale and in evaluating the cause of failure of the tube. The tube was observed through its cross-sectional for the wall thinning. The area around the failed reheater tube sample was prepared and studied for structural degradation; hardness mapping was also carried out on the tube to find the cause of failure.

23. Fly ash cenospheres – A resourceful material for engineering applications.

Ananda Kumar M G, Shekhar Kumar M, Suryanarayana K, Vynatheya S, Venkatesh T R, Seetharamu S, Jagannath Nayak

In India, about 60% of the total power generation comes from thermal power stations operating on fossil fuels like coal and lignite [1]. Presently about 400 million tons of coal and lignite is consumed annually for power generation. Typically, Indian coals have an average ash content of about 45%, thereby leading to generation of around 180 million tons of ash annually as an industrial by product.

Out of the total ash generated, 70 % of this ash comprises of fly ash and the remaining are bottom ash, economizer ash, air-preheater ash, etc. Presently, dry fly ash is being utilized in a big way in value added products like bricks, blocks, pavers, etc., while bulk volumes of fly ash is consumed in blended cement manufacture, different types of concrete, construction of dams, roads, river embankments, etc.

Fly ash also contains about 1.0 % hollow particles called as ‘Cenospheres’ generated during combustion of the pulverized coal at high temperatures in the thermal power plant boilers. Cenospheres is a useful by-product of coal combustion which can be harvested from the ash ponds or by any other methods such as tribo-electric separation, slurry precipitation, pond skimming etc., from fly ash. Fly ash cenospheres are unique in the way that they possess excellent properties such as lightweight, low density, non-metallic, high melting points. These unique properties make cenospheres a prospective raw material to produce value added products for use in engineering applications. The paper discusses the work carried out at Central Power Research Institute on cenospheres characterization and development of value added products for various applications.

Vol. 11, No. 1, March 2015

Vol. 11, No. 2, June 2015

ABSTRACT LIST


1. Strategies for detection of out-of-step phenomenon for power system protection and control

Dijin Divakaran and Amit Jain

Power systems, nowadays, are subjected to severe oscillations during the post disturbance span of time because of its operation at very narrow stability margins. Out-of-step condition is a consequence of transient instability and protection against out-of-step condition is a major issue for the power industry. In order to operate a system safely and to protect from the damages caused to system components such as generators, transmission lines and switching equipment, proper out-of-step detection and necessary protective action has to be provided. This paper explains the various out-of-step detection strategies which can be augmented to the numerical relaying algorithms, their computational simplicity and reliability and also discusses the issues and challenges related to implementation.

2. Powersystemstability:Modeidentificationinthepowersystem oscillations using wide area measurement systems

Matta Srinu Babu, Ajay Shankar and Seethalekshmi K

In the past few decades power system oscillation damping remains as one of the major concerns for secure and reliable operation of power systems. In response to a continual increase in demand, power systems are driven closer to their limits, especially those of transmission capacity. As such, enhancing the transfer capability, while keeping the system stable, is one of the main goals for system operators. When we transfer a bulk amount of power over a long distance through relatively weak tie lines and high gain exciters then problem of small signal oscillation occurs. These oscillations have also resulted into instability and blackouts in the power system. In this instability problem there are different frequency components which are known as modes. This paper work consist of identification of low frequency components i.e. local area and inter area modes of oscillations in two area power system and also in IEEE 39 bus system.

3. Loss reduction and reliability optimization in electrical distribution systems usingnetworkreconfiguration

Ravi Kumar D and Sankar V

Network reconfigurationis an operation strategy, which alters the topological structure of the distribution feeders by rearranging the status of switches in order to obtain an optimal configuration, minimise system losses and to improve reliability. In this paper, an approach using Distribution Load Flow(DLF) solution and a reconfiguration algorithm that enhances voltage profile, reliability and voltage stability index besides minimising losses is developed. The proposed algorithm has been implemented on33 bus Radial Distribution System (RDS) in the MATLABTM environment.

Vol. 11, No. 2, June 2015

4. DC fault analysis in voltage source converter based HVDC link

Karishma S K B, Sreedevi J, Noor Cheshma P and Sarada K

The use of voltage source converter (VSC) based HVDC transmission for the interconnection of various power networks is increasing day by day. However, VSCs susceptibility to DC faults, particularly the potential damage caused to the converter switches due to overcurrent, is an issue. The fault clearing must be done very rapidly, to limit the effect of the fault on neighboring networks. This paper analyses the two terminal behavior of a VSC- based HVDC system under DC fault condition. In this work, HVDC link is connected between the systems of two different frequencies. Simulations are carried out in RSCAD/RTDSTM software and the performance of the system is analyzed for DC faults and the results are presented.

5. Multi-layered feed-forward back propagation neural network approach for solving short-term thermal unit commitment

Pavan Kumar V and Kulkarni P S

This paper presents an approach for solving the short-term thermal unit commitment (UC) problem using a multi-layered Feed-forward Back propagation Neural Network (FF-BPNN). The main focus of the paper is on finding the schedule of committed thermal units within a short computational timesuch that the total operating cost is minimized. The proposed method is implemented and tested on a 3-unit and 10-unit systems for a scheduling period of 4-hours and 24-hours respectively in MATLABTM software using the Neural Network toolbox. Comparison of simulation results of the proposed method with the results of previous published methods shows that the proposed FF-BPNN method provides better solution with less computational time.

6. Intelligent distance to over current relay coordination in sub-transmission networks

Manohar Singh, Manikya Sastry and Lalitha SVNL

Sub-transmission power networks are primarily protected by distance relays and over current relays are used as backup relay due to their poor operational speed. Coordination of distance to over current relays is achieved in this research paper by optimally selecting the over current relay parameters which constitutes relay time-inverse characteristics and relay parameters and zone-2 setting of distance relays. Solving such type of combine distance to over current relay coordination problems is tedious job using the conventional optimization methods. Therefore an evolutionally based optimization techniques is applied in this research paper which selects the optimal over current relay parameters, user defined time inverse relay characteristics and zone-2 settings of the distance relays.

7. Power loss reduction and voltage stability enhancement by optimal location of UPFC

Siva Subramanyam Reddy R and Gowri Manohar T

The power system is a very complex system. The considerable components of power system are voltage, power flows real and reactive power losses. These components are controlled by compensating the system. The system can be compensated by the various types of devices such as static capacitors, synchronous condensers etc. But the devices which are mentioned are not providing the flexible control of the power system components. The majority of the losses are shared by the transmission system. By controlling the parameters at transmission, the total system is controlled. So the devices with the combination of power electronic devices provide the flexible control on the transmission system of the power system parameters which are called FACTS devices. This paper proposed the combined series-shunt compensation FACTS device called UPFC. This paper mainly concentrated on the suitable placement of the UPFC FACTS device for Loss reduction and enhancement of voltage profile of the power system using Fast Voltage Stability Index (FVSI).

8. Optimal DSTATCOM placement in radial distribution system using fuzzy-ANFIS

Ramesh Babu U, Vijay Kumar Reddy V and Tarakalani S

Paper aim is to obtain voltage control with optimal DSTATCOM placement to decrease the total cost of voltage regulators and losses. This algorithm makes the initial selection, installations and buck-boost setting of the DSTATCOM which provides a smooth voltage profile along the network. It is also used to obtain the minimum number of the initially selected DSTACOM, by moving them in such way as to control the network voltage at the minimum possible cost. Software using MATLABTM has been developed and implemented using back track algorithm, fuzzy logic and ANFIS (Artificial Neuro Fuzzy Inference system) results are compared.

9. Cryogenic cooling aspects of HTS power cables - A review

Ipsita Das, Nageshwar Rao B, Sundara Rajan J, Seetharamu S and V V Rao

HTS (High Temperature Superconducting) cable has the ability of transmitting electrical power over long distances in an economical way, with improved stability and reliability. HTS Cable also provides a compact and low-loss transmission power line, in comparison with the conventional cable made out of copper or aluminium. The use of HTS tapes facilitates the cable operations with liquid nitrogen cooling system. A wide variety of HTS Cables with various cooling arrangements have been designed and developed. Their performance has been tested to obtain various thermo-hydaraulic and electrical data by installing the cables of different lengths in transmission and distribution networks. This paper reviews the cryogenic cooling aspects of previous and ongoing projects on superconducting cables for electrical power transmission around the world.

Vol. 11, No. 2, June 2015

Vol. 11, No. 2, June 2015

10. Design of high temperature induction motor for application in sodium cooled fast reactor control system

Nashine B K, Rajendra Prasad, Vijay Sharma and B P C Rao

Prototype Fast Breeder Reactor (PFBR) employs induction motors of various power ratings in high temperature ambient and sometimes corrosive atmosphere. Safe operation of the reactor depends on robustness and reliability of induction motors in its critical components. Safety related systems such as shutdown and online inspection systems, utilize induction motors as actuators in their mechanisms. Since external cooling is not permitted in control and inspection motors, special design of motors is required to withstand high temperatures. This paper deals with design, analysis, fabrication and testing of a compact 50 W, three phase induction motor, suitable for operating up to 250 °C ambient with winding temperature withstand capability up to 550°C. The designed motor was analyzed with two dimensional Finite Element Model (FEM) code FEMM to study the torque slip characteristics and magnetic flux density patterns in stator and rotor.

11. On line gNN based induction motor parameter estimation

Chaturvedi D K, Mayank Pratap Singh, Md. Sharif Iqbal and Vikas Pratap Singh

The induction motor is commonly used in industries due to its rugged construction and almost no maintenance. To precisely control the induction motor, accurate estimation of parameters is required. Artificial Neural Network (ANN) is used in the past for parameter estimation. The conventional ANN has its own problems such as learning issues, unknown size of ANN and its connections, etc. To overcome some of its problems generalized neural network is used in this paper. The GNN is trained to estimate parameters of three phase induction motor. Experimental setup is developed in DEI, which is consisting of a 415 V, 3Φ squirrel cage induction motor, data acquisition system and on-line parameter estimator.

12. On line cooling system fault detection in induction motor


Induction motors are popularly used as an electric drives are the critical component in industrial systems. Most of the faults in induction motor are because of excessive heat generated in the machine. In the industrial application a large rating of induction motors are used which produce a significant heat. The heat is produced in the motor due to the different losses accumulated in the machine. Hence a healthy cooling system is always required to dissipate the heat and maintain the motor temperature within acceptable limits. This paper deals with the problem occurred specially in the cooling system under different operating conditions and investigate them. The on-line information is gathered from the machine about temperature, current and vibration signatures at different operating condition and the health of the cooling system is analyzed. Soft computing techniques are utilized for this purpose.

13. On line cooling system fault detection in induction motor


Induction motors are popularly used as an electric drives are the critical component in industrial systems. Most of the faults in induction motor are because of excessive heat generated in the machine. In the industrial application a large rating of induction motors are used which produce a significant heat. The heat is produced in the motor due to the different losses accumulated in the machine. Hence a healthy cooling system is always required to dissipate the heat and maintain the motor temperature within acceptable limits. This paper deals with the problem occurred specially in the cooling system under different operating conditions and investigate them. The on-line information is gathered from the machine about temperature, current and vibration signatures at different operating condition and the health of the cooling system is analyzed. Soft computing techniques are utilized for this purpose.

14. Knockdown analysis of the performance of solar photovoltaic plants

Siddhartha Bhatt M

This paper presents an efficiency map of a solar photovoltaic (SPV) plant through knock down analysis for the three major cell types monocrystalline silicon (C-Si), multicrystalline (M-Si) and amorphous silicon (A-Si). The highest efficiency achievable by a SPV cell is the Shockley-Queisser (SQ) limit which is the ultimate efficiency. When it comes to computing the working cell efficiency which can be treated as the SQ nominal conditions (after considering the cell losses) there is a drop. Moving up the organizational level, while at the module level, there is a further drop in the overall efficiency by 2-3 % points between the cell and the module. Further drop is seen when computing under Standard test conditions (STC) conditions and (PTC conditions PV-USA industrial test conditions). The STC module efficiency is taken as the reference or base condition for the SPV plant design. From the module to the array there is yet a drop of 3-4 % points. The performance drop of the plant from the STC conditions to the actually achieved conditions can be represented by the performance ratio (PR) which considers the stochastic efficiency of the plant site. The PR excludes excludes auxiliary power (2-4 % of the generated power), losses in battery (~20 %) due to storage component (if storage is present) and loss of energy generated due to non-availability of the grid (for grid tied systems). The stochastic incident radiation loss (~16-37 %) is already accounted in the PR. Automation helps to a large extent in tracking the component efficiencies and correcting the losses.

15. Photovoltaic Emulator

Shashank V, Srinivas Reddy T and Kulkarni P S

In order to facilitate the testing of PV systems, PV panels are required and it is necessary to connect them in different configurations to get the required output voltage and power. The output of PV panels depends on environmental factors like insolation, temperature, inclination of the panel, partial shading, etc. hence it is difficult to maintain and reproduce the same characteristics of PV panel. Therefore PV emulator is required to maintain and reproduce the same characteristics irrespective of weather conditions to facilitate the testing of PV systems. The aim of this paper is to design a controlled DC-DC converter which acts as PV emulator.

Vol. 11, No. 2, June 2015

Vol. 11, No. 2, June 2015

16. Design and testing of a novel single-stage half-bridge AC-DC converter for battery charging

Nandagopal J L, Lekshmi R Chandran Remya R and Vani Vijay

AC-DC converters are used in most of the electrical utility applications especially in battery charging. Here, a novel topology for single-stage bridgeless AC-DC converter is presented which can give an isolated output voltage and input power factor correction. The input current to an AC-DC converter is rich in low order harmonics and so the total harmonic distortion is high and input power factor is poor. Hence Power Factor Correction (PFC) schemes have been implemented. The effectiveness of the converter is tested and verified in PSIMTM simulation software and in experimental hardware prototype. This topology is found to have reduced losses and better power factor correction compared to the single-stage PFC AC to DC converters with full-bridge diode rectifier. This topology is suitable for battery charging application with reduced losses and better power quality.

17. Influenceofirradiance,ambientconditionsandACpoweroutputon micro inverter temperature-overview

Elanchezhian P, Kumar Chinnaiyan V, Sudhir Kumar R and Karpagam J

Solar energy is one of the cleanest and reliable sources of renewable energy on earth. Conventionally, extraction of solar power for electricity generation was limited to PV farms, however lately distributed generation form of solar power has emerged in the form of residential and commercial Grid Tied micro-inverters. Micro inverters temperature is strongly correlated with ambient temperature and PV module temperature, and moderately correlated with irradiance and AC power. Ambient temperature is the influencing factor under conditions of low irradiance in morning hours, when the irradiance is below 60 W/m2. Noon time data analysis reveals that the micro inverters thermal behaviour is more strongly influenced by PV module temperature than AC power. In this paper review about electrical circuit topology and Influence of irradiance, AC power, ambient temperature on PV module and micro inverter are discussed.

18. An integrated double input DC- DC buck converter in hybrid energy system

Chandrasekhar B, Sanjay Lakshminarayanan and Sudhir Kumar R

Integration of more than one energy source depends on the power electronic converters is an interesting and challenging task for researchers. In this paper, integrated double input DC to DC converter for low voltage energy source applications is explained. Integrated buck converter which can step down the input voltage according to output voltage required at the load end. The converter is able to integrate different voltages of various energy sources such as solar photovoltaic, wind energy system, fuel cell and diesel etc. of relatively low voltage. The converter is designed considering double input, in which same or different type of two inputs can be used individually or simultaneously. Modes of operation of converter are described in detail, closed loop simulation with a PI controller using MATLAB/SimulinkTM results are presented in detail.

19. Studies on the performance and emission characteristics of Mahua oil fuelled low heat rejection diesel engine

Ashok Kumar K, Chethan Kumar N and Kapilan N

The world energy reserves are depleting day-by-day and the demand is increasing. This leads to search for suitable renewable alternative fuels. Among the available alternative fuels, biodiesel can be used as an immediate substitute for the diesel engine. However, the biodiesel fuelled diesel engine gives lower brake thermal efficiency due to higher viscosity and lower volatility of the biodiesel. Hence, in this work, an attempt was made to increase the performance of the biodiesel fuelled engine using ceramic coating on the engine combustion chamber components. In this experimental study, engine components such as cylinder head, piston, exhaust and inlet valves were coated with Nickel Chromium (NiCr) alloy and Yttria Stabilized zirconia (Y2O3 –ZrO2) of thickness 250 µm using plasma spray coating. Since mahua oil has significant potential for the biodiesel production, it was used for the biodiesel production. In this work, the engine tests were conducted on a single cylinder four stroke direct injection diesel engineand different blends were used as the fuels. The engine performance and emission characteristics were analysed by varying the load under both coated and uncoated conditions of the engine and results were compared with neat diesel. From the engine test results, it was observed that the engine performance with biodiesel blends such as B10 and B20, was increased from 3 to 7% depends upon the load on the engine with thermal barrier coating as compared to the normal engine without coating.

20. Damage assessment of attemperator of thermal power plant boilers

Dhiraj M Gourkhede

Due to rapid growth and development and the demand for power, has pushed steam plant design into new territories of temperature and thermal cycling. Coupled with this has been the tendency for plant suppliers to buy rather than design critical items of equipment in the hope of minimising exposure to the consequences of malfunction however, this has seen an upsurge of trouble in several areas –particularly with attemperator. Although simple in concept, attemperator can cause serious problems if details of their design are not properly considered, and/or if they are not properly applied to the systems they are to serve.

This paper presents by using optical fiber based video imaging technique to identify the affected regions in the attemperator which causes the malfunctioning of the boiler which may resulting catastrophical failure and damaging its components. This will result in reduced frequency of forced outages of the plant which in turn lead to substantial savings to the utility.

Vol. 11, No. 2, June 2015

Vol. 11, No. 3, Sept 2015

ABSTRACT LIST


1. Transient recovery voltages of circuit breakers in UHV transmission system

Meera K S, Deshpande R A and Shivakumara Aradhya R S

Circuit breakers are an important element in a substation, which is used for coupling of busbars, transformers, transmission lines, switching of shunt reactors, capacitor banks etc. The most important task of a circuit breaker is to interrupt fault currents and thereby protect various power system components. This task requires operation of the circuit breaker under different making and breaking conditions such as - faults in the vicinity of the circuit breaker, short-line faults, out-of-phase closing/opening, switching of - capacitor /shunt reactor banks, no-load transformers/lines etc. During opening operation, after the arc extinction, the insulating medium between the breaker contacts has to withstand the rapidly increasing recovery voltage. This recovery voltage has a transient component (transient recovery voltage, TRV) caused by the system when current is interrupted. The TRV of the Circuit Breaker is a decisive parameter that limits the interrupting capability of the Circuit Breaker. The TRV to be adopted for system voltages of 1200 kV, towards which our country is migrating, needs to be estimated by transient studies as they cannot be extrapolated from lower voltage systems. This paper deals with the modeling and study results of TRV for typical 1200 kV networks and a sample 1200 kV Indian system using Electromagnetic Transient Programs (EMTP).

2. Mitigation of voltage sag using D-STATCOM for a test system

Prabhakar C, Prasanna T S and Deshpande R A

During earlier days, due to conventional loads power quality did not cause any problem as there was no effect on majority of the loads connected to the electrical distribution system. But in modern power systems, power quality is certainly a major concern. With the use of sophisticated devices, the performance is very sensitive to the quality of power supply. The most common type of power quality disturbance in the present days are voltage sags and swells. Among various devices proposed for this purpose for mitigation, VSC technology was considered as it has fast responses. This paper is intended to mitigate voltage sag using Distribution Static Compensator (D-STATCOM) for a test system. The simulation is carried out for a 9 bus test system using PSCADTM/EMTDCTM to illustrate the use of D-STATCOM in mitigating the voltage sag in a distribution system.

Vol. 11, No. 3, Sept 2015

3. GABC optimization algorithm for solving simultaneous transmission expansion planning and substation expansion planning

Chandrakant Rathore

This paper presents the Gbest-guided Artificial Bee Colony (GABC) optimization technique for solving the transmission and substation expansion planning simultaneously. The motive of the proposed approach is to minimize the summation of the Transmission line Investment Cost (TIC) and the Operation Cost (OC). The OC is the combination of the fuel cost of generating units and the total wind power uncertainty cost (TWC). To reduce the power demand now-a-days more renewable energy resources are integrating in the system by the system operator. Hence, this work also adopted the wind power uncertainty factor. The DC power flow model is used to formulate the mathematical structure of Simultaneous Transmission and Substation Expansion Planning (STSEP) problem. To have more complexity on the proposed problem load uncertainties are also considered. The proposed model is tested on the modified IEEE 24-bus reliability test system. Different case studies are considered to demonstrate the effectiveness of the adopted study. Detailed analyses on the numerical results are briefly presented. The results obtained indicate that with load variations the total cost of the system has increased, as well as the selection of lines and substations have also varied.

4. Measurement and study of radiation levels and its effects on living beings near electrical substations

Raghu N, Krishna Murthy, Nagendra K and Trupti V N

The electrical substations are used to step-up or step-down the generated voltage from generating stations to receiving stations while transmission of electrical power. The substations are mainly used to step down voltage and transmit electrical power. The electromagnetic fields at these substations can be harmful to living beings. The objective of this work is to measure and study the radiation levels of a particular substation using NFA1000TM solutions device used to measure radiation levels.

5. A study of failure analysis in SF6 circuit breaker

Viswanatha C, Mohan Babu V and Rakesh K G

The circuit breaker of SF6 type has many advantages over conventional type, being better performance and dielectric properties. SF6 circuit breaker are now being employed widely in substations for better electrical network functioning. Even then, it is associated with some failures which are reported in the field. Two kinds of circuit breaker are studied in this work with point of thermal behavior. A rated current is passed through SF6 circuit breaker and thermal mapping is recorded at incoming terminal and outgoing terminal, enclosure and other points for investigations. The steady state condition of temperature is taken as reference in finding temperature rise over the environment condition. The temperature at predecided points of circuit breaker both for passed sample and failed sample are recorded. The data obtained is analyzed and attempt is made to understand the failure of SF6 breaker in the context of excessive temperature than the prescribed limits of International Specifications. This paper deals with sample arrangement, experimental details, results and analysis. Both failed sample and passed sample have shown contrast performance in final analysis.

6. Implementation of the pumped-storage unit on static transmission network expansion planning problem considering emission

Chandrakant Rathore

This paper presents the impact of the pumped-storage (PS) unit on the static transmission network expansion planning problem (STNEP). The aim of this work is to minimize the total cost and emission produced by the CO2. The total cost is the summation of the transmission line cost and the fuel cost of the generating units. In growing power industry the generation sources are the main equipment, as there are various types of the generating sources. Their selections are done to achieve a more eco-friendly and economical. Hence, the impact of emissions on the STNEP needs to be analyzed. The proposed problem is tested on the IEEE 24-bus system and the gbest-guided artificial bee colony (GABC) optimization algorithm is applied to this problem. The results obtained indicate that the PS unit is effective to reduce the total cost and CO2 emission level.

7. Modelling of three zones distance relay with auto-recloser function using PSCAD/EMTDCTM simulation: an active learning tool

Mohan P Thakre, Vijay S Kale, Raju D K, Umre B S and Junaghare A S

Protection is a very important aspect of power system. To an undergraduate and post graduate student, the learning of the course poses a major challenge, as often the course treatment is not backed up with field visits, simulation, demonstrations etc. Modern simulation tools can be used as an active learning tool, to augment class room teaching. Further, simulations results can be demonstrated without expensive infrastructure and drastically improve the level of understanding of the subject. This paper presents a systematic approach using simulation through PSCADTM, to enhance the teaching-learning experience of transmission line protection using distance relay with auto-recloser feature. The response of the protection system is studied and analyzed when a fault occurs in the system. Simple exercises are posed to augment the self-learning experience of the student to further strengthen the concept of the topic.

8. Reliability and survivability analysis of narrowband power-line communication links in low-voltage building network applications

Konark Sharma and Lalit Mohan Saini

Recent developments in power-line communication (PLC) based power automation and security systems are transforming into smart automation for low-voltage building network applications. This paper presents reliability and survivability analysis of G3-PLC compliant modems that aims to develop working pilot models for security as well as for complete NIT Kurukshetra campus buildings automation. In order to verify the proposed hardware design and implementation of G3-PLC system along with necessary theoretical background. Development of G3-PLC based virtual instrument to run-time couple local/remote monitoring and control of the building has been major outcome. The presented proposed design with open source platform, which is re-usable with requirement based customization, simple, user-friendly and validated through implementation. The system based on this logic can also be used for smart metrology meter (SMM) applications (i.e. metrological functions and real-time monitoring functions) and an effective tool for connecting the global consumers through energy efficiency and awareness corridor.

Vol. 11, No. 3, Sept 2015

Vol. 11, No. 3, Sept 2015

9. A novel approach to transformer differential protection using sequence component based algorithm

Dharmesh D Patel, Mistry K D and Chothani N G

This paper presents a new unit type protection for power transformer by combining differential protection and phase angle comparison of sequence components of currents. The simple differential protection scheme alone may ma-operation during current transformer (CT) saturation and high resistance internal fault conditions. Hence, the sequence component based phase angle comparison technique is combined with percentage biased differential protection scheme. Discrete Fourier Transform (DFT) is used to calculate the phase angles of sequence components and harmonics of primary and secondary current signals of transformer. Low pass butter worth filter is used to correct the current signals before passing it to DFT. During internal fault, the phase angle difference of primary and secondary current is very low whereas large angle difference observed during external fault/other conditions. The performance of the proposed algorithm has been evaluated by considering various transformer and system parameters. Numerous simulations are carried out on three phase power transformer using PSCAD/EMTDCTM software to validate the technique. The proposed algorithm perfectly distinguishes internal fault and external fault condition. Moreover, various situations such as magnetizing inrush current, high resistance internal fault and CT saturation conditions are also tested for validation.

10. Control of the reactive power supplied by a WECS based on an induction generator fed by a matrix converter

Ravindra G, Chengaiah C H and Chandra Sekhar B

This paper introduces an integrated energy storage and reactive power compensation in a large wind power plant, and it deals to regulate the reactive power supplied by a variable-speed Wind Energy Conversion System (WECS), based on an induction generator fed by a Matrix Converter (MC). The control strategy used in this paper is input current observer, implemented using an estimation of the modulation index, and a nonlinear control loop that regulates the displacement angle at the matrix converter input. This paper is described the implemention of the matrix converter to control the reactive power by using the Space Vector Pulse Width Modulation (SVPWM) technique in large wind farms and combining them into one system to maintain stability control of the wind power plant. Control of reactive power increases the regulating capacity, which can provide voltage stability in the wind farm. In this work, Matlab/SimulinkTM model and simulation of the three phase matrix converter have been performed using the space vector control algorithm. The algorithm uses a simpler method than the other control algorithms to control the input power factor. To verify the performance of the proposed Matrix Converter, modulation strategy, and control design methodology, various simulation results are presented.

11. Reliability constrained optimization of SAHPS using markov based GA and PSO

Manohar Potli, Chandra Sekhar B, Balachandra J C, Babu Yadav Y and Sekhar V

Renewable energy resources like wind, solar, biomass, tidal, hydropower and geothermal constitute a type of power generation and received much attention as alternatives for conventional power generation. Renewable Energy Resources (RER) will help to mitigate the emission of greenhouse gases. In this paper, a study on reliability constrained optimization of Small Autonomous Hybrid Power System (SAHPS) is carried out. It consists of the 10 kW wind unit, 5 kW solar unit, 5 kW pico-hydro unit and 20 kW diesel unit. Hourly speed of wind, solar radiation and water discharge and load profile is obtained using data synthesizer. The objective function with cost and the number of units and reliability constraint is formulated. Cost minimization and optimal sizing of SAHPS is performed using Genetic Algorithm (GA) and Particle Swarm Optimization (PSO). Later markov models for the wind, solar, pico-hydro and load profile with transitions among all states are developed. Markov models are integrated with GA and PSO techniques to minimize the total cost and get the best combination of generation units. All the above analysis is carried out in the MATLABTM software environment. Results for chronological method and markov method will be presented and analyzed.

12. Solar PV based switched reluctance motor drive for low power medium speed applications

Vani Vijay, Reeba S V and Sudhir Kumar R

Solar Photovoltaic (SPV) is the most important renewable energy source which is gaining importance in all fields of electrical utility. Utilization of SPV source in electrical drives applications can bring about a considerable change in the present day energy crisis. Here an SPV based Switched Reluctance motor (SRM) drive is presented which can be utilized in low power high speed and medium speed applications. SRMs have inherent advantages of low inertia, low rotor losses, robustness and simple construction. The operation of the converter circuit is with respect to the reluctance variation of the rotating machine which makes it different from other drives. Here a converter circuit is designed for the operation of SRM from SPV source. The SPV characteristics are different from a constant DC source since the output power and voltage varies with insolation and temperature. The proposed system is verified using LabVIEWTM Simulation and the results are discussed.

Vol. 11, No. 3, Sept 2015

Vol. 11, No. 3, Sept 2015

13. Review of three port micro-inverter with power decoupling capability for photovoltaic (PV) systems applications


The Photovoltaic (PV) systems have been realized using different architectures, starting with the string and centralized PV system to the modular PV system. Presently, decentralized inverters are being developed at the PV panel power level (known as AC – PV Modules). Such new PV systems are becoming more attractive and many expect this will be the trend of the future. The AC-Module PV system consists of an inverter attached to one PV panel. This integration requires that both devices have the same life-span. Although, the available commercial inverters have a relatively short life-span (10 years) compared to the 25 –year PV. It has been stated in literature that the energy storage capacitor (electrolytic type) in the single-phase inverter is the most vulnerable electronic component. Hence, many techniques such as (power decoupling techniques) have been proposed to solve this problem by replacing the large electrolytic capacitor with a small film capacitor. This paper will present a quick review of these power decoupling techniques, and proposes a new three-port micro-inverter with power decoupling capability for AC-module PV system applications.

14. Single exponential smoothing approach for 5 MW solar power plant generation forecasting

Vikas Pratap Singh and Pratap Srivastava

In 21st century forecasting of solar power generation is an important issue due to grid integration. So solar power and conventional power are basic sources of grid integration. Solar power is playing a key role in grid integration. In this work, Solar power generation forecasting is carried out based on the data collected from a 5MW Gujarat Power Cooperation limited solar photovoltaic power plant which is installed in Charanka, Gujarat. In this paper we discussed about the single exponential smoothing for solar power forecasting problem.

15. Regression models in wind power forecasting

Anuradha M, Keshavan B K, Ramu T S and Sankar V

Modeling of generation of wind power systems is useful for an effective management and balancing of a power grid, supporting real-time operations. Forecasting the expected wind power production could help to deal with uncertainties. In comparison with the mathematical approach, the data driven approach is useful where both detailed information about the system and real time measurements are unavailable. Winds being a natural phenomenon, statistical methods are more suitable for wind power plants than that of conventional power plants. In this paper, the data on the wind speed and power generated from a location in the state of Karnataka, India, has been analyzed and shown that the probability distribution of wind speed follows Rayleigh or Gaussian/Normal distribution. Short-term wind power forecasting is carried out using Autoregressive models.

16. A novel high step-up DC-DC converter combining KY and CUK converters for fuel-cell system applications

Sowmya K P and Rajkumar G

A novel high step-up DC-DC converter which combinig KY and CUK converters for fuel cell system applicationshas been proposed in this paper. The voltage conversion ratio is greater, which combines one KY converter, one CUK converter and one coupled inductor with the turns ratio. The proposed converter consists of two-phase version configuration. A CUK type converter is integrated to the first phase to achieve a much higher voltage conversion ratio and avoid operating at extreme duty ratio. In addition, additional capacitors are added as voltage dividers for the two phases,which provide a boost operation for the second phase this proposed converter. So, the second phase of the proposed converter is a boost circuit. This converter possesses high gain ,non-pulsating output current, and also reducing the output voltage ripple. A detailed description of the proposed converter is presented along with a simple mathematical deduction and some experimental results. Finally, prototype system is also constructed to verify the effectiveness of the proposed converter.

17. A study on co-gasification of high ash Indian coal with petcoke in a fluidized bed gasifier

Tirupathi Naidu Ch, SivaramaKrishna N, Nagamohan I and Satyamohan Rao D

An investigation has been undertaken to study the co-gasification of high ash sub bituminous Indian coal with petcoke in a bubbling Fluidized Bed Gasifier (FBG) system. The objective of this work is to study the effect of petcoke content in coal blend feed on gasification characteristics by carrying experiments in a pilot scale 1.2 T/d FBG (I.D. 0.2m X height 4.2m) system using air and steam as gasifying agents. The gasification characteristics include cold gas efficiency, carbon conversion, calorific value and composition of synthesis gas (syngas).Reactivity study carried in High Pressure Thermo Gravimetric Analyser (HPTGA) shows that coal blend reactivity decreases with increase in petcoke content in it. Gasification results indicate that increase in petcoke content in blend leads to decrease in carbon conversion and syngas calorific value which could be attributed to low reactivity of petcoke. A very low carbon conversion and syngas calorific value for petcoke gasification indicate that it may not be viable to gasify petcoke in FBG system.

Vol. 11, No. 3, Sept 2015

Vol. 11, No. 3, Sept 2015

18. Realistic estimate of water hold-up, circulation and consumption in solar concentrating thermal power plants

Siddhartha Bhatt M

This paper presents a comprehensive analysis of water utilization in concentrating solar thermal (CST) thermal power stations (TPS) keeping in mind the experience of operating coal plants. The water utilization is divided into three modes: water hold-up, water circulation and water consumption. The water hold-up and circulation represent the minimum quantity of water required for running a power plant with a few days autonomy. The water consumption represents the extent of replenishment required on a continuous basis. On the basis of quality, the consumption can be classified into: raw water, soft water and demineralized (DM) water. The reserve hold-up in a CST station of 1 GW is around 0.95 to 1.05 million m3 per GW which corresponds to 9-10 days consumption. The working hold-up inside the plant is 0.27 million m3 per GW. The water circulation rate for a 1 GW CST station is 7500 m3/h or 0.18 million m3/day. The major water consumption which is not generally tracked or measured is conveyance loss between the raw water intake source and the power station intake point which can be as high as 30 %. Loss of DM water directly affects the energy efficiency as it mostly represents the high quality steam lost from the system and has a high cost of production.

19. Thermal and dielectric performance of melt processed polycarbonate /CaCu3Ti4O12 composites

Thomas P, Vynetheya S and Girish M. Joshi

Composites comprising Polycarbonate (PC) and CaCu3Ti4O12 (CCTO) were fabricated via melt mixing followed by hot pressing by employing both micron (1-7µm) and Nano (75-100 nm) sized crystallites of CCTO. Both the micro and nano CCTO powders were self-synthesized using solid state and co-precipitation routes respectively. These were characterized using X-ray Diffraction (XRD), Thermo Gravimetric (TGA), Differential Scanning Calorimetry (DSC), Scanning Electron Microscopy (SEM),Impedance analyzer for their structural, morphology and dielectric properties. Nanocomposites inducted with nCCTO-50 wt% exhibited better thermal stability than that of pure PC and composite embedded with micron sized CCTO. However, there was no significant difference in the glass transition (Tg) temperature between the polymer and the composites. The Nano composites (PC+nCCTO-50 wt%) exhibited 2.5 times higher permittivity values as compared to that of composites having 50 vol% micron sized CCTO crystallites.

The Journal of CPRI, Vol. 11, No. 4, December 2015

ABSTRACT LIST


1. Effect of TCSC on power system stability


In FACTS devices supplementary signals are widely used to mitigate sub synchronous resonance in power system. Sub synchronous resonance occurs due to series capacitor in the power systems. In this paper Effect of TCSC on power system performance is studied and it is shown that TCSC can bring down SSR frequency and at high value of series capacitive reactance it can stabilize all the modes of turbine- generator set without supplementary signal. The study system is IEEE first benchmark model. Modeling of IEEE first benchmark model with TCSC is also presented in this paper. Small signal stability and Large signal stability both are carried out in this paper.

2. Simulationandexperimentalvalidationofelectrostaticfielddistribution under existing 765 kV transmission line

Dundru Sridhar, Kanyakumari M, Jithin Pauly P, Karunakara K and Vasudev N

In this paper, comparative analysis of computed and measured lateral profiles of electric field distribution at maximum sag point has been done for the existing 765 kV AC transmission line located at northern region of India. Computations were carried out by using developed MATLABTM Program. Measurements were carried out by using electric field meter designed in CPRI. Right of way is also determined for both computed and measured values of electric field based on safety limits given by Central Electricity Authority (CEA). Measured quantities compared with computed electric field. From the obtained results it is observed that, measured right of way is almost matching with computed right of way and there are few differences between computed and measured values. Possible reasons are explained for the causes of differences.

3. High Voltage Direct Current (HVDC) extruded cable - An overview

Nageshwar Rao B

High Voltage Direct Current (HVDC) cable has the ability of transmitting electrical energy over long distances in an economical way, with improved stability and reliability. HVDC Cable also provides a compact and low-loss transmission power line, in comparison with the conventional cable made out of copper or aluminium. The design of insulation for HVDC extruded cables is one of the most challenging issues, mainly due to the dependence of its dielectric properties on temperature, electric field distortion due to accumulation of space charge in the insulation. However, there is a great potential for development of extruded HVDC cables globally. This paper reviews the development of HVDC cable for electrical power transmission around the world, new materials for HVDC extruded cables, issues with space charges,methods for measurement of space charges and qualification tests on HVDC cables.


4. Studies on aircell in a conservator tank

Madhu Palati

Power is transmitted at high voltages to reduce the transmission losses. Power transformer is used at generating and intermediate substations to step up and step down the voltage to the required levels. Transformers above 10 MVA are fitted with air cell in conservator. Non-linear loads connected to the system induce harmonics into the system resulting in rise in hot spot temperature and oil temperature which dictates the ageing of insulation. This paper discusses in detail the need of air cell in conservator, advantages and causes for the failure of Air cell.

5. Fault analysis of power transformers from north eastern region by dissolved gas analysis

Manas Chakraborty

The Dissolved Gas Analysis (DGA) is an effective technique for transformer fault diagnosis in oil-immersed transformers. The presence of certain key gases is monitored and quantified. Numbers of methods are used to analyse and interpret the gases formed inside the transformer. Key gas, rogers ratio, IEC ratio and Duval Triangle are the most frequently used methods. The DGA data of around 255 power transformers from the utilities of the North Eastern Region are analysed to interpret the transformer condition. The types of fault and their probability with transformer service life, power and voltage ratings are discussed.

6. On choice of velocity for acoustic-emission linear-source-localizationin metallic medium

Deepthi Antony, Prasannajit Sahoo and Gururaj S Punekar

Acoustic emission (AE) testing is a recognized Nondestructive Test (NDT) to detect and locate flaws in mechanically loaded structures. As the component is subjected to mechanical loading, discontinuities in the components release energy, part of which is converted to sound. In this paper an experiment is conducted to detect and locate the source of acoustic emission (due to pencil lead break test) on a metallic strip. The knowledge of velocity with which the AE signals travel in the metal medium is very crucial in detecting the exact location of the AE source. The effect of velocity error in location detection is studied by conducting ‘event’ analysis with different velocities, using experimental data. This experiment uses the principle of difference in arrival time of the AE signal at each sensor for location detection. Results are supposed to give better understanding of AE based Partial Discharge (AEPD) anlysis, which involve structure borne paths.


7. Evaluation of high voltage rotating machine stator insulation system using diagnostic tests

Ramesh P Nair and Sumangala B V

The reliability of any high voltage equipment depends to a large extent on the insulation quality. And in high voltage rotating machines, the stator insulation is an important part with respect to the manufacturing cost as well as maintenance and lifetime aspects. During operation, insulation is subjected to one or combination of electrical, thermal, mechanical and environmental stresses. The insulation ages over time due to these stresses and eventually fails. These unexpected failures can be avoided by conducting diagnostic tests. From the diagnosis results the extent of insulation degradation can be quantified and necessary actions could be planned to avoid in-service failure of vital machines and thereby enhancing the reliability. Every diagnostic test gives a certain information about the insulation condition. In this paper, the significance of diagnostic tests are discussed and how these tests can be used to evaluate the insulation condition is presented.

8. Rotor initial position detection schemes in synchronous machines

Sreeram V, Gopal D H and Arun Babu M

Before the advent of power electronic drives, synchronous machines were started as induction motors and brought close to synchronous speed before pulling into synchronism. The introduction of power electronic drives brought a revolutionary change with variable frequency drives becoming the most preferred. Starting the machines still remained a challenge as wrong alignment of the stator space vector can lead to failed start or even in worst case, reverse rotation. Several techniques have been used to detect the initial position of the rotor for proper alignment of stator space vector. Most of them have been based on position encoders while the current trend favors sensor-less, machine model based methods. An examination of the philosophy of sensor-less methods is carried out in this paper with measured results from the 2500 MVA short circuit generator at the High Power Laboratory at CPRI, Bangalore. The determination scheme based on simple machine equations has been found to be excellent in predicting the rotor position.

9. Effect of climatic conditions on the performance of solar PV inverters

Vani Vijay, Sudhir Kumar R and Pradeep K

Electrical equipment designed for a particular environmental condition may not provide satisfactory performance under other conditions of temperature and humidity. Specifically in the case of solar PV inverters, the efficiency and other system characteristics may vary as per the extreme climatic conditions at the place of installation. Here a comparative study of solar PV inverter performance under such extreme conditions is presented in terms of system efficiency and insulation resistance. The conditions as per relevant international standards are simulated in a climatic chamber and five samples are studied for the effect of extreme temperature and humidity conditions. It is found that the insulation resistance of few samples is varying drastically which will affect the system safety. Similarly the efficiency of the system is also affected. Similarly there is considerable change in the system efficiency also.


10. A review on multilevel inverter: topologies, control strategies and application

Vinoth Kumar N, Kumar Chinnaiyan V, Pradish M and Divekar M S

Multilevel inverter is an attractive alternative for traditional two level inverter. It has many advantages over traditional multilevel inverter such as lesser voltage stress on switches, lesser filtering requirement and is free from electromagnetic interference EMI issues. It is being applied successfully in various medium power application such as AC power supplies, drive systems, and Distributed Energy Resources area (DER). In this paper, a review of multilevel inverter is addressed such as various traditional topologies, reduction of power switches,modulation, control strategies, and application. The control and modulation techniques such as Pulse Width Modulation (PWM) Techniques, space vector modulation (SVM) are described. Selective Harmonic Elimination (SHE) with mathematical modelling is addressed in detail. SHE-PWM is preferable as it operates at very low frequency and eliminate the lower order harmonics without any filtering circuit and reduction of switch count ensures higher efficiency with reduction of cost.

11. A comparative analysis of multi-carrier PWM schemes for grid integrated 15-level smart inverter topology via several intelligent controllers

Hemachandu P, Veera Reddy V C and Chandra Sekhar B

Renewable energy plays a prominent energy which comes directly from natural resources like as fuel cells, PV arrays, wind, rain, tides and geothermal heat. These general resources are renewable and can be naturally replenished. Therefore, for all practical purposes, these resources should be considered to be inexhaustible, unlike dwindling classical fossil fuels. The grid integrated system is merely interpretation of stand-by module to co-generation scheme; it combines the both PV/FC arrangement as a single module with a highly recognized power conditioning system. The module ranges an outcome of 100 V to 400 V from 10 V to 40 V input, incorporated to micro-grid system via proposed asymmetrical inverter topologies with intelligent controllers. This controllers forecasts the optimal modulation index and switching angles for attaining enhanced output voltages, in-limit THD resolution and averts the sudden variations. In this behaviour, the proposed scheme provides perfect sinusoidal grid voltages which are in-phase with the current, good harmonic limitation values. Finally, a simulink model is implemented to validate the appearance of proposed 15-level asymmetrical inverter topologies with intelligent controller by advanced modulation schemes using Matlab/SimulinkTM platform and results are conferred.


12. DesignofLCLfilterformicroinverter


Thepresence of Distributed Resources (DR) and the subject of Distributed Generation (DG) are rapidly growing in modern distribution networks. Many of these resources use renewable energies, and many of them provide electrical energy in the form of dc voltage source. Consequently, the connection of such resources to the utility grid needs a dc/ac conversion stage. Voltage Source Converters (VSC) are widely used for this application as they have a mature technology. These converters are usually connected to the utility grid through a simple L filter to reduce the current harmonics injected to the grid. However, higher order filters, like LCL filters, can provide better harmonic attenuation and reduce the filter size at the same time. This paper proposes a method for LCL type filter design, which makes the task very convenient. Step-by-step design procedure is described as a design example, which is verified by simulation.

13. Run-of-the-river micro hydroelectric power generation from artificiallyinducedvortices

Aravind Venukumar, Nandakumar M, Venkateswara Rao M and Shekhar Kumar M

Run-of-the-river micro hydroelectric power systems are a purely green form of renewable energy generation. In the case of a run-of-the-river hydroelectric power generation scheme, there is absence of an energy storage device (like dam) to allow manipulation of the mass flow rate to efficiently extract power. The postulation of presenting a vortex as a kinetic energy storage device analogous to a flywheel to extract power in run-of-the-river generation is introduced here. Studies show that Coriolis force is a major factor in vortex formation, but its effect in artificially induced vortices for power generation is negligible owing to high Rossby number .This paper discusses various aspects in the realization of power generation from artificial vortices and how to utilize artificial vortices for micro hydroelectric power generation with water head as low as 1 meter. The low head requirement makes the technology a viable option for decentralised cascaded power generation and community electrification.

14. Relation of critically refracted longitudinal wave (LCR) velocity with graphite nodularity and matrix in ductile iron

Malur N Srinivasan, Robert J Bennett and Don E Bray

The results of an investigation conducted to study the relation of critically refracted longitudinal wave (LCR) velocity with graphite nodularity and matrix in ductile iron are reported in this paper. The relation between LCR velocity and graphite nodularity was studied using as-cast test bars obtained from one foundry. Three groups of test bars of similar nodularity obtained from a second foundry were subjected to heat treatment so as to obtain ferritic matrix in the first group, martensitic matrix in the second and tempered martensitic in the third, to enable the relation of LCR wave velocity with these matrices to be studied. Also three other test bars from the second foundry were subjected to annealing, normalizing and quenching and grouped with an as cast test bar of similar range of nodularity, to evaluate the residual stress developed in each case. The approach followed in this investigation enabled qualitative assessment of the effects of graphite nodularity, matrix and residual stress on the LCR velocity in ductile iron.


15. Assessmentofwaterwalltubesofafossilfuelfiredthermalpowerplant

Arvind Kumar, Malabika Roy, Janardhana M and Shekhar Kumar M

Boilers being the heart of any steam generating system, failure of its components,will lead to forced outages ofthe plant, resulting in heavy economic losses in terms of non–availability of plant.Periodic inspection and assessment of boiler tubes has a great impact on the generation of power and economic status. The assessment of boiler tubes minimizes the risk of forced outage of the power plant. This paper presents the assessment of water wall tubes of thermal power plant to avoid any forced outage due to failure of water wall tubes. The assessment includes non- destructive, destructive and failure analysis of failed tubes. The periodic non-destructive evaluation is performed for the boiler tubes for generation of data for assessing and deciding the integrity of the boiler tubes. Destructive and failure analysis of failed tubes gives the information and helps in identifying the root cause of failure and to take preventive action for avoiding forced outage.

16. Effect of moisture in coal on station heat rate and fuel cost for Indian thermal power plants

Siddhartha Bhatt M and Rajkumar N

Indian coals inherently contain low inherent moisture (IM) (5.5-9.5 % with an average of around 7.5 %) and moisture addition is through the surface moisture (SM) due to sources external to the coal. On the other hand imported coals contain very high IM (15-25 %) but negligible SM. Presence of surface moisture (SM) is a major liability to the power generating process and it’s and control needs to be understood on a broader national perspective. Great importance must be given during the transportation, handling, transfer and storage of coal to ensure that its heating value is preserved and there is no deterioration on account of SM addition enroute to the power plant or in the coal yard storage prior to its entry into the furnace of the boilers. It is the SM which affects the power plant operations. In the case of imported coals higher total moisture (TM) coals (higher inherent moisture and almost no SM) are cheaper and the marginally increased generation cost due to IM is offset by the cheaper purchase price. The same is not true for Indian coals where there is no provision for cost accounting of SM except for upper limits. The impact of 1 % TM (without considering the weight effect) is -4.2 kcal/kWh on design unit heat rate, -8.2 kcal/kWh on operating unit heat rate, -0.0226 p.u. of plant load on Station load, -4.0 % on Plant load factor,+0.2263 % of plant load on Auxiliary power, +0.0079 kg/kWh on Specific coal consumption,+1.1426 ml/kWh on Specific fuel oil consumption and +15.21 kcal/kWh on Station heat rate.


17. Analytical uses of polyaniline in power application: a review on recent development

Moumita Naskar

Polyaniline (PANI) and its derevatives are the upcoming materials in power application. They have several advantages due to their electronic and optic properties compared to the non-conducting polymers. The research interest on conducting polymers has been increased due to their reasonably good conductivity, good environmental stability, easy preparation techniques and redox properties compared to other organic compounds. Among the conductive polymers PANI and its derivatives invite more attention for their excellent adhesion and anticorrosive properties also. PANI can be used in rechargeable batteries, fuel cell, super capacitor, pH and gas sensor etc. This article aims to provide a short overview of the present status of research on synthesis, characterizations, development and applications of PANI and its derivatives.

18. An approach to thermal analysis of current transformers of rating 170 kV and above

Viswanatha C and Rakesh K G

Current transformers are core of electrical systems functioning to provide required inputs for metering and measurement purpose. Generally the current transformers are tested for electrical integrity by way of di-electric measurements such as capacitance tan delta, partial discharge, accuracy and others. Although these tests fairly determine di-electric / insulation co-ordination of current transformer they do not reveal thermal condition of current transformers. In this study attempts are made to understand thermal integrity of current transformers by way of temperature measurements and temperature rise of primary and secondary winding which are main constituents of current transformers. The current transformers though are of different type such as winding, bar type, window. The thermal performance is equally important for all these types of current transformers. The general approach is to measure temperatures at accessible regions such as tank surface if it is live tank type current transformer and also at the axel points of protruding outside the tank which are internally connected to conductors. The temperatures before energizing of current transformer and after temperature rise test are measured by resistance method in accordance with international standards. In this work, temperature mapping at steady state for several current transformers of 200 kV rating have been studied in the light of IEC standards and results are more discussed and analyzed to determine the thermal condition of current transformers.

The Journal of CPRI, Vol. 12, No. 1, March 2016

ABSTRACT LIST


1. ATC enhancement by incorporating FACTS devices for deregulating scenario in present power market

Jeslin Drusila Nesamalar J, Bavithra K, Charles Raja S and Venkatesh P

The cost based monopolistic power market rules are new fangled by the word deregulation. Trepidations in its conceptualisation and integrated operation in the impending scenario are transmission pricing, congestion management and Available Transfer Capability (ATC). Of this intriguing technical challenge, ATC is the one that needs to be interrogated and dogged to make open access a feasible obsession for private entity participation which is deregulation’s intention.

This research work aims at calculating ATC using non iterative, simple, Power Transfer Distribution Factors (PTDF) based methodology, enhancing them using Flexible AC Transmission system (FACTS) devices like Static compensator (STATCOM) and Unified Power Flow Controller (UPFC). A proven alternative to overcome extravagance by erecting new transmission facility is incorporation of FACTS devices in the existing structure that indulge in reactive power compensation. These FACTS devices are modelled using the power flow equations and is placed optimally based on the slope of sensitivity factors.

The optimal settings of FACTS devices is obtained by a soft computing technique labelled as Particle Swarm Optimisation (PSO) to enhance the ATC for the assumed bilateral and multilateral power contracts. The voltage and angle of shunt and series FACTS devices are randomly generated as the population of PSO on sample 6 bus and standard IEEE 30 bus systems.

2. Dynamic operation and control schemes for hybrid static synchronous series compensator

Raju J, Kowsalya M and Arunachalam M

This paper presents a modeling and simulation of Neutral Point Clamped (NPC) Voltage Source Converter (VSC) based Hybrid Static Synchronous Series Capacitive Compensator (HSSSC) with direct and indirect control schemes is presented. The hybrid scheme is a combination of Static Synchronous Series Compensator (SSSC) and a fixed capacitor in series with the transmission line. The hybrid scheme is reduces the size and ratings of the SSSC in a transmission line system. The effectiveness of the schemes is to analysing the performance characteristics of HSSSC with direct and an indirect controller is evaluating using the MATLAB/SIMULINKTM.


3. A bottleneck-free bidding zone configuration approach qualification

Deep Kiran, Abhyankar A R and Panigrahi B K

Nodal or zonal price signals are generated in a power network based on prevailing market philosophies. In nodal pricing regime, prices are derived at each injection or withdrawal node. These prices will vary across the network based on congestion and losses in the network. In financial market context, network is considered to be lossless. Thus, occurrence of congestion in the network creates different prices for electricity transactions. This is known as bottleneck issue. However, in zonal pricing regime, the complete network is present as a single zone in the absence of any bottleneck. In practice, market splitting takes place in presence of bottlenecks in the network. This is an attribute of power market that has been adopted in decentralized market clearing practice, the example of which are Indian power market and Nordic pool. The market splitting is done based on pre-specified zones that are fictitious and formed based on regulator’s experience. These zones are termed as copper plate in which all players are treated on par as they are connected to a single bus having a single price for buying and selling of power. It is expected that players enjoy enough market liquidity and risk hedging to play freely within a zone to have perfect competition. In India, these zones are formed based on geographical and political boundaries. This might bring the players who are non-contributors of congestion into the wing of high price zone. This creates an issue of fairness. This paper proposes a methodology to solve network segmentation problem in wholesale competition environment so that appropriate bid areas are formed. A two-step process is proposed. Firstly, an optimization based zone formation of nodes with closeness as a decision index is done. Secondly, a fine adjustment on the results of the first step by bus migration process is done. The proposed method is implemented on modified Indian power network consisting of 193 buses, 452 branches and 52 generators. It is observed that a clear-cut and practically implementable bidding zones are formed using this method.

4. A systematic approach towards developing prototype of AMI based DSM model for load management

Manju Gupta, Sushma Gupta and Tripta Thakur

Participating in demand response has significant advantages for both consumers and electricity producers, i.e., saving on high electricity prices for the user and helping utilities in peak load curtailment. Further increased the use of renewable energy and energy storage, along with the need to increase energy efficiency are the main driver for the implementation and utilization of DSM. In DSM to monitor and control of the low voltage power grid, a computer system (a combination of hardware and software) is provided which is advance controlled by SCADA (Supervisory Control and Data Acquisition) System. Next generation application and DSM concept are important with smart grid to give the answer to the need of the changing power system. This research paper insights the development of advanced metering infrastructure based demand side management model for load Management. The main objective of this application is consumption optimization and automation in operation. This paper proposes a fixed load control strategy with fixed forecasted photo voltaic generation, battery storage system and priority based load curtailment mechanism.


5. Field computation of efficiency of induction machine working on unbalanced conditions using modified non-intrusive air-gap method

Grewal G S and Rajpurohit B S

Various techniques have been suggested for efficiency estimation of Induction Machines (IMs) with different levels of intrusion and accuracy. Traditional methods depicted in IEEE Standard 112 can’t be employed for industrial environment where continuous industrial processes are in occurrence. This paper put forth an approach for non-intrusive air gap torque evaluation for efficiency estimation of IM by utilizing IM terminal quantities like input voltages and input currents. Base difference between Method-E and air-gap torque method is discussed. In vector control system, the speed estimation of IM is done based on Model-Reference Adaptive System (MRAS) by utilizing input electrical quantities and instantaneous reactive power. Algorithm used does not need intrusive no load testing. Experimental validation is carried out to verify the effectiveness of the proposed structure.

6. Performance analysis of distribution static compensator for power quality perspective

Sanath Saralaya and Manjunatha Sharma K

In recent years the use of nonlinear loads in the distribution system has increased drastically. Due to these nonlinear loads, power quality problems occurs in the system. Distribution Static Compensator (DSTATCOM) is a voltage source converter based shunt connected custom power device, used in distribution system for performance improvement. DSTATCOM will maintain constant voltage at load terminals and limit the Total Harmonic Distortion (THD). This paper presents a case study on investigation of performance of DSTATCOM at different operating scenarios. IEEE 13 bus industrial system is used to study the performance of three leg DSTATCOM. Voltage control mode with PI controller is used to control RMS voltage at Point of Common Coupling (PCC). PSCAD/EMTDCTM tool is used to study the performance. From the study it is found that DSTATCOM is able to maintain voltage at 1 pu.

7. Power quality issues in steel re-rolling mills in India

Deepak S Jain, Manas Kundu and Mohan V Aware

The steel re-rolling industries are one of the major industries in the world. As they are growing with very fast rate with an increase in demand, their power quality problems are also increasing with the same rate. This paper presents these power quality impediments, its causes, effects and solutions. This paper encourages the organizations who deal with international standards to develop some standards for controlling these kinds of problems. Real time measurements and simulation modelling both have been presented in this paper, for the steel re-rolling industries and their results have been compared.


8. Optimal placement and sizing of active power line conditioners

Saranya V and Kavitha D

In this paper, a problem of allocation and sizing of multiple active power-line conditioners (aplcs) in power systems is handled with novel formulation. The utilized objective function comprises two main factors such as reduction of total harmonic distortion and the total cost of active power-line conditioners (aplcs). The formulated problem is solved by optimization technique Shuffle Frog Leap Algorithm (SHFLA) using MATLABTM. To evaluate the competence of the proposed formulation, the IEEE 18-bus distorted distribution test system is employed and investigated with various number of aplcs placement. These cases are based on the discrete and limited size for aplcs, requiring the optimization method to solve the constrained and discrete nonlinear problems. The comparison of results in this paper showed that the proposed SHFLA is the most effective result among others in determining optimum location and size of APLC in distribution systems.

9. ANSYS-Maxwell based design of high frequency link for grid connection of renewable energy sources using MLI

Rekha Agrawal and Shailendra Jain

Currently, high frequency transformer for power MLIs is used for renewable energy interfacing applications. With the advancement in magnetic materials properties have led to the development of high frequency transformers for converters. Recently high frequency based magnetic material offers high saturation flux density and low core losses, used for designing of compact, light weight and efficient transformers. However, the designing of magnetic material is based on electro-magnetic concepts. So here, electro magnetic based software “ANSYS-MaxwellTM” is used to design a high frequency transformer in 2-D geometry. The design methodology is illustrated to optimize it with minimum core losses, copper losses in the high frequency transformer.

10. Multiple feedback-control-loops for single-phase full-bridge PWM inverter

Jora M Gonda and Londhe Apurva A

This paper presents a multiple feedback-loop-control technique for a single-phase full-bridge PWM inverter with output LC filter. The main challenge for an Uninterruptible Power Supply (UPS) is to maintain a high quality sinusoidal voltage under non-linear load conditions as most of the electronic loads are non-linear in nature and for that it needs to be controlled. Multiple feedback consists of two control-loops; one for capacitor voltage and other for inductor current-control. Output voltage and load curren-feedforward-control is used. This technique reduces the distortion in the inverter output voltage and brings it closer to a sine wave. The control concept has been verified using Matlab/SimulinkTM toolbox and the simulation results are obtained with different types of loads.


11. Optimal sizing and allocation of energy storage in wind power incorporated optimal power flow

Ulagammai Meyyappan and Kumudini Devi Raguru Pandu

The rapid expansion of wind power creates new challenges for power system operators and electricity marketers. Wind energy has the potential benefits in curbing emissions and reducing the consumption of irreplaceable reserves. But the variable nature of wind energy poses challenges in the power system operation and planning. In order to ensure the wind power as firm power, energy storage is added to smoothen the variations in wind power. In this paper, optimal power flow with wind and energy storage is developed. The Energy Storage Systems (ESS) are installed as a backup of wind generators to meet the demand reliably. The objective is to minimize the loss by optimal location and sizing of ESSs. With the optimally located ESSs, OPF is carried out using SFLA and tested on IEEE 30 bus system.

12. Design and analysis of small wind turbine parameter and output characteristics

Satpathy A S, Kastha D and Kishore N K

Small wind turbines have emerged as a pivotal source for powering stand-alone and offgrid loads. The power rating of such turbines is less than 10 kW. Such turbines operate at a very low value of reynolds number for which the mechanical output characteristics are very much different from that of its MW class counterpart. As a result, it is essential to design the parameters of the turbine. Further, it is imperative to model the small wind turbine behaviour in order to design a suitable control topology for interfacing the Wind Energy Conversion System (WECS) with the load. In this paper, an algorithm is presented to obtain the parameters and mechanical performance of a 3 kW wind turbine. The analytically obtained characteristic is validated against experimental characteristics reported in literature.

13. Interval optimization technique for the coordination of hydro units with wind power generation

Oshiya Arputharaj and Lakshmi Kaliyappan

In the deregulated electricity market, the power generators profit depends on its unit scheduling, bidding strategies and on the market price. The coordination of wind energy with other renewable resources serve an effective way for the generating companies to increase its payoff. Accordingly, the wind power with hydro power system coordination incur the enhancement of power dispatch and thereby reducing imbalance prices. This paper proposes an interval optimization technique to solve the price based unit commitment problem. It also suggests to solve the bidding strategy with the accurate intervals. Variations in wind hydro power, the volatilities in day ahead energy price, intra hour energy price are considered as periodic numbers. Comparing to the conventional technique it is easier to determine and optimizes the entire profit intervals. Henceforth, has an inherent advantage on computational complexity and associates under worst case scenarios.


14. Closed loop control analysis of half-bridge 1] resonant converter based battery charger

Sumanta Kumar Show and Parthiban P

Series Resonant Converters (SRC) popularly known as Line Level Controlled (LLC) converters are the most suitable topology of DC-DC power supply. The closed loop voltage regulation of a Half-Bridge (HB) Line-Level-Controlled (LLC) converter using PI controller is presented in this paper. Major objective of PI controller is to modulate frequency and duty ratio of gate signals. A voltage controlled oscillator (VCO) is generating the gating signals which will drive the MOSFETs for getting a regulated output voltage. The optimum LLC switching frequency ranges are derived so that converter can operate at higher efficiency. In this converter the primary switches (MOSFET) are operated with Zero Voltage Switching (ZVS) and secondary switches (Diodes) with Zero Current Switching (ZCS) to have lower losses and hence to obtain higher efficiency. Finally the theoretical results are verified by simulating the converter in MATLAB1/SimulinkTM circuit Simulator. The results obtained from simulation clearly signify the controller performance for adjustment of output voltage in case of variation in input line voltage and output current through the load. If the above observations are looked closely then it clearly indicates that the controller is executing the functions of regulating the output voltage. Whenever there is any variations in input line and output load then the output voltage across the load is able to follow the reference signal.

15. Novel load emulation technique for performance evaluation of isolated solar PV system under varying load conditions

Vani Vijay, Viswanatha C, Giridhar Kini P and Sudhir Kumar R

Solar Photo Voltaic (SPV) sources are widely used in present scenario of energy crisis for various applications including grid connected PV plants and grid isolated standalone applications. The performance of solar PV system is highly dependent upon the operating conditions of source and loads especially in standalone applications. The effect on various types of loads on standalone system can be easily analyzed at design stage and testing stage by using load emulation technique, where a virtual load is used to replace actual load, giving more flexibility and accuracy to loading conditions. Here a novel load emulator model is presented which can provide accurate variation in load power factor and THD compared to existing models. The converter decouples the current in to in phase and out of phase components and the in phase component can be regenerated. The model is simulated using MATLABTM simulation and the results are validated by comparing with experimental results obtained by loading SPV inverter with actual load. Hence the proposed load emulator is very useful in design and development of application specific solar PV systems and also for performance analysis of such systems based on various standards.


16. An integrated multi input DC-DC converter in hybrid energy system

Chandra Sekhar B and Sanjay Lakshminarayanan

In this study, an integrated double input DC to DC buck-buck boost converter for high/low voltage energy source applications is presented. An integrated buck-buck boost converter which can step down or step up the input voltage according to output voltage required at the load end. A multi input converter can be used instead of single input converters to integrate different energy sources such as solar PV, wind energy system, fuel cell and diesel etc. The converter is designed considering double input, in which same or different type of two inputs can be used individually or simultaneously. The operation modes and the steady state analysis of the converter are delinated. Finally converter behavior observed by using Matlab/SimulinkTM enviornment for closed loop simulation with PI control scheme, the obatinaed results are presented in detailed manner.

17. Steady-state DC conductivity of low density polyethylene with deep chemical impurity

Upadhyay A K and Reddy C C

This paper presents the effect of deep chemical impurities on the conductivity of insulating polymers. Although plenty of literature available to give conductivity model for insulating polymers but still there is a need of more accurate model. The authors try to propose a new theoretical model for mobility of electrons in order to understand the behaviour of electron towards deep chemical impurities at atomic level using quantum mechanical approach. Our model shows that chemical impurity plays an important role on conductivity of polyethylene.

18. A study on copper corrosion and its effect on dielectric properties of paper oil insulation of transformers using simulation and laboratory experiments

Daisy Flora S and Sundara Rajan J

This study investigates the impact of copper sulphide which is formed due to corrosive sulphur in mineral oil on dielectric properties of paper oil insulation of model transformer windings. The effect of copper sulphide on electric stress distribution is explained using FEM based electric field computations. frequency domain spectroscopy and insulation resistance measurements were carried out on the prototype transformer windings under conditions of copper corrosion at different temperatures and the variations in tan δ, real and imaginary part of complex permittivity (ε’, ε”), insulation resistance, and polarization index are discussed.


19. Analysis of particle movement and partial discharge in the winding of power transformer using CFD

Vasantha Gowri N, Srikanth P, Shashank V, Sankeerth G and Ramalinga Raju M

Power transformer is an important apparatus in electrical substation. It is therefore required that it should be protected against all types of undesirable events. It has been experienced that one of the reasons of failure of transformer is due to the presence of metal particles in the annular space between the windings. The particles during movement cause Partial Discharges (PD) due to the high voltage on the discs. The magnitude of PD depends on the particle nearness to the disk of transformer and stress developed on the metal particle. In order to determine the movement and stress on disc of transformer winding due to the presence of the particle, Computational Fluid Dynamics (CFD) analysis using FLUENTTM software is carried out. The winding considered for calculation is the high voltage part of the 200 kV transformer. Since the transformer is a two group winding only one half is taken for analysis due to symmetry. A particle of length, L = 0.5 mm and hemispherical radius of 0.25 mm is allowed to move in oil with flow velocity of 0.5 m/sec. the stress is calculated at various discs during upward movement of particle. A typical electrical stress obtained on the particle close to HV winding is 0.556 kV / mm. The particle considered for analysis is of spherical nature. Stress on the spherical particle is presented in this paper.

20. Electric and magnetic field simulation of polymer nano-composites for electromagnetic shielding effectiveness

Kavya M, Sundara Rajan J, Rashmi and Sailaja R R N

This paper discusses correlation between results of electric and magnetic field simulation using Finite Element Method (FEM) and laboratory measurements of electromagnetic shielding effectiveness. The study shows that the addition of the MWCNT filler to HDPE base matrix tends to increase the electrical conductivity and helps in reduction of the Electromagnetic field in terms of radiated emission. With the increase in the weight percentage of MWCNT filler, improvements in terms of reduction in electromagnetic field is achieved. Addition of nano nickel to the HDPE improves the shielding efficiency. The results of this study has helped in achieving the optimum filler concentration in HDPE nano composite for improved EMI Shielding effectiveness.

The Journal of CPRI, Vol. 12, No. 2, June 2016

ABSTRACT LIST


1. A study of electromagnetic induction in HVDC lines from parallel AC lines under short circuit conditions

Sreeram V and Sudhakara Reddy S

High Voltage Direct Current (HVDC) lines running parallel to AC transmission lines will encounter electromagnetic induction which will rise to substantial levels during a short circuit. The actual magnitude of induced current depends on several factors like distance between the lines, soil resistivity etc. The unenergised DC line will also have a voltage due to induction and the associated discharging equipment will have to carry the induced current. This paper attempts to study the levels of induction encountered by the HVDC line and associated equipment during a short circuit in the AC line. It was observed that magnitude of induced current during steady state and three phase fault did not exceed 5 A while the magnitude of induced current during single phase to ground fault exceeded 15 A.

2. Improving voltage and power factor using ANFIS in SVC for distribution system

Ramesh Babu U, Vijay Kumar Reddy V and Tara Kalyani S

Most of the electrical distribution systems are incurring huge losses due to the loads are wide spread, reactive power compensation facilities are inadequate and the reactive power compensation facilities do not have a proper control. A typical Static VAR Compensator (SVC) consists of capacitor bank in binary sequential steps operated in conjunction with a thyristor controlled reactor of the smallest step size. This SVC facilitates smooth control of reactive power closely matched with load requirements so as to maintain a power factor closer to unity. These types of SVCs require an appropriately controlled TCR. This paper deals with a reactor suitable for distribution system of 3-phase, 50Hz, and 415V with load P=25 KW, Q=21.23 KVAR system provided with FC-TCR Simulation which Compares results using Fuzzy Logic Controller (FLC) and Adaptive Neuro-Fuzzy Inference System (ANFIS) Controller. The effectiveness of the different controllers for improving the voltage stability limit, power factor and power transfer capacity of distribution system.

3. Design and implementation of a novel WAMPAC system for power network

Rajprasad R S

The proposed module is an innovative version, which is developed to prove as an effective alternative model to the existing modules of Phasor Measurement Units (PMU), ensuring feasible and reliable operation at very low design cost.

The intricate design and circuitry involved in the WAMPAC systems are replaced with a cost-effective equivalent module for distribution feeders. Remote monitoring and control of the system is effectively designed so as to reduce the involvement of manpower and ease the outlook of complexity in power system protection.


4. Design of impulse current units for master circuit breakers and make switches for use in high power application

Rajaboina Siva Kumar, Sreeram V, Gopal D H, Ramachandrappa V and Ramachandra B

The high power laboratory at CPRI has a short circuit generator of capacity 2500 MVA for the short circuit testing of power system equipment. The short circuit is initiated by the closing of Make Switch (MS) and is cleared by the Master Circuit Breaker (MCB). The closing operation of MS and tripping operation of MCB is to be completed in a very short duration of time. This requires a high magnitude impulse current to be injected in to the opening and closing coils of MCB and MS for their quick operation. For generating such an impulse current, a special impulse current unit is to be designed and fabricated. This paper presents the development of impulse current units for the fast opening and closing operation of master circuit breaker and make switch using Arduino Uno board.

5. Voltage stability constrained optimal power flow – a critical review

Telang A S and Bedekar P P

Power system researchers have looked upon the problem of Voltage Stability Constrained Optimal Power Flow (VSC-OPF) making use of classical and advanced methods of optimization. Many efforts have been made to optimize the power system by optimizing control variables of VSC-OPF problem for improving voltage profile. This paper compiles the significant developments made in the area of VSC-OPF using conventional and artificial intelligence based optimal power flow solution methodologies. After a thorough study of vast literature available on VSC-OPF, critical review with future scope has been presented to make the review study most focused and optimistic. Owing to poor speed and convergence characteristics of classical methods of optimization problem, intelligent computational methods have been emerged as one of the effective and efficient method. However, as an appropriate setting of control parameters involved in these meta-heuristic techniques is a key factor for success, the possibility of utilizing hybrid approaches should be considered for VSC-OPF problems. Another interesting feature of this study is that it is found that one algorithm cannot be superior to other algorithms in all kinds of cases; hence for the class of problem being studied, one has to find out which algorithm is better.

6. A novel Grey Wolf optimization algorithm for optimal DG units capacity and location in microgrids

Dinakara Prasad Reddy P, Veera Reddy V C, Gowri Manohar T and Chandra Sekhar B

Distributed Generator (DG) resources are small electric generating plants that can provide power to homes, businesses or industrial facilities in distribution feeders. By optimal placement of DG we can reduce power loss and improve the voltage profile. However, the values of DGs are largely dependent on their types, sizes and locations as they were installed in distribution feeders. The main contribution of the paper is to find the optimal locations of DG units and sizes. Index vector method is used for optimal DG locations. In this paper new optimization algorithm i.e. Grey wolf optimization algorithm is proposed to determine the optimal DG size. This paper uses three different types of DG units for compensation. The proposed methods have been tested on 15-bus, 34-bus, and 69-bus radial distribution systems. MATLABTM, Version 8.3 software is used for simulation.


7. A review on role of power electronics in electric vehicles: state-of-the-art and future trends

Shimin V V, Varsha A Shah and Makarand M Lokhande

In the current world scenario of increasing environmental issues and oil prices, development of Electric Vehicles (EV) have gained considerable importance and attention. Electrifying the conventional transportation system can reduce the use of depleting fossil fuels and can lead to better performance and reduced pollution. Power electronics will play a key role in making highly efficient electric vehicles which are low in emissions and having better fuel economy. This paper presents a review of the state-of-the-art power electronics technology in electric vehicles in detail focusing both semi-conductor devices as well as material technology. Also it discusses about the various power electronics systems placed in an electric vehicle. The paper concludes with a discussion of expected future trends in power electronics technology that will improve the markets for electric vehicles in coming years.

8. Interleaved flyback micro inverter based solar photovoltaic power generation system


PV generation is one of the fast growing renewable generation system to avoid the energy shortage. The micro-inverter system is best option for maximum energy harvest from each solar panel and easily we can expand the installed capacity. Now a day it is playing big role in rooftop system. These inverters divided as a single stage and double stage micro inverter. Compare to single stage double stage system having high efficiency with regulated waveforms. Interleaved flyback boost converter topology is used for improve the efficiency. Converter is high step up DC-DC boost with MPPT, MPPT is used to vary the duty cycle to generate maximum power from each panel both healthy and partial shading condition. MPPT voltage range from 27 V to 45 V, for 200 W, lower maintenance cost and higher energy yield with open-circuit voltage below 45 V. Micro-inverter PV system can achieve up to 25% lower energy cost compared to the conventional central inverter system.

9. A simple variable THD load emulation technique for performance evaluation of power supply equipment

Vani Vijay, Viswanatha C and Giridhar Kini P

Using load emulation, the performance of source side converters can be easily evaluated and improved without the need for actual load. Due to the increase in use of power electronic converters and SMPS based systems, the harmonic levels in load side has increased considerably. Hence emulation of variable THD load is very important in analysing the performance of source side converters and ensure the performance efficiency and power quality under such loads. Here a novel method of obtaining variable load using PWM control explained. The PWM is controlled in a rainbow sinusoidal fashion to obtain clipped waveform across a resistor so that harmonics is introduced in the Load. The power factor can also be varied in the system by paralleling it with leading and lagging converter circuits. The working principle, modelling and simulation are presented along with the results. Proposed technique provides accurate modulation of load THD and effect of harmonics loads on sources converter are also analysed using this.


10. Wind - battery hybrid system with maximum power point extraction for residential loads

Siddharth Joshi, Vivek Pandya and Bhavesh Bhalja

This paper proposes a hybrid wind (of 28 kW)generation system for standalone application with battery backup of 4.5 kW. This system is useful where grid connection is not viable and costly; particularly in the remote area. To enhance the performance of the proposed hybrid scheme, maximum power point tracking (MPPT) algorithm is implemented using DC-DC boost converter. The performance of the proposed system has been validated on an equivalent electrical load of the order of 17 kW using permutations and combinations of various types of residential load. Its performance has also been evaluated for extreme operating conditions of radiation levels, wind speeds and load switching events along with variation in climate conditions. The simulation results clearly indicate that the proposed hybrid wind battery satisfy the power demand and regulate the DC bus voltage as per IEEE 1250 standard.

11. Solar power forecasting techniques and metrics for accuracy of solar forecasting: a review

Chaturvedi D K, Isha Yadav and Vikas Pratap Singh

The increasing demand for energy is one of the biggest reasons behind the integration of solar energy into the electric grids or networks to ensure the efficient use of energy PV systems it becomes important to forecast information reliably. The accurate prediction of solar irradiance variation can enhance the quality of service This integration of solar energy and accurate prediction can help in better planning and distribution of energy Here in this paper, a deep review of methods which are used for solar irradiance forecasting is presented These methods help in selecting the appropriate forecast technique according to the needs or requirements. This paper also presents the metrics that are used for evaluating the performance of a forecast model.

12. Ice based energy storage integration with solar PV power plants for cooling energy

Siddhartha Bhatt M

This paper gives aspects of the design of Cooling Thermal Energy Storage (CTES) for cold storage refrigeration and building air conditioning plants, powered/integrated through Solar Photo Voltaic (SPV) power. Ice based CTES are useful when there is mismatch between the availability of the energy source (grid tied centralized system or roof top decentralized system) and the air conditioning/refrigeration application period. In both grid power with time of the day metering or SPV powered systems in integrated as well as in decentralized SPV, the source-load mismatch is handled through an ice storage system. The ice storage system not only helps with operation under decoupled source-load environment but gives the benefits of reduction in maximum output power, average power and energy consumption by 20-40 % as compared to conventional systems in centralized as well as decentralized environments.


13. Energy environment implication in thermal power plant by using supercritical technology – Indian scenario

Anil B Onkar, Dhomane G A, Moharil R M and Prashant P Mawle

In India, emissions of Green House Gases (GHGs) are increasing due to rise in energy demands to sustain economic growth. Coal is used as a dominant fuel in Indian thermal power plants but the efficiency of these is low in comparison with prevailing international standards. As such emissions of GHGs are much higher and feasible to achieve. The adoption of Clean Coal Technologies (CCTs) – like the Supercritical (SC) steam cycle – for new capacity addition in Indian thermal power plants will increase the efficiency of the Indian grid. These technologies are more environmentally and would help to meet increased energy demands. India has taken initiatives for the adoption of the technology as explained in the 11th plan of the Planning Commission. Finally, it is concluded from the study that SC and USC technology penetration would be helpful for reducing GHGs emission. The hypothetical scenarios analysis shows that up to 50% technology penetration for new capacity addition until 2027 would be helpful for reducing GHGs emission.

14. Numerical prediction of erosion in coal burner of 210 MW boiler through computational fluid dynamics modeling

Kumar R K, Raghavendra Naik, Saravanan V and Janardhana M

The splitter plates of coal burners in Indian thermal plants are subjected to severe erosion and erosion-corrosion conditions owing to the combined effect of abrasive nature of coal and elevated service temperature environment. During service, tilting of splitter plates is adopted to achieve the desired final steam outlet temperature which shifts the fireball location and heat release area in the combustion zone. The tilt condition gives rise to a change in the incidence angle of the coal particle as well as the change in flow profile. The erosion life of these plates is predominantly affected by the coal particle velocity, impact angle, particle size and steady state metal temperature during service. The sensitivity of burner tilt angle on the erosion life requires an understanding of primary air with coal particle flow phenomenon within the burners. The effect of burner tilt angle on the erosion of presently used SS310 grade splitter material was studied through computational fluid dynamics. The erosion sensitive velocity exponent was calculated based on the laboratory simulated erosion tests at elevated temperatures upto 700°C. The life of the splitter plates was calculated based on the predicted erosion rate intensity.


15. Root cause analysis of failure of 40th stage moving blade of single cylinder condensing turbine

Kumar R K, Janardhana M and Bhaskar Sharma K V

Blade failures in steam and gas turbines are quite a common occurrence. The last stages of steam turbines are designed to have the lowest possible fluid temperature. In view of the longest blade length in the last stages, the blades are subjected to highest bending moment forces and susceptible for erosion-corrosion phenomenon owing to the low service temperature environment. The failure analysis of last stage blade of 54 MW direct condensing type gas turbine are presented. The blade was made of martensitic grade stainless steel. Detailed analysis of the blade surface, lacing wire hole as well as the fracture morphology was analyzed using SEM-EDX. The probable reason for the failure of the blade was brought out based on the detailed investigations of the failed blade as well as the vibration signature analysis at the time of failure incidence.

16. Solid particle erosion of HVOF sprayed (35WC-Co/NiCrBSi) coating at higher temperature

Raghavendra Naik K, Kumar R K, Saravanan V and Shekhar Kumar M

High temperature erosion is generally encountered in boiler components in thermal power plants, especially in superheater, reheater, and economisers parts, where in fly ash particles attack the boiler components and cause high temperature erosion phenomena. It is known as fly ash erosion. The erosion behavior at elevated temperature is much different from that of room temperature erosion as there would be a higher erosion loss encountered at higher temperature due to higher plastic deformation as well as weak bonding between grains/particles. It is therefore imperative to study in depth the erosion wear assessment both at room temperature as well as at elevated temperature in the laboratory. This paper investigates thermal sprayed coatings produced by the high velocity oxygen fuel (HVOF) to improve the material performance under such conditions. 35 WC-NiCrBSi HVOF sprayed coatings were tested under high temperature (up to 700 oC) erosion by means of an apparatus that simulated real conditions. The results showed that under these tests conditions the 35WC-NiCrBSi coating worn about 1.4 times less than bare SS-310 steel at room temperature and 300o C Temperature, while at 700o C35WC-NiCrBSi worns about 2 times higher than bare SS-310 steel at 90o impact angle. This shows 35WC-NiCrBSi erosion sensitivity at higher temperature.


17. Failure analysis of high strength T91 boiler tubes used in thermal power plant: A case study

Arvind Kumar, Malabika Roy, Janardhana M and Shekhar Kumar M

A power generating utility of 600 MW has reported the failure of boiler tubes after a service life of 265 hours against the design life of 25-30 years. The failure of tubes was reported in Re-heater Inlet Coil tubes which were made up of high strength material alloy of SA 213 T91 grade. These boiler tubes were operating under a high temperature and pressure. The material used for re-heater and super-heater boiler tubes should have enough creep strength to sustain at high temperature and pressure. Even though T91 grade steel has superior quality of metallurgical properties in comparison to low alloy existing material like T11, T12 and T22, T91tube was failed in a short duration. This paper describesthe investigation of the failure of high strength T91 gradereheater tubes in a coal fired thermal power plant. The failure investigation covers visual inspection, dimensional measurement, hardness mapping, oxide scale measurement, microstructural studies, and SEM and EDX analysis of the failed tubes. The analysis reveals that Tube No-3 of re-heater boiler tube failed due to short term overheating and other tubes failed due to secondary damage caused by steam impingement.

18. Quantitative estimation of mullite in alumina based porcelain insulators samples

Vynatheya S, Suryanarayana K, Shekhar Kumar M, Santhosh Kumar B L, and Bheema Raju V

Although porcelain insulators in power lines have been in use for decades, several undergo catastrophic failures while early in service. A study addressing the materials aspects has been conducted on alumina based porcelain insulators. Apart from their electro mechanical stability characteristics, material aspects like composition, phase and microstructure play a very important role in their performance. The qualitative phase analyses on the insulator samples give an idea about the different major and minor phases present. Attempts have already been made to estimate α alumina and α quartz content in porcelain body. Mullite is another important phase present in the porcelain body, which gets formed during firing of raw materials during insulator manufacture and which has not been estimated quantitatively. An attempt has been made here to assess the mullite content in the alumina based insulator samples by X-Ray diffraction quantitative analysis. Internal standard method of quantification has been adopted successfully for the analysis. This article describes the quantification of mullite phase by the internal standard method based on X-Ray diffraction principle.


19. Microwave sintering: An energy efficient process for sintering aluminium metal powder

Ananda Kumar M G and Jagannath Nayak

Microwave sintering process is quite significant and unique in recent times for sintering material for densification because of its intrinsic advantages such as rapid heating rates, reduced processing times, uniform temperatures with minimal thermal gradients. Microwave sintering process leads to substantial energy savings with higher efficiency, improved properties, finer microstructures, environmental friendly process and with less environmental hazards. The concept of sintering metals in microwave has been attempted by many researcher. Though metals are known to reflect microwave radiation, researchers have confirmed sintering of metas in powder form through microwave. In this study, sintering of aluminium metal powder through microwave route has been attempted. The study indicated that aluminium metal powder compacts sintered through microwave process showed better physical, tribological and thermal properties compared to the ones sintered through conventional sintering methods.

20. A study on the mechanical behaviour of microwave sintered aluminium cenospheres based syntacticfoams

Ananda Kumar M G, Nataraj J R, Seetharamu S and Jagannath Nayak

Aluminium Syntactic Foams(ASF) are metallic foam material that are of great interest to the automobile manufacturers for their light weight coupled with tailorable engineering properties. Sufficient studies have been carried out on development of aluminium cenospheres based light weight syntactic foams which are fabricated through stir casting and melt infiltration techniques but it is seen from the literature that the synthesis of Aluminium Cenospheres metal foams fabricated through Powder Metallurgy (PM) route and densification through Microwave Sintering (MWS) has been less studied.

In this context, ASFs comprising of Aluminium metal matrix embedded with fly lsh cenospheres particulates have been fabricated through Powder Metallurgy (PM) route and sintered through Microwave (MW) sintering process at a temperature of 665° C. Cenospheres ranging from 0 to 50 volume%have been incorporated in the mix. The sintered ASF has been taken up for characterization for the mechanical properties such as Compression and Flexural strength. The compression test samples have also been taken up for Finite Elemental Analysis (FEA) and the Flexural Strength tested samples have been studied for fractography using scanning Electron Microscope (SEM). There sultso btained have been compared with aluminium cenospheres foamsthatwere sintered through conventional sintering process at the same temperature in electrical resistance furnace. Microwave sintered samples have shown better mechanical properties compared to the conventionally sinteredones. The study has been conducted to assess the suitability of using these ‘Syntactic Foams’ material for applications in automotives and other engineering applications.

The Journal of CPRI, Vol. 12, No. 3, September 2016

ABSTRACT LISTTHE JOURNAL OF CPRI - Vol. 12, No. 3, September 2016

1. Dynamic performance of distance relay for series compensated transmission lines using Real Time Digital Simulator (RTDSTM)

Boda Anilkumar*, Amruthakala A** and P S Puttaswamy***

Series capacitors are installed in the power system for various reasons like to increase power transfer capacity, to improve the system stability, to reduce system losses, to improve voltage regulation and flexible power flow control. But it also affects the performance of the conventional distance relay and causes certain protection issues. This paper briefly discusses the problems like voltage inversion, current inversion, overreach and under reach during the fault conditions on the series compensated lines and how the distance relays can mal-operate, by using RTDSTM. Before installing the relay in the actual system, it is possible to make compromised settings for relay, by understanding its performance due to the above problems and prevent relay to be mal-operated.

2. Synchrophasor-assisted detection and control of emergency voltage instability conditions

Imran Sharieff Md* and Ranjana Sodhi**

An impending voltage instability can often be avoided with a timely detection, followed by appropriate control actions. This paper proposes a complete scheme for the detection of impending voltage instability and subsequently, devising an emergency control action using synchrophasor measurements. The impending voltage instability is assessed using voltage and current phasor measurements, which can be obtained from the Phasor Measurement Units (PMUs). These measurements are exploited to find the maximum transferable power to a load bus, which, in turn, is used to deduce a Voltage Stability Monitor (Sy-VSM). The value of the proposed indicator gives the distance to voltage collapse. When the proposed Sy-VSM drops beyond a certain limit, a two-staged Load Shedding (LS) scheme is initiated as an emergency control action. Stage-1 sheds a fixed amount of load in multiple steps, taking into account the time, location and amount aspect of LS. In post-stabilization Stage-2, the amount of load curtailment is optimized using Model Predictive Control (MPC) based approach. The proposed scheme is demonstrated on the New England 39-bus system and a practical Indian Northern Regional Power Grid (NRPG) 246-bus system, and the results are found to be very encouraging.

3. Adaptive distance relay scheme for a DG based network using RTDSTM

Shashank Shekar M*, Amruthakala A**, Parthasarathy S S***and Prabhakar Karthikeyan S****

The power generated from Distributed Generations (DGs) such as wind and solar are eco-friendly and sustainable. Investigation on the impact of DGs on the power system network is presently a challenging task for the researchers. If the power generated from these energy sources are bulk and dispatchable then they are directly integrated into the transmission network. As transmission network is protected by distance relays, in-feed from DG will results in reach problems. This paper investigates on how the in-feed from DG source affects the operation of existing distance relays leading to over reach and under reach problems. The distance relay group settings are set in such a way that from the status of DG Breaker, the relay automatically switches to new settings which shows an adaptive approach, i.e., by communicating breaker status to the relay input contacts to make the relay adaptive based on the changes in the network topologies and to avoid maloperation of relay for effective protection, security of equipment and reliability of power transfer. This proposed adaptive scheme is implemented on a test transmission network simulated using Real Time Digital Simulator (RTDS) TM.


4. AnewapproachforplacementoffiringanglemodelofTCSCtoimprovetheperformance of transmission system

Hema Sekhar A* and Lakshmi Devi A**

For the efficient transmission of power from power plants to consumer loads, the power losses are reduced and voltage profiles are improved in modern power system. In order to reduce such losses and improve voltage levels , a recently evolved FACTS technology is used. In this paper, Thyristor Controlled Series Capacitor (TCSC) is selected to enhance the load ability in the transmission line. This paper presents a new approach on modeling of the device by changing the firing angle of the power electronic device of the FACTS device. This is done by using Hybrid GA-PSO and DA-PSO which is participated to finalize the best location of the TCSC device and optimal firing angle of the TCSC. The location of the device is optimized by either GA or DA and the optimized firing angle is done with PSO algorithm. Because of the two different Optimizing techniques are used to solve single objective function. This type of optimization is called Hybrid optimization. The proposed hybrid optimization method is an effective method for finding the optimal location of TCSC device and also for enhancing the voltage profiles of the line and reducing the power system losses. This hybrid GA-PSO and DA-PSO is tested on IEEE 57 test system and simulation results are presented.

5. Performance evaluation of G3-PLC over distribution transformers in Indian context

Konark Sharma* and Lalit Mohan Saini*

The past few years have witnessed a tremendous development in Power-Line Communications (PLC) technology such as G3-PLC with existing power-lines for high speed data communication across High voltage (HV), Medium Voltage (MV) and Low Voltage (LV) transmission/distribution networks based Smart Grid (SG) applications. As power-lines were not originally intended for conveying high frequency signals, and any communication over these lines would be exposed to severe adversarial factors, such as interference, impulsive and phase noise. G3-PLC technology also elucidates the importance of employing robust modulation schemes across distribution-transformers and motivates research in this direction. Indeed, the aim of the paper is to investigate G3-PLC channel measurements through MV/LV distribution-transformers by implementing experimental tests to analyse the signal-to-noise ratio (SNR), Bit Error Rate (BER) and Packet Error Rate (PER) performance of DBPSK, DQPSK and ROBO (Robust) modulation schemes over multipath PLC channels in Indian context.

6. Performance evaluation of distribution network - power quality approachSurendra Kalambe*

In the modern era power quality has become a serious issue due to ever increase in use of Non linear loads i.e. variable speed drives, power electronics gadgets etc. The IEEE 519 guidelines deliberates the concept of powering equipment in a manner that is suitable to the operation of that equipment. This paper explains details of quality of power supplied and handled by the equipments at the distribution substation, to know the status of the substation equipment; which are mainly responsible for the power quality, The reality check of substation losses and the compatibility of distribution network with standard of performance for reliability improvement of electrical system and network. Means adopted for loss reduction, Overview of various power quality parameters. The best possible solutions to the power quality problems are discussed and their practicable functioning is discussed. The solutions present in the field are explained and field results are presented. Emphasis has been given to explain that by using proper technology a various power quality problems can be addressed.


7. MaximumannualsavingsinradialdistributionsystemsusingfireflyalgorithmDinakara Prasad Reddy P* and Chandra Sekhar B**

This paper presents a two stage approach that determines the optimal location and size of capacitors on radial distribution systems to improve voltage profile and to reduce the active power loss. In first stage, the capacitor locations can be found by using loss sensitivity method. Firefly algorithm is used for finding the optimal capacitor sizes in radial distribution systems. The sizes of the capacitors corresponding to maximum annual savings are determined by considering the cost of the capacitors. The proposed method is tested on 15-bus and 34-bus test systems and the results are presented.

8. Technological development of on - load tap changing mechanism in power trans-former - a review

Savita V Banakar*, Muralidhara V** and Maheswara Rao N**

Voltage control is one of the main concerns of power utilities with regard to quality of the power. To maintain load voltage within permissible limits every power transformer is designed with voltage controlling and regulating system. Hence transformers are required to supply with an On-Load Tap Changer (OLTC) which became mandatory. The OLTC voltage regulation is naturally operated by Changing the number of turns in one of the windings of the transformer. This paper presents a review of a differentiated details of conventional mechanical OLTC and electronic assisted tap changer as controller.

9. Intelligentcontrolofshuntactivefilterforpowerqualityimprovement using fuzzy logic

Arunesh Kumar Singh*, Talish Naseem** and Vikas Pratap Singh***

Now a days, power quality issues are very important for the sensitive equipments to increase the efficiency of the syatem. In the power system, disturbances are due to non linear characteristics and fast switching of the power electronics apparatus. Because of the use of the power electronic devices many distortions are introduced. Due to these harmonics the devies connected to the system suffer and their life is reduced. Our main aim is to use a shunt active filter that improves these harmonics and gives a sinusoidal current at the load side. For improving power quality fuzzy controllers are used and found to be better than traditional controllers.

10. Simulation and implementation of phase shifted series resonant converterJayandiran S*, Karpagam R** and Elanchezhian P***

This paper deals with digital simulation of phase shifted series resonant DC to DC converter using Matlab SimulinkTM. The simulink models for open loop and closed loop systems are developed and they are used for simulation studies. Normally single voltage feedback is required for the system. This system consists of two control loops with one inner resonant vector and one outer voltage loop. The dynamic response improved by this dual loop method. This converter is capable of producing ripple free DC output. Switching losses and switching stresses are reduced by using soft switching. This converter has advantages like high power density and low switching losses. Theoretical predictions are well supported by the simulation results.


11. Micro controller programming for PWM control of MOSFET based convertersVani Vijay*, Giridhar Kini P** and Sudhir Kumar R*

Pulse Width Modulation (PWM) control of MOSFET based converters is used in almost all electrical application for accurate and efficient operation, like in motor drives, power supply units, power conditioners etc. The algorithm of PWM control in such system is the most important factor determining the operational features which can be implemented using microprocessors, micro controller, digital signal processors or higher end technologies. Here a detailed study of micro controller programming is done for PWM control of MOSFET based converters. The method of configuring the controller for PWM generation and programming steps are explained in detail with an example of PIC16F877A micro controller. Hardware implementation is done and program variation for different operating characteristics are observed. Micro controller programming is easiest, accurate and cost effective method for PWM control of converter. The program is flexible and higher end micro controllers can be used for complex control technique.

12. Design and development of type-B pulse forming network for generation of low voltage rectangular pulses

Madhu Palati*

Rectangular pulses of short duration find more importance in applications like charged particle accelerators, microwave sources, Lasers and microbial deactivation in food. Rectangular pulses of short duration in the order of few microseconds are generated commonly by using pulse forming networks. In the present work, a low voltage, type-B Pulse Forming Network (PFN) for generating rectangular pulses of duration 1.8 µs is designed, and developed. Simulation is carried out in PSPICETM and the effect of first and last stage inductances on the overshoot of the output waveform is studied. The characteristic impedance of the type-B PFN is 10 Ω. Load impedance is chosen as 10 Ω to discharge maximum energy of the generated pulses effectively into the load circuit. A low voltage rectangular pulse of output voltage of 560 V and duration 1.6 µs is achieved experimentally.

13. Analysis of short circuit faults in DFIG and PMSG wind farmsShripad G Desai*, D S Bankar**and Vishal V Mehtre***

Transients in power system pose severe threat to the operation and control mechanism. various abnormal conditions categorized under short circuit faults have adverse effects on the system operation. Short circuit faults namely a single L-G fault and 3-Φ short circuit faults are to be given major importance to ensure reliability of the overall system. It is well known that these short circuit faults rather symmetrical or unsymmetrical are to be cleared as soon as possible. The clearing time of these fault currents is of major importance and emphasis has to be given on generator types which are capable of clearing such faults in a quick time. The paper focuses on two concerned generator’s mainly used in the wind energy sector namely a DFIG type and the PMSG. Both these WTG (Wind Turbine Generator) topology are analysed for their short circuit capability in terms of impact of short circuit faults, time for recovery after occurrence of short circuit fault and for system oscillations if any.

14. Fault ride-through capability of permanent magnet synchronous generator based wind energy conversion system

Rajvikram M*, Renuga P**, Aravind Kumar G*** and Bavithra K****

In order to minimize the environmental pollution and to meet the demand of power generation, the electrical power is generated through the renewable energy resources. The wind energy is the massive energy resource compared to other mode of renewable energy resources. This paper deals on the fault ride-through capability of Permanent Magnet Synchronous Generator (PMSG) wind turbines. The main


attention in the paper is, to control the PMSG wind turbine and its power converter and to the ability to protect itself without disconnection during grid fault is the main work focused in this project. Also this paper provides the necessary information on the interaction between variable-speed PMSG wind turbines and the power system subjected to faults, such as short circuit faults. The PMSG based WECS is subjected to the grid faults it will cause the oscillations in the DC link voltage at back to back converter. A crowbar and Super Conducting Fault Current limiters (SCFCL) is proposed to supress the DC link voltage oscillations and to enhance the Low Voltage Ride-through (LVRT) Capability of PMSG based wind turbine. To achieve the reactive power support at the grid side the STATCOM is implemented. The simulation results implemented in Matlab/Simulink show that the proposed control strategy not only improves the stability of PMSG by means of suppressing the DC-link voltage oscillation, but also provides a transient stability support to restraint the disturbance of the grid voltage.

15. Off-grid electrical power generation and environmental impact with renewable energy in India

Bharat Modi* and Umesh Kumar Rathod**

India is developing country and electricity demand is increase day by day. Many of Indian villages about 18000 are not electrified since independence. Deen Dayal Upadhyaya Gram Jyoti Yojana (DDUGJY) is a government of India scheme designed to provide continuous power supply to off-grid rural India. The purpose of this paper is to propose the best hybrid technology combination for off-grid electrification of rural area where conventional grid power supply is not possible. Electricity need for an off-grid remote area supply from a mixture of biodiesel generator, small hydro plant and renewable energy resources to satisfy in a reliable manner. Here we are using HOMERTM (Hybrid Optimization of Multiple Energy Resources) software is used for whole analysis. The simulation results indicate that the proposed hybrid system would be a feasible solution for distributed generation of electric power for remote locations compare to conventional grid extension.

16. Modeling of hybrid ultra-capacitors for power electronic applications using PSPICE/ORCAD™

Pradeep Kumar Rao J* and Nagamani H N**

Hybrid ultra-capacitors are the integration of super capacitor and battery technologies. For performance improvement of a hybrid capacitor based system, accurate modeling is one of the requirements. Hybrid ultra-capacitor or Hybrid Capacitor (HUC) is modeled and then simulated from fundamental circuit of super capacitor with focus on leakage resistance parameter variation. Super Capacitor (SC) - MAXWELLTM 100F is simulated in its 5th order and simplified to 2nd order maintaining charge sustenance. All the simulations are performed for the first time in PSPICE/ORCADTM. The paper focuses on charging/ discharging capability of the model in time domain, such that the properties of high energy density, high power density and cycle life of the hybrid capacitors retain.

17. Single-ended resonant inverter for photovoltaic applicationsElanchezhian P* and Kumar Chinnaiyan V**

The Single-Ended (SE) resonant microinverter is a type of class E parallel resonant inverter and popularly used in many applications due to its lower cost structure and relatively high efficiency. However, its maximum power rating should be limited because the resonant voltage of SE resonant inverter increases as its power increases. Consequently, the maximum power rating of SE resonant inverter should be limited up to around 2 kW. This paper proposes an interleaved single-ended resonant inverter for the photovoltaic applications. The proposed inverter can provide two times higher output power than the conventional single-ended resonant inverter. A burst mode control enhances the power control range from very light load to full load and can improve efficiency.


18. Integration of concentrating solar power in cane-based sugar cogenerating plants- a strategic energy option for India

Siddhartha Bhatt M*

The presently tapped potential for cogeneration from sugar plants in Indiain India is very low (4.8 GW). There is the good untapped potential of around 10 GW from the sugar sector besides opportunities for enhancing the annual plant load factor (PLF) during the off-season phase. The use of Concentrating Solar Thermal power (CST) in the Indian power sector is gaining importance since 2014 as the linear parabolic trough technology is now available. A number of plants based on CST have been established in Rajasthan and Tamil Nadu. In this paper, the integration of CST plants with sugar based cogeneration plants (where the PLF is limited by the availability of bagasse) is presented in view of the great strategic importance of this combination which does not need the power block for CST and enhances the capacity utilization of sugar mills. By the introduction of CST, during the crushing seasons there is saving in bagasse and during the offseason, generation is ensured. On the overall, by the use of CST, the annual PLF can be increased from 69 % to 77 %.

19. New concept for steam condensation Mallikharjuna Rao T* and Rao S S**

This paper explores the feasibility of using the heat pipe for steam condensation. In this paper an attemptis made to replace thousands of condenser tubes by hundreds of heat pipes.The design details of heat pipe like material, length, diameter etc., are described in this paper. The feasibility study was carried out for smooth operation of the heat pipe that is without ceasing during operation. Experimental setup and results of steam condensation are presented.

20. Characteristics of different Indonesian coals blended with a high ash Indian coalArun Kumar K H*, Saravanan V** and Shekhar Kumar M***

Two Indonesian coals from different mines were blended with a high ash representative Indian coal obtained from South Eastern Coalfield Limited (SECL) mines at different proportions like 10/90, 20/80, 30/70 and 50/50. These blends were characterized for the qualitative and quantitative parameters based on additive rule. The additive/non-additive behavior of these blend proportions were studied comparing the experimentally obtained value with the calculated values based on additive rule. The results obtained indicate that the quantitative parameters like proximate and ultimate parameters were found to be additive and the qualitative parameters like ash fusion temperature and Hardgrove Grindability Index (HGI) were found to have deviation from the calculated values. Among the two different blends one blend showed additive characteristics on the HGI values while the other one showed non-additive characteristics. The Ash Fusion Temperature (AFT) was found to be non-additive in both the blends.

21. A study on the slagging and fouling propensity of imported coals blended with Indian coal

Ananda Kumar M G* and Saravanan V**

Coal blending excercises are becoming popular in the present day scenario with many of the Indian thermal power plants. Blending of an inferior variety of indigeneous coal with that of high quality imported coal is gaining importance. With the depleting coal reserves in the country leading to deterioration of the indigeneous coal quality and less availability of the high grade coals, it has become imperative on part of the power generation plants to import high quality coals and blend them with inferior variety of indigeneous coal and burn them in the boilers for power generation.


It is challenging to ensure that the resulting coal blend will maintain the required plant output without damaging the boiler and high temperature components.

Combustion of various coalsblends in the boiler lead to a variety of complex thermochemical reactions. The inert residue of coal combustion product which is ash is composed of complex oxides of various minerals. The quantity and the characteristic of the ash is inherent to the particular type of coal combusted. The fusion of this ash in the boiler during combustion may sometime lead to slag forming and fouling problems. This slagging and fouling phenomenon is dependent on a number of factors such as the ash chemical composition, combustion temperature, combustion atmosphere, boiler operating parameters etc., Deposition of coal ash/slag and fouling impedes the heat transfer there by increasing the Flue Gas Exit Temperature (FEGT). Ash deposits due to fouling on convective pass tube banks can block flow passages. Large deposits in the upper furnace or radiant zone dislodge and fall which may cause damages to the lower furnace pressure parts. Extreme ash deposition leads to forced outages and corrosion problems. Keeping the above in view it is important to study the various parameters related with blended coal so as to ascertain the proper blend ratios, operating temperature, boiler conditions and other factors.

In this study 3 types of imported coals and an Indian coal was blended in various proportions and the blended coals were studied for their various paratmeters such as ash fusion temperatures, chemical compositions etc., and by applying certain indices, the behavior of the residual blended coalash for its slagging and fouling propensity have been reported.

22. High temperature erosion resistance characteristics of boiler tube materials of thermal power plant

Kumar R K*, Raghavendra Naik K** Janardhana M *and Kiran K B ***

The boiler tubes of Indian thermal power plants are exposed to severe erosive ash environment leading to continuous metal wastage and failure. The erosion resistance of the boiler tube material is affected by hardness, particle velocity, impact angle, particle size and metal temperature. The parameters affecting the erosion resistance properties are required to be evaluated in the laboratory under accelerated condition using a tunnel type erosion test rig. The present paper highlights the results of high temperature erosion of five different widely used boiler tube materials such as T11, T91, T22, carbon steel, and SS304 have been brought out in terms of their erosion resistance properties under different temperature conditions. The properties are compared with that of room temperature erosion resistance properties. The erosion resistance characteristics were studied for different velocity and impact angles around the circumference of the boiler tube. The evolution of surface roughness corresponding to different angles around the boiler tube, upon erosion, in comparison with the carbon steel tube, is presented.

23. Condition assessment of generator rotor shaft of 108 MW hydro plant through phased array ultrasonic technique and estimation of remaining life through finiteelementanalysisKumar R K*, Janardhana M*, Venkatesh T R*, Shekhar Kumar M* and Arun Kumar K H**

The Condition Assessment of Generator rotor shaft of typical 108MW plant has been carried out involving the application of advanced Phased Array Ultrasonic Technique (PAUT)to quantify the volumetric nature of the defects in the rotor. This technique involves mapping of the entire rotor volume in different segments and layers using multiple ultrasonic sensors. The imaging of defects in the rotor shaft was carried out in four different diameter sections 558 mm, 610mm, 737 mm and 914 mm. The scanning of entire shaft geometry regions was done following different patches from top to bottom portion of the shaft by PAUT and analysis of individual scanning results for evaluation of crack size, position inside the rotor geometry and orientation. The critical defects identified by this technique with


their locations and orientation inside the rotor has been presented. The stress and fatigue life of the shaft under defect free conditions have been carried out by finite element analysis using the commercial code Fe-SafeTM. The calculation of remaining life of the rotor shaft was carried out based on the principle of fracture mechanics using the code ZENCRACKTM. The results of the crack growth rate data of critical cracks close to the surface were presented.

24. CFD modelling of the blended coal combustion in a typical 210MW Indian boiler

Arun Kumar K H*, Saravanan V**, Kumar R K** and Shekhar Kumar M***

The computational fluid dynamics (CFD) assessment was carried out for the combustion of pure Indian coal and the blends of Indian/imported coals at various proportions in a typical 210 M We Indian boiler. The input fuel mass flow rate was calculated in various cases to give the same thermal input to the boiler. The various sub models used for the CFD assessment has been described in the paper. The velocity and temperature profiles of the gas phase, combustion profile of the particles, heat flux distribution to the walls of the boiler and also the thermal efficiency of the boiler were assessed in the present work. It was found that the particle and fluid dynamics play a major role in the heat flux distribution in the boiler. The Indian and imported coal blend proportion of 80/20 showed good thermal efficiency compared to the pure Indian coal and other blend proportions.


ABSTRACT LISTTHE JOURNAL OF CPRI - Vol. 12, No. 4, December 2016

1. Implementations of Sweep Algorithm For Load Flow Analysis in Radial Distribution Networks

Kalidas Babu G * and Rajesh Kumar Samala**

Power system is the most complex man made inter connected system with the combination of power generation, transmission and distribution to the consumer loads. In order to determine the behavior of the entire system i.e., planning and design, economic operation, stability. etc of the power system the power flow or load studies plays vital role. By using this power flow solution we obtain magnitude and phase angle of voltage at each bus, real and reactive power flowing through the branches by using conventional iterative techniques like Gauss-seidal, Newton Raphson method, Fast decoupled methods. This paper gives the complete load flow analysis of a radial distribution network with a proposed simple backward/forward sweep algorithm method which gives better convergence and takes full advantage of the radial structure of distribution systems tested for the IEEE 33 bus and IEEE 69 bus system implemented in MATLABTM code.

2. Application of Ant Colony Optimization Algorithm for Voltage profile Improve-ment

Rayudu K *, Yesuratnam G** and Jayalaxmi A***

Minimization of voltage deviations and power loss can be controlled by Optimal Reactive power Dispatch (ORPD) for voltage stability of the system. This paper presents a real ant colonies foraging behavior procedure for solving the ORPD problem using Ant Colony Optimization (ACO) algorithm. The objective of this paper is to minimize the voltage deviations at load buses using control and dependent variable constraints with proposed sensitivity parameters of reactive power. The On-Load Tap Changing Transformers (OLTC), Generator Exciters, Switchable VAR sources are used as control variables for improvement of system parameters like Voltage deviations, L-index and Power loss. The effectiveness of the proposed method is demonstrated on New England 39-bus system for near optimal solutions. The performance of the proposed method is compared with conventional optimization technique and presented for illustration purpose.

3. Non Intrusive Monitoring of Electrical Cables in Ship Power Systems Shashidhar Kasthala* and Rajitha Saka**

The integrity of power cables is vital for the reliability and safety of an electrical system. The change in operating conditions of the electrical cable often leads to unanticipated faults or premature ageing and any such defects has to be monitored so that corrective measures can be taken within the time. This paper discusses about a non-intrusive power line quality monitoring technique that can be used on ships to detect the faults based on the Power Line Communication (PLC) technology. The relationship between the channel frequency response and the power line quality features are studied and any changes in the positions and values of peaks or valleys and distance between peaks or valleys are monitored.

The Journal of CPRI, Vol. 12, No.4, December 2016

4. Enhancement of ATC Using Series Compensation In Restructured Power System

Laxmi Niveditha*, Krishna Reddy Ch.V* and Venkata Prasad P*

This paper presents enhancement of the Available Transfer Capability (ATC) using series compensation. It is imperative as part of the nature of the restructured power system to supply reliable and economical power supply. Owing to the expanded nature of the power system and large scale power transactions, it is important to determine ATC in a fast and accurate manner. At the same it is required that the transmission lines be utilised in the most optimum manner and hence requires the enhancement of ATC. The DC-PTDF method is used in this paper to calculate ATC under both intact condition and line outage contingency condition. Further series compensation in done in the transmission lines to enhance the ATC in both the cases. The proposed method is presented using IEEE-6 bus system.

5. An Improved IUPQC with Fuzzy Controller Providing Grid Voltage Regulation as a StAtCOM

Rajeshwari V R* and Suresh Kumar B**

Abstract: This paper presents using fuzzy logic an improved controller for the dual topology of the Unified Power Quality Conditioner (iUPQC) extending its applicability in power-quality compensation, as well as in microgrid applications. Beyond the conventional UPQC power quality features, including voltage sag/swell compensation, the iUPQC will also provide reactive power support to regulate not only the load-bus voltage but also the voltage at the grid-side bus by using this controller. The iUPQC will work as a Static Synchronous Compensator (STATCOM) at the grid side, while providing also the conventional UPQC compensations at the load or microgrid side by using fuzzy. simulation results are provided to verify the new functionality of the equipment.

6. Investigation of UPQC for Power Quality Distortions in DFIG based Wind Farms

Mastanamma Y*and Bhoj Reddy**

This paper presents a new Synchronous-Reference Frame (SRF)-based control method to compensate Power-Quality (PQ) problems through a three-phase four-wire Unified PQ Conditioner (UPQC) under unbalanced and distorted load conditions for DFIG based wind farm. The proposed UPQC system can improve the power quality at the point of common coupling on power distribution systems under unbalanced and distorted load conditions. The simulation results based on Matlab/Simulink are discussed in detail to support the SRF-based control method presented in this paper.

7. An FPGA Based Single Phase Multilevel InverterSasi Kumar G*, Sourav Bhalotia** and Harish Pappu***

This work presents a new multilevel inverter topology using an H-bridge with bidirectional auxiliary switch, eight diodes and two capacitors to get five level ac output. It presents an FPGA based gate signal generator for multilevel inverter to control its output voltage. The XILINX FPGA based multilevel inverter is chosen for the hardware implementation of switching strategy mainly due to its high computation speed that can ensure the accuracy of the instants that gating signals are generated. Spartan 6 board is used to get hardware output and these results are validated with simulated results


8. A Simplified SVPWM Control for Five Level Asymmetrical Dual Inverter Fed Induction Motor Drive

Usha N*, Venkata Prasad P** and Ramesh Reddy K***

Many of the Adjustable speed drives are inverter based motor drives. There are various PWM techniques to control the inverter. This paper presents modified control strategy for five level asymmetrical dual inverter fed induction motor drive. The control method for the inverter improves the performance of the drive. The characteristics of the drive at different modulation indices were observed and found that at higher modulation index the total harmonic distortion of line currents is less. The time response of speed is better at modulation index greater than 0.75.The simulation based analysis and design is carried out in MATLABTM software.

9. Design of three-Zone Hybrid Pulse Width Modulation Method For Reduced Current Ripple

Saketh Kumar B*, Abhiram T** and Sumanth K***

This paper presents a Three-Zone Hybrid Pulse Width Modulation (HPWM) algorithm for induction motor drives. This paper brings out a method for designing hybrid PWM techniques inVolving multiple sequences to reduce line current ripple. The three proposed hybrid PWM techniques (three-zone PWM) employ three different sequences, respectively, in every sector. Then, the rms stator flux ripple, which is a measure of ripple in line current characteristics have been plotted for all the HPWM and SVPWM algorithms. From which, it is concluded that the SVPWM algorithm gives superior performance at low modulation indices, whereas the HPWM algorithm gives superior performance at higher modulation indices. The proposed techniques lead to a significant reduction in THD over CSVPWM at high line Voltages. A Novel hybrid PWM technique, employing these two sequences in conjunction with the conventional sequence, is proposed. The proposed PWM technique is designed using the Notion of stator flux ripple. A procedure is presented for designing hybrid PWM techniques inVolving multiple sequences for reduced current ripple. The proposed PWM technique results in reduced current ripple over CSVPWM at higher modulation indices. The three-zone technique results in the lowest THD among real-time techniques with uniform sampling. Hence, to achieve the superior waveform quality at all modulation indices, a three-zone Hybrid PWM (HPWM) algorithm has been presented in this paper. To validate the proposed algorithms, several numerical simulation studies have been carried out and results have been presented and compared.

10. A Comparative Analysis on Different Control techniques for Buck ConvertersKrishnapriya* and Shashidhar Kasthala**

Buck converters are basically step down DC-DC converter which converts high DC input voltage to low DC output voltage. These buck converters are used extensively in industry and in research. One of the basic disadvantages of buck converters is the unregulated supply of voltage and current. To solve this problem various control techniques are used in combination with buck converters. In this paper some of these control techniques are compared summarized. Some of the famous control methods are Voltage Mode Control (VMC), Current Mode Control (CMC), PID control and Pulse width Modulation (PWM) control.


11. Performance Analysis of DVR and DStAtCOM in Distribution network for Voltage Sag and Swell Conditions

Thirupathaiah M, Venkata Prasad P and Ganesh V

Due to the increase in sensitive loads to power disturbances, power quality issues became one of the major concerns in many of the distribution systems and industries. The majority of events causing the power quality issues are because of voltage sag and voltage swell. In a distribution system, it is very important that the fault should be removed immediately so that the whole system is protected and the service is not interrupted. In this paper, the performance of Dynamic Voltage Restorer (DVR) and Distribution Static Compensator (DSTATCOM) is analysed by simulated with PWM control scheme using PSCAD. The simulations were carried out with various test cases associated with voltage sag and swell due to three phase short circuit fault, inductive and capacitive load switching conditions. The analysis of DVR and DSTATCOM was done based on the compensation of each device for various power quality problems. Results are presented for DVR and DSTATCOM showing the compensation of voltage sag/swell for various test conditions.

12. Need for Real Time Simulation in cyber security Applications Sreedevi J*, Noorcheshma P**, Ashwin N**and Meera K S***

Various sophisticated technologies have been deployed in the modern power system to facilitate the notion of smart grid, integrating the power system, associated IT infrastructure and the communication network into a Cyber-Physical System (CPS). The increasing coupling between a physical power system and its communication network necessitates a Cyber-Physical test environment to investigate and guarantee the grid’s stability and reliability. A Cyber-Physical Testbed consists of four components – a Physical power systems layer, a power systems monitoring layer, a Communication Network layer and an Energy Management Systems layer. In this paper, the need of a Cyber Security testbed is detailed along with an architecture of a typical Cyber Security Testbed and the role of a Real Time Simulator in the Testbed.

13. Grid Interactive Photovoltaic-Fuel Cell based Hybrid Generation System with Active and Reactive Power Control

Nilesh Shah* and Chudamani R**

In this paper, Photovoltaic (PV)-Fuel cell (FC) based grid interactive hybrid generation system is presented. The power generated by a PV system is highly dependent on weather condition. Hence, Fuel cell is used as back up source to supply the load demand along with PV under varying weather conditions. The PV-FC based hybrid generation system is developed using the model equations of PV and FC in the MATLAB/Simulink® environment. The PV-FC hybrid generation system is integrated with grid in two stages: dc-dc boost converter and three phase dc-ac inverter. Two separate dc-dc boost converters are used each with PV and FC system. In PV system, the dc-dc converter is used for Maximum Power Point (MPP) tracking and in FC system, the dc-dc converter is used for boosting the FC voltage. The MPP is tracked using fuzzy logic based controller under varying weather conditions. The power management algorithm proposed in this paper extracts and utilizes the maximum available power from PV array to supply the load demand. The FC is used to supply additional load demand higher than the maximum available PV power. The inverter injects the PV and FC power to load/grid in a controlled manner. The reference currents for current controller are generated using instantaneous power (p-q) theory. The hybrid generation system is tested under different load and weather conditions. The simulation results validate proposed power management algorithm for PV-FC based grid interactive hybrid generation system under varying environmental and load conditions.


14. Damping of Oscillations in Series Compensated Power System through Wide Area Damping Controller of StAtCOM

Vipin Jain* and Narendra Kumar**

In FACTS devices auxiliary signals are widely used to enhance damping and mitigation of Subsynchronous Resonance in Power System. Choice of auxiliary signal is indeed a difficult choice. Auxiliary signal may be local signal or remote signal. In this paper STATCOM is installed in the middle of Power system and it is shown that deviation in speed of generator rotor is one of the most suitable auxiliary signal. This signal is a remote signal hence a suitable time delay is considered. Study system is IEEE first benchmark model. Modeling of STATCOM with IEEE first benchmark model is presented in detail. All the differential equations and initial conditions are presented in the paper. Both, small signal and large signal stabilities are carried out.

15. Protection Algorithm for Photovoltaic Based Distribution System Tejeswini M V*, Sujatha B C** and Manohar Singh ***

Distributed Energy Resources (DERs) are small size power generating sources installed to electricity requirement of small scale electricity customers. Zero emission and renewable feature make them as popular choice for future energy demand particularly in peak demand in public utility network. The design of a protection scheme for their safe operation during utility tied connection and islanded mode of operation is an essential operational requirement. As the density of the photovoltaic based distributed energy resources increase in the distribution systems, the fault current contribution from these resources becomes comparable with the fault current from utility substation. Additionally the fault infeed for PV system is close to their loading limits and this possesses a great challenge for design of protection schemes. In this research article, a voltage and current based protection algorithm is presented which can accurately discriminate between the fault currents seen during utility tied and islanded mode of operation. The proposed algorithm is implemented in IEEE 9 bus reference network.

16. A Simple and General method to Perform Large-Scale Series/Parallel Reduction of Proximally Coupled two-terminal Networks by Employment of the Primitive Impedance/Admittance Matrices

Rao I R* and Shubhanga K N**

The process of reduction of series/parallel combinations involving an arbitrarily large number of magnetically coupled two-terminal networks containing a diverse combination of circuit elements is a conceptually fundamental task and yet has received only scant attention in relevant literature, the only attempts in this direction being limited to a few ad hoc and laboured developments featuring extremely elementary topologies while furnishing meagre, if any, scope for mathematical extension. This paper proposes a powerful tool wherewith large-scale series/parallel reductions of networks with proximal coupling may be achieved in an efficient and facile manner, without any specific limit on the number of constituents, thereby ensuring the generality of the approach. The primitive impedance/admittance matrices are employed for this purpose in their time-domain operational form, which ensures the retention of the most general form of the interrelationships between the terminal voltages and currents of the individual blocks as well as their combination. The presented method has been demonstrated with numerous examples involving inductor networks and inductor-resistor combinations in series, parallel,and some series/parallel topologies.


17. Optimization of torque and Flux ripple for DtC fed Asynchronous Motor Drive Using Hybrid Computing techniques

Chandra Sekhar J N* and Marutheswar G V**

Abstract- This paper presents a comparative study of Space Vector Modulation (SVM)-Direct Torque Control (DTC) of three-phase Induction Motor using conventional PI controller and Hybrid Computing Techniques like Genetic Algorithm tuned PI and Fuzzy Controllers. A dynamic modular model for the three-phase Induction Motor based on Krause’s model is developed and the required supply for this system is provided by a Space Vector PWM based three-phase Voltage Source Inverter. The main characteristics of DTC scheme applied to three phase Induction Motor is studied by simulation, emphasizing its advantages and disadvantages for different configurable controllers.Validation of the proposed system is verified and analysed using MATLAB/SIMULINK tool.

18. Experimental implementation of 100 W Photovoltaic Panel with DC-DC Boost Converter for Maximum Power Point tracking

Hareesh M*, Amarnath C** , Siva Kumar G*** and Sreenivasarao D****

The performance of a photovoltaic (PV) module is affected by irradiance and temperature. Often, it is also affected by partially or completely shaded conditions by passing clouds. This paper presents a MATLAB/SimulinkTM based model to study the I–V and P–V characteristics of a PV panel under partially shaded and non-shaded conditions. And also, Maximum Power Point Tracking (MPPT) of PV module by DC-DC boost converter is explained. The design of boost converter parameters and its affect on power tracking of the PV module are explained. The perturbation and observation (P&O) method is implemented for maximum power extracting from PV panel, because of its easy implementation. The P&O algorithm tune the dc-dc boost converter duty cycle to ensure that PV system operates at MPPT. A 100 W Photovoltaic (PV) panel with dc-dc boost converter is implemented practically for experimental validation. This work is extended for tracking of MPPT during shading conditions also. The P and O algorithm is implemented in DSpace, in which the output power of PV panel compared for every sampled time by varying the duty cycle in small steps.

19. Comprehensive Study of Static Voltage Stability Methods for Proper Placement and Sizing of StAtCOM to Enhance Voltage Stability

Telang A S* and Bedekar P P**

Voltage stability assessment and its enhancement have become the important aspects for modern power system operation and control. Static and dynamic are the two most important methods, to analyze the voltage stability. This paper presents a comprehensive study of almost all static voltage stability analysis methods such as PV-QV curve, Modal analysis, Load flow based voltage stability indices and continuation power flow method, for enhancement of voltage stability. Implementation of FACTS device like STATCOM, in the system, which is having fast and very flexible control, to achieve the maximum enhancement of loading margin in the power system is also presented. This enables one to identify the system’s critical area and to develop systematic approach for proper placement and sizing of STATCOM in the power system network.

The main contribution of this paper is identification of weak buses of power system using static voltage stability analysis methods and deciding proper location and size of STATCOM for voltage stability enhancement, under a novel load increase scenario i.e. active and reactive loads have been changed simultaneously at all the load buses under consideration. The study has been carried on various standard IEEE test systems using MATLAB programming as well user friendly Power System Analysis Toolbox


(PSAT) of MATLAB. The results of standard IEEE14 and IEEE6 bus test systems have been presented in this paper.

20. Analysis of VSC-HVDC system feeding a passive networkPrabhakar C* and Prasanna T S**

With the advent of Thyristor technologies, High Voltage Direct Current (HVDC) transmission system is used for transmitting large amount of power over long distance. It is a mature technology and has been playing a vital role in both long distance transmission and in the asynchronous interconnections. VSC-HVDC systems represent recent technology in the area of DC power transmission. One of the limitations in using conventional HVDC system is that it is difficult to connect to a weak network with no local generations nearby. VSCs are based on IGBTs that can be switched on and off by control signals and can be operated at high frequencies. Since VSC, has the capability to control both active and reactive power, it has become a widespread applications in power system. In this paper, the behavior of a VSC-HVDC system when connected to a passive network is studied under the steady state and transient conditions. The simulations are carried out using Real Time Digital Simulator (RTDS) available at CPRI, Bangalore. Simulation results proved that the modeled controller has good steady state and transient response during the faults. Performance of VSC-HVDC is also studied when feeding the loads like motors and found that the system response is satisfactory.

vol. 1. no. 1, sep 2004-abstract - central power research ... no-4_abstract-full_27-07-2017.pdf ·...

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