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CONTENTS

CHAPTER TITLE PAGE NOS

ABSTRACT

LIST OF FIGURES

LIST OF TABLES

I INTRODUCTION 1

1.1 LOAD FLOW 1

1.2 IMPORTANCE OF LOAD FLOW 3

1.3 DISBUT SOFTWARE 4

1.4 CASE STUDY 4

II DETAILED DISCRIPTION OF GENERATION

TRANSMISSION AND DISTRIBUTION

2.1 INTRODUCTION 5

2.2 CLASSIFICATION OF POWER SYSTEMS 6

III AP TRANSCO PLANNING CRITERIA

3.1 INTRODUCTION 93.2 TRANSMISSION PLANNING 10

REQUIREMENTS

3.3 SUBSTATION DATA 10

3.4 DISTRIBUTION LOAD FORECAST 11

3.4.1 SYSTEM LOAD FORECAST 11

3.4.2 GLOBAL LOAD FORECAST 11

3.5 PERSPECTIVE PLANNING 12

IV LOAD FLOW STUDIES ON SUBSTATION

4.1 INTRODUCTION 13

4.2 VOLTAGE SPREAD 13

4.3 EFECTS OF VOLTAGE SPREAD 15

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ON UTILIZATION EQUIPMENTS

4.4 INDUCTION MOTORS 16

4.5 VOLTAGE ZONES 17

4.5.1 FAVOURABLE ZONE

4.5.2 TOLERABLE ZONE

4.5.3 EXTREME ZONE

4.6 UTILIZATION EQUIPMENT VOLTAGE RATING 18

4.7 VOLTAGE DROP IN SYSTEM COMPONENTS 19

4.7.1 RESIDENTIAL FEEDERS

4.7.2 DISTRIBUTION FEEDERS

4.7.3 PRIMARY FEEDERS

4.7.4 RURAL FEEDERS

4.7.5 INDUSTRIAL FEEDERS

4.8 VOLTAGE REGULATION BASED ON P.F AND 25

D.F

4.8.1 POWER FACTOR

4.8.2 DIVERSITY FACTOR

4.9 METHODS OF IMPROVING VOLTAGE 26

REGULATION

V SOFTWARE DESCRIPTION 28

5.1 OPEN SYSTEMS 28

5.2 CUSTOMIZED GUI 28

5.3 FULL GRAPHICS 28

5.4 DIGITISATION 28

5.4.1 NETWORK

5.4.2 GEOGRAPHICAL INFORMATION

5.5 SYSTEM ANALYSIS 29

5.5.1 LOAD FLOW ANALYSIS

5.5.2 SHORT CIRCUIT STUDY

5.5.3 PROTECTIVE CO ORDINATION

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5.5.4 LOAD MODEL

5.6 SYSTEM PLANNING 29

5.6.1 TRENDS OF GROWTH

5.6.2 GLOBAL LOAD FORECAST

5.6.3 SPATIAL LOAD FORECAST

5.6.4 LOCATION AND SIZING OF SUBSTATION

5.6.5 PERSPECTIVE PLANS

VI CASE STUDY 32

MAPS

6.1 SINGLE LINE DIAGRAMS OF FEEDERS 32

6.2 CASE I 37

6.3 CASE II 38

6.4 HAND CALCULATIONS 42

6.5 OBSERVATIONS. 56

VII RESULTS 57

VIII CONCLUSION 64

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CHAPTER-1

INTRODUCTION

1.1 LOAD FLOW.

Power Flow studies are also known as load flow studies. The principal

information obtained from these studies is the voltage at each bus and real and reactive power

flowing in each line. There by calculates voltage regulation of each feeder, power flow in all

branches, feeder circuits, losses in each branch and total system power losses. A typical power

system single line diagram comprising generation, transmission and distribution is given below.

The main parts of power system are as follows:

1. Generating stations.

2. Transmission systems.

3. Distribution networks

The description about the following parts of the power system would be given in detail in

the next chapter.

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GENERATOR 11KV

TRANSFORMER 11KV/400 KV

400KV/220KV

EHV

TRANSMISSION

HT LOAD

33KV/11KV

HIGH VOLTAGE

DISTRIBUTION 11KV

11KV/0.4KV

LOW VOLTAGE DISTRIBUTION

0.4 KV

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1.2 IMPORTANCE OF LOAD FLOW

The importance of these studies is planning the future expansion of power

system as well as in determining the best operation of existing system. Load flow is an importanttool involving numerical Analysis applied to power system . Power flow analysis is very

important in planning stages of new networks in additional to existing ones.

It is helpful in determining the best location as well as optimal capacity of proposed generating

stations and substations

The conventional method of calculating voltage regulation is simple based onKVA KM loading of conductors.

Also, the conventional method to evaluate the demand loss (or) peak power

loss on a distribution feeder is based on the use of loss constants. The conventional technique is

simple but may not result in correct computation of loss for the following reasons:

The loss constants are obtained on the assumptions that voltage at all buses along the

length of feeder is the rated voltage.

The drop in voltage of the feeder from source to tail end and the consequent increase in

loss are not considered.

The demand loss in each feeder segment increases the power flow in all preceding

feeder segments up to the source. The effect of such loss is not considered in the demand loss

in each feeder segment increase the power flow in all preceding feeder segments up to the source.

The effect of such loss is not considered in the conventional method.

At present power utilization increased leaps and bounds thus posing requirement of bulk

generation and transmission of power. As in example generation installed capacity of AP is

15000 MW in 2011 a against 4065 MW in 1991 similarly the bulk power generated at pit heads

or projects need to be transported to the load centers necessitating EHV network that is

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operated at higher voltages i.e from 132 KV to 220 KV and much more to 400 KV and 765 KV

which is under progress. Ultimately all this power need to be deliver to the door steps of various

consumers through sub transmission and distribution networks. All these stages of power system

is capital oriented thus necessitating lot of studies for effective capital investment and

remunerative technically as well as economically.

Latest technology/ powerful software tools are finding place in calculating such

cumbersome calculations in power systems.

1.3 DISBUT SOFTWARE.

DISBUT software used in APTRANSCO is very accurate and well defined to

meet the above requirements.

The power flow techniques such as Newton- Raphson method, fast decoupled load

flow method etc, are used to solve well behaved power systems effectively. But, when these

techniques are applied to ill-conditioned (or) poorly initialized power systems have led to

many short comings . Whereas the DISBUT package is more suitable for calculating voltages,

currents, active and reactive power flowing in each line, there by voltage regulation and power

loss of radial feeders at different voltage levels ( i.e.., 33kv , 11kv etc).

1.4 CASE STUDY.

As a case study, the voltage regulation and power loss of the following 33kv

feeders were considered.

1. Mustyal ----------Tharigoppula

2. Raghunathpalli-----------Quilashapur

3. Jangoan-------------Gandiramaram

4. Jangoan------------ Adavikeshapur

5. Ghanpur------------Tadikonda

6. Ghanpur------------Malkapur

7. Mustyal-------------Dhoolmitta

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The results were analyzed duly applying optimization techniques like adding of a new

sections for alignment of loads on 33 KV side. Adding of new feeders and new 132/33KV

substations at optimal location was suggested.

CHAPTER-2

DETAILED DESCRIPTION OF GENERATION ,

TRANSMISSION AND DISTRIBUTION

2.1 INTRODUCTION:

Energy provides power to progress. We need energy in various forms like heat, light ,sound

etc .The development new technology made it possible to convert electrical energy into any form

of energy. This gives electrical energy an important position in the world. The running of the

modern industrial structure depends on the low cost and the uninterrupted supply of electricity.

In short we can say that a country is developed if the per capita consumption of electrical energy

is much higher.

Electrical energy is considered to be superior over other energy forms the following facts gives

the proof for it.

1. Convenient energy form: Electrical energy could be considered as the most

convenient form of energy as it could be converted from one form to another easily.

2. Flexibility: Another important aspect of electricity is the flexibility, it is very easy to

carry electricity from one place to other by using conductors

3. Cheapness: Electrical energy is much cheaper compared to other forms of energy.

The cost of production and availability is much larger compared to other forms of

energy and hence it is an inevitable component in all sectors of the modern world.

4. Cleanliness: Electrical energy is not associated with polluting factors such as smoke,

dust, fumes ,poisonous gases etc thus it offers a healthy atmosphere to each and all

living organism in the world.

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5. High Transmission Efficiency: The transmission efficiency of electrical energy

is much higher.

2.2 CLASSIFICATION OF POWER SYSTEM

The main parts of the electrical energy power system are:

Generating stations.

Transmission systems.

Distribution network.

2.2.1 Generating stations: electrical energy generation

Electrical energy is being generated in large hydro, thermal, and nuclear power stations

but the stations are located far away from the load centers. Large and long transmission

networks are wheeling the generated power from the sending end stations to sub stations

and the load centers. Several electrical equipments are pressed into service for proper

transmission and distribution of the generated power.

Economic dispatch is an important aspect to be studied in a power system. As generator

is the prime source of energy, hence economic operation of generators is very much

necessary to be analyzed.

Now a days, the major electrical equipment in power stations that is being used for

highest practical voltage for generation is 33kv though 11kv/12kv/13kv/15kv are the

most usual. If a generator is to feed a network at 33kv there is a strong case for

generation for 33kv as it will avoid the use of step up transformers.

There are two methods of electrical generations:

Conventional

Non-conventional

The conventional energy sources of electrical generations are

Thermal stations

Hydro electric stations

Nuclear power stations

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Diesel electric stations

The non-conventional energy sources of electrical generations are

Wind energy

Solar energy

Fuel cells

Tidal power generation

Geo-thermal energy

2.2.2 Transmission systems:

Electric-power transmission is the bulk transfer ofelectrical energy, from

generatingpower plantsto electrical substationslocated near demand centers.Transmission lines,

when interconnected with each other, become transmission networks. Transmission system

design will require a study of choice with reference to transmission voltage, constants of

transmission, design interference with neighboring communication circuits behind line insulation

and corona problems.

Electricity is transmitted athigh voltages(110 kV or above) to reduce the energy lost in

long distance transmission. There are two types of transmission lines which are as follows:

Overhead transmission lines

Underground transmission lines

Power is usually transmitted through overhead power lines. Underground power

transmission has a significantly higher cost and greater operational limitations but is sometimes

used in urban areas or sensitive locations.

2.2.3 Distribution network:

Electricity distribution is the final stage in the deliveryofelectricityto end

users. A distribution system'snetworkcarries electricity from the transmission systemand

delivers it to consumers. Typically, the network would include medium-voltage (less than 50 kV)

power lines, substations and pole-mounted transformers, low-voltage (less than 1 kV)

distribution wiring and sometimes meters. The modern distribution system begins as the primary

circuit leaves the sub-station and ends as the secondary service enters the customer's meter
http://en.wikipedia.org/wiki/Electrical_energyhttp://en.wikipedia.org/wiki/Power_planthttp://en.wikipedia.org/wiki/Electrical_substationhttp://en.wikipedia.org/wiki/Electrical_substationhttp://en.wikipedia.org/wiki/High_voltagehttp://en.wikipedia.org/wiki/High_voltagehttp://en.wikipedia.org/wiki/High_voltagehttp://en.wikipedia.org/wiki/Overhead_power_linehttp://en.wikipedia.org/wiki/Power_deliveryhttp://en.wikipedia.org/wiki/Electricityhttp://en.wikipedia.org/wiki/Electricityhttp://en.wikipedia.org/wiki/Grid_(electricity)http://en.wikipedia.org/wiki/Grid_(electricity)http://en.wikipedia.org/wiki/Electric_power_transmissionhttp://en.wikipedia.org/wiki/Electrical_substationhttp://en.wikipedia.org/wiki/Transformerhttp://en.wikipedia.org/wiki/Electricity_meterhttp://en.wikipedia.org/wiki/Electricity_meterhttp://en.wikipedia.org/wiki/Electrical_energyhttp://en.wikipedia.org/wiki/Power_planthttp://en.wikipedia.org/wiki/Electrical_substationhttp://en.wikipedia.org/wiki/High_voltagehttp://en.wikipedia.org/wiki/Overhead_power_linehttp://en.wikipedia.org/wiki/Power_deliveryhttp://en.wikipedia.org/wiki/Electricityhttp://en.wikipedia.org/wiki/Grid_(electricity)http://en.wikipedia.org/wiki/Electric_power_transmissionhttp://en.wikipedia.org/wiki/Electrical_substationhttp://en.wikipedia.org/wiki/Transformerhttp://en.wikipedia.org/wiki/Electricity_meter

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socket. Distribution circuits serve many customers. The voltage used is appropriate for the

shorter distance and varies from 2,300 to about 35,000 volts depending on utility standard

practice, distance, and load to be served. Distribution circuits are fed from a transformerlocated

in anelectrical substation, where the voltage is reduced from the high values used for power

transmission. Conductors for distribution may be carried on overhead

pole lines, or in densely-populated areas where they are buried underground. Urban and

suburban distribution is done with three-phase systems to serve both residential , commercial,

and industrial loads. Distribution in rural areas may be only single-phase if it is not economical

to install three-phase power for relatively few and small customers.

Only large consumers are fed directly from distribution voltages; most utility customers are

connected to a transformer, which reduces the distribution voltage to the relatively low voltage

used by lighting and interior wiring systems. The transformer may be pole-mounted or set on the

ground in a protective enclosure. In rural areas a pole-mount transformer may serve only one

customer, but in more built-up areas multiple customers may be connected. In very dense city

areas, a secondary network may be formed with many transformers feeding into a common bus

at the utilization voltage. Each customer has an "electrical service" or "service drop" connection

and a meter for billing. (Some very small loads, such as yard lights, may be too small to meter

and so are charged only a monthly rate.)
http://en.wikipedia.org/wiki/Transformerhttp://en.wikipedia.org/wiki/Transformerhttp://en.wikipedia.org/wiki/Electrical_substationhttp://en.wikipedia.org/wiki/Electrical_substationhttp://en.wikipedia.org/wiki/Three-phase_electric_powerhttp://en.wikipedia.org/wiki/Transformerhttp://en.wikipedia.org/wiki/Electrical_substationhttp://en.wikipedia.org/wiki/Three-phase_electric_power

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CHAPTER-3

AP TNANSCO PLANNING CRITERIA

3.1 INTRODUCTION

We all know electrical energy cannot be stored, it is getting utilized

simultaneously while generated. Also load is very dynamic which poses challenge to the

system operators. To balance generation and demand, the system operator shall be

facilitated with sufficient data bank of past trends of load and expected load in future over a

stipulated period. This knowledge of old data and predicted future is system planning. Also

power system planning is to provide an orderly and economic expansion to meet the utility

future electric demand and acceptable reliability. Correct planning requires a proper forecast.

The quality and accuracy of this forecast is crucial to electric utility since it dictates the

planning of generation, transmission and distribution facilities. If the forecast is understated

it results in shortage in generation capacity and in adequacy of transmission and distribution

facilities. Similarly if it is over stated the result is excessive financial investments in facilities

in advance of actual needs and there by blocking of scarce capital which could have been

otherwise utilized in a more profitable way.

Planning of system involves determining

The correct sizes

Location

Interconnection

Timing future additions to this equipment

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Such planning is a difficult task, compounded by resent trends in tightening the

design margins. Correct planning of capacity of equipment requires a forecast of future

geographical distribution of electric demand.

During last decade a number of practical and efficient automated computerized

methods have been developed as an aid to system planning and design and determine minimum

cost plan. These automatic produces produce substantial saving over traditional methods, but

require high resolution projection future loads. Therefore to gain maximum benefit from these

produces, development of accurate forecast methods have been subject of increasing attention

during last few years.

3.2 TRANSMISSION PLANNING REQUIREMENTS:

Basic requirements for carrying a transmission planning study are:

Information on the existing transmission facilities.

Load forecast

Generation planning

Information on the existing transmission facilities:

Collection of all the available information on the existing system forms the first stage in the

planning process. Data required is as given below. Data is usually available in the records

maintained at the substations. Basic parameters required are,

Transmission line data line voltage, number of conductors per phase, size and type of

conductor and shield wire.

Line resistance, resistance and susceptance (positive and zero sequence)

Thermal capacity

Size and location of line connected shunt reactors

Size and location of series capacitive compensation

3.3 SUBSTATION DATA

Data required for transmission planning purposes, at the substation level and for each year

consists of

Real and reactive demand (MW and MVAR)

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Peak and minimum demand

Seasonal variation of demand

Single line diagram and layout plan

Transformer rating, impedance, tap changer ranges and type

Transformer winding arrangement

Transformer grounding arrangement

Circuit breaker continues and interrupting current ratings

Shunt reactor/capacitor ratings

3.4DISTRIBUTION LOAD FORECAST CAN BE CLASSIFIED INTO:

3.4.1System load forecast :viz. , forecast of the load for entire study area.

Spatial or small area load forecast: viz. , divide the utility area in to sufficiently large

number of small areas and forecast for each small area. There are number of different approaches

small areas and forecasting generally falling into two categories viz., trending and simulation

methods.

I. Trending method: Trending methods produces the future electric demand by extrapolation

the past trends, or pattern of load growth in small areas.

II .Multivariate method: This method builds relationship with one set of data viz. customer

demand data, and another class of data set such as controlled data that is pattern of land use,

number of customers in each class etc. the demand variables are forecasted given historical and

future set of control variables.

III. Land used based simulation method: in this methoda mathematical relationship has

been developed between.

a. Changes in electric usage on per customer basis,

b. Changes in the number and location of customers which drives the geographic spread ofelectricity demand.

Trend methods requires historical demand data for last 4-5 years, whereas

multivariate and land use simulation, methods requires historical land use data and customer

number in each class and also future land use and customer spread in small area.

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Global load forecast:Evaluates the energy and demand of the study area globally on

Long term basis using, time series different trend curves, regression techniques linking energy

and demand to various demographic and economic factors and end use method.

3.5 PRESPECTIVE PLANNING:

APTRANSCO adopts trends method for conducting feasibility studies for the

planning of 132/33 KV substations in AP.

A Case load flow study is done on 33kv feeders from 132/33kv-

mustyal,Raghunathpally, Jangaon, Ghanapur substations was presented in this thesis.

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CHAPTER-4

LOAD FLOW STUDIES ON SUBSTATION

4.1 INTRODUCTIONThe primary objective of system voltage control is to provide power to each user at

specified voltage that is directed by regulator.Ideally, the output of most power supplies should be a constant voltage. Unfortunately,

this is difficult to achieve. Voltage drop exists in each part of the power system from the source

to the consumer service drop. It also occurs in interior wiring. System voltage regulation is

essentially no more than maintaining the voltage at the consumer service entrance with in

permissible limits by the use of voltage control equipment.

In general the voltage drop is the difference between the voltage at the transmitting and

receiving ends of a feeder, main or service. There are two factors that can cause the output

voltage to change. First, the ac line voltage is not constant. The second factor that can change the

dc output voltage is a change in the load resistance. Many circuits are designed to operate with a

particular supply voltage. When the supply voltage changes, the operation of the circuit may be

adversely affected. Consequently, some types of equipment must have power supplies that

produce the same output voltage regardless of changes in the load resistance or changes in the ac

line voltage.

4.2 VOLTAGE SPREAD:

It is the difference between maximum and minimum voltage at a particular point in the

distribution system. It will vary in magnitude depending upon the particular location within the

system where the spread is measured. An illustration of the voltage spreads occurring at the

utilization point is shown in the figure below.

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FIG:4.1

Consumer A, which is the first consumer served by the feeder, has a voltage spread of

just 1 volt when going from light load (230v) to heavy load (229v) conditions. Consumer B

which is the last consumer served by the feeder has a voltage spread of seven volts i.e: 218v at

heavy load conditions to 225v at light load conditions. The utilization voltage at consumers A or

B for load conditions between the maximum and minimum values of the respective voltage

spreads.

The voltage spread at the utilization point of any other consumer on the same feeder

would have a voltage spread with somewhere between one and seven volts, depending upon the

location.

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Similar voltage spreads are found at the utilization points of every consumer on the

system. The average voltage spread at the utilization points are generally wider for rural

distribution feeders than residential feeders or urban feeders. Consumers on urban feeders

generally have smallest average voltage spread because the feeders are shorter in length and the

conductor sizes are larger.

FIG:4.2

4.3 EFFECT OF VOLTAGE SPREAD ON UTILIZATION EQUIPMENT:

Whenever the voltage applied to the terminals of utilization device varies from the

rated or nameplate voltage of the device, performance characteristics and equipment life will also

change. The extent of the change may be minor or serious depending upon the device, how it is

applied, and how much the terminal voltage deviates from the nameplate rating.

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Voltage drop will result in huge losses in network.

4.3.1 SOME MORE EFFECTS DUE TO VARIATION OF VOLTAGE ARE AS

FOLLOWS:

Lamps: a 10% reduction in lamp voltage results in a 30% reduction in light output it

means 30% of the investment is lost.

Fluorescent lamps will operate satisfactorily over a wide range of voltage spread and

their life is less affected. In general 1% variation in line voltage will change the

lumen output only by about 1%

Electronic equipment: the emission of all electron tubes is affected seriously by voltage

variation. The cathode life is curve indicates that the life is reduced by half for each 5%

increase in cathode voltage.

Capacitors: the kilowatt output of capacitors varies with the square of the impressed

voltage . a drop 10% in the supply voltage reduces the kilowatts by almost 20% .

4.4 INDUCTION MOTORS:

as voltage fails below rated rated voltage the starting torque reduces substantially,

because starting torque varies as the square of the applied voltage.

For an applied voltage 10% below rated voltage, the starting torque decreases to

81% of normal.

The reduction in the starting torque with low voltage may be significant and costly

in motor applications., driving high inertia equipment.

The table lists the general effects of voltage variation on induction motor.

Voltage variation

90% voltage Function of

voltage

110% voltage 120% voltage

Starting and

maximum

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1)Running

torque

2)Synchronous

speed

3)% slip

4)Full load

speed

Decreases

19%

No change

Increases 23%

Decreases 11/2

(voltage)2

Constant

1/(voltage)2

(syn. Speed-

slip)

Increases 21%

No change

Decreases

17%

Increases 1%

Increases 44%

No change

Decreases

30%

Increases1.5%

Efficiency

1)full load

2)3/4 load

3)1/2 load

Decrease 2 pt

Practically no

change

Increases 1 to

2 pts

-------

-------

-------

Increases to

1 pt

Practically no

change

Decreases 1 to

2 pts

Small increase

Decreases to

to 2 pts

Decreases 7 to

2 pts

Power factor

1)full load

2)3/4 load

3)1/2 load

4)Full load

current

Increases 1 pt

Increases 2 to

3 pts

Increases 4 to

5 pts

Increases 11%

-------

-------

-------

-------

Decreases 3

pts

Decreases 4

pts

Decreases 5 to

6 pts

Decreases 7%

Decreases 5 to

15 pts

Decreases 10

to 30 pts

Decreases 15

to 40 pts

Decreases

11%

Starting

current

Decrease 10

to 12%

voltage Increases 10

to 12%

Increase 25%

Temp rise ,full

load

Increase 6-7

degree

centigrade

--------

Decraeses 3-4

degree

centigrade

Decreases 5-6

degree

centigrade

Maximum

overload

capacity

Decreases

19%

(voltage)2 Increases 21% Increases 44%

Mag.noise- no Decreases Increases Noticeable

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4.6 UTILIZTION EQUIPMENT VOLTAGE RATINGS:

The design (nameplate) voltage of utilization equipment is generally matched to the

utilization voltage that occurs during the time when it is most frequently used. Appliances which

are used for long duration and during any load conditions, light or heavy have design voltages the

same as nominal system voltage. Appliances of shorter time usage and relatively high demands

have a design voltage slightly less than nominal also the voltage spread used s a basis of design

for utilization equipment will vary depending upon the time usage and demand. For eg: the small

household cooking appliances have design voltage spread of 100 to 120 volts, while the large

household cooking appliances have design voltage spread of 107 to 122 volts.

4.7 VOLTAGE DROP IN SYSTEM COMPONENTS:

The system component voltage drop will be discussed only for the various types of

feeders from the location on the feeder of the first consumer served to the last.

4.7.1 RESIDENTIAL FEEDERS:

The voltage at the point of utilization when keeping with in the favorable zone can be 217

to 230 volts. The logical primary feeder designed to permit maximum loading and area coverage

is to permit the first consumer electrically nearest to the source to have maximum voltage of 230

volts during maximum load conditions. The most remote consumer electrically from the source to

have the minimum permissible voltage of 217 volts. The average voltage drop for residential

interior wiring during maximum load conditions is approximately three volts; hence, to have the

utilization voltage no lower than 217volts, the voltage at the consumers service entrance or meter

socket must be 220volts or above.

The feeder components of a residential feeder are shown in one-line diagram below.

Studies of residential feeder design have shown that at a definite amount of voltage drop can be

allocated to each component for maximum economy.

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FIG:4.7.1 Residential Feeder

4.7.1(A) SERVICE DROP:

The voltage drop most generally found for service drops during heavy load conditions

is 1 volt.

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4.7.1(B) SECONDARY LINE:

Secondary conductors when installed generally have a voltage drop of approximately two

to two and half volts, and as load increases the voltage drop is permitted to increase to three or

three and half volts. When the voltage drop reaches the upper limit another

distribution transformer is added between the existing, and the secondary line is split between the

new and existing units. Such a procedure reduces the secondary voltage drop to less than 1 volt.

4.7.2 DISTRIBUTION TRANSFORMER:

At the time of installation in a developed residential area, the transformer

loading during peak periods is generally 80 to 100 percent. For the average distribution

transformer rating this represents a voltage drop of 1.75 to 2.5 volts the transformer remains in

service until the peak load increases to about 140 to 160 percent. This represents a voltage drop

of 3.25 to 4 volts. The amount of voltage drop allocated to the distribution transformer out of the

permissible 12 volts spread is generally 3 volts.

4.7.3 PRIMARY FEEDERS INCLUDING LATEARLS:

The voltage drop allocated to the primary portion of the residential feeder is 3 volts, on a

120-volt base, and is as measured from the primary terminals of the first distribution transformer

on the feeder to the last or most remote transformer electrically. Where single phase laterals are

tapped off the three phase main, they generally have a voltage drop from one to three volts, with

the last lateral having about one volt drop, and the lateral tapped off near the first distribution

transformer on the feeder three volts.

4.7.4 RURAL FEEDERS:

Rural feeders are also similar to residential feeders. Length of the feeders is more i.e 5 to

10 times longer in rural feeder. Age loads play predominant role in rural feeders which contribute

poor power factor thus more voltage drops.

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FIG: 4.7.4 Rural Feeder

Below table shows typical voltage drop allocations for rural feeder components. The table

values keep the service voltage within the favorable zone. Even with the increased primary line

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drop as compared to the residential feeder, it is often necessary to add some supplementary

voltage boost out on the feeder.

FEEDER

COMPONENTS

RESIDENTIAL

FEEDER

RURAL

FEEDERMAXIMUM

LOAD

CONDITION

MINIMUM

LOAD

CONDITION

MAXIMUM

LOAD

CONDITION

MINIMUM

LOAD

CONDITION

Primary feeder From

first distribution

transformer to

Last

Distribution

Transformer

3.5

1.0 6 2.0

Distribution

transformer3

1.0 3 1.0

Secondary line

3.5

1.0

Total

11.0 volts 3.3 volts 11.0volts 4.0 volts

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4.7.5 INDUSTRIAL FEEDERS:

Industrial feeders are relatively short feeders and serve any where from one to several

consumers. They are similar to rural feeders, in that there are generally no secondaries, as each

consumer has his own transformer. Many industrial consumers purchase energy directly at the

primary voltage level and own the step-down transformer.

There are no recommended allocations of voltage drop for industrial feeder

components. Each industrial consumer on a feeder should have the supply voltage to the

transformer or transformers which serve the plant fall within the zone shown in columns 2 and 3

in the below table .The voltage spread for the primary supply should be four percent and should

fall within the recommended voltage zone.

NOMINAL

SYSTEM

VOLTAGE

ZONE OF VOLTAGES OF

PRIMARY ON

TRANSFORMERS

PRIMARY VOLTAGE

SPREAD

COLUMN 1

VOLTS

COLUMN 2

MINIMUM

VOLTS

COLUMN 3

MAXIMUM

VOLTS

COLUMN 4

% OF

COLUMN 1

COLUMN 5

VOLTS

2400

4160

4800

6900

11500

13300

2130

3680

4260

6100

10200

12200

2520

4360

5040

7250

12100

14500

4%

4%

4%

4%

4%

4%

100

170

190

280

460

550

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TABLE: 4.7.5 Industrial Feeders

4.8 VOLTAGE REGULATION BASED ON POWER FACTOR ANDDIVERSITY FACTOR:

As we know that voltage regulation is the difference between the maximum and

minimum voltage at a point in the distribution system, it can be based on the following

Power factor

Diversity factor

4.8.1 POWER FACTOR :Poor power factor of load results in bad or very high voltage regulation. Power factor of some

of the common types of loads are given below:

LOAD

POWER FACTOR

Incandescent lamp

Arc lamps used in for advertisements

Florescent lamps

Fans

Electric drills

Resistance heaters

Induction heaters

Arc furnaces

Arc welders

Resistance welders

Induction motors

1.0

0.3 to 0.7

0.4 to 0.5

0.6 to 0.8

0.5 to 0.8

0.9

1.0

0.85

0.85

0.3 to 0.4

0.65

0.4 to 0.8

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With the increasing trend to use more motorized gadgets by the domestic consumers, the power

factor of the system will further decrease. It is not practicable to impose power restrictions on the

small individual consumers.

4.8.2 DIVERSITY FACTOR:

There is general tendency to assume high diversity factor at the designed stage of feeders in

order to reduce the cost f the scheme and thus make the same remunerative as per the

departmental standards. Reasonable diversity factors for 11 kv and LT feeders are 3 and 1.5

respectively. While these serve as general guide the diversity factors can be different provided

they can substantiated with actual diversity factors obtainable in a particular area of feeder. The

departmental practice at present is to design the 11 kv feeders for 10% regulation with DF of 2.5

or 3 and LT FEEDERS FOR 5% regulation may be adopted for LT feeders when the distribution

transformer LT voltage in 433 volts as this would still satisfy the IE rules.

4.9 METHODS OF IMPROVING VOLTAGE REGULATION:

There are several methods of improving voltage regulation throughout the distribution system.

The various methods of improving voltage regulation through a distribution system are listed

below. Each method has its own characteristics concerning amount of voltage improvement, cost-

per-volt improvement, and flexibility.

1. Use of generator voltage regulators.

2. Application of voltage regulation equipment in the distribution substations.

3. Application of capacitors in the distribution substation.

4. Balancing of the loads on the primary feeder.

5. Increasing of feeder conductor size.

6. Changing of feeder sections from single-phase to multi-phase.

7. Transferring of loads to new feeders.

8. Installing of new substations and primary feeders.

9. Increasing of primary voltage level.

In order to evaluate the performance of a power distribution network and to examine

the effectiveness of proposed alterations to a system in the planning stage, it is essential that a

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load flow analysis of the network is carried out. The load flow studies are normally carried out to

determine:

The flow of active and reactive power in network branches.

No circuits are overloaded, and the bus bar voltages are within acceptable limits.

Effect of additions or alterations on a system such as voltage regulators, shunt & series

capacitors.

Effect of loss of circuits under emergency conditions.

Optimum system loading conditions.

Optimum system losses.

The load flow in distribution networks is carried out for simple radial networks in

this project, which is largely self evident.

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CHAPTER-5

SOFTWARE DESCRIPTION

The code DISBUT developed by A.P.S.E. Board aims to meet the requirements of the

distribution system planning and design. It is a complete integrated code for Computer Aided

Distribution System analysis optimization.

5.1 OPEN SYSTEMS:

DISBUT is based on open systems concept using UNIX operating system conforming

to IEEE POSIX standards, X-windows and X lib. The software is capable of working in

networking environment on DEC, SUN, HP, SG, IBM workstations and one can choose the

workstation platform of their choice.

5.2 CUSTOMISED GUI:

DISBUT is totally user friendly and interactive with Customized Graphical User

Interface (GUI) with features like pop up menus to select options, dialogue boxes to enter data

interactively and with scroll bar frames to display results.

5.3 FULL GRAPHICS:

Implements full graphics interface, providing zooming & panning and de cluttering functions.

Zoom & pan allows user to view a particular area in detail. De cluttering allows user to define the

level of details to be displayed.

5.4 DIGITISATION

5.4.1NETWORK:

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DISBUT provides a powerful tool to digitize the electrical distribution network with

all its entities like substations, transformers, capacitors, regulators, branches, and links including

graphic points and their connectivity and also creates spatial and network connectivity data bases.

Facility to edit network like add, modify and delete any entity is provided. Facility to input

transformer capacity at each bus while digitizing the network and calculate length of line

segments based on scale map are provided.

5.4.2 GEOGRAPHICAL INFORMATION:

The geographical features of area like administrative boundaries, roads, rivers, tanks

etc.., can be digitized creating a true life image of field conditions.

5.4.3 SINGLE LINE DIAGRAM:

Creates a single line diagram of each feeder to display network parameters or study

5.5 SYSTEM ANALYSIS:

5.5.1 LOAD FLOW ANALYSIS:

Load flow analysis is made to identify pockets of low voltage and high power

losses, using a special iterative radial load flow algorithm, which guarantee convergence in 2 or 3

iterations, even for the ill conditioned feeder with 20% or 30% voltage drops, with accurateresults. Facility to conduct load flow analysis of multi voltage networks and 3phase load flow

analysis for unbalanced and unsymmetrical networks is also provided.

5.5.2 SHORT CIRCUIT STUDY:

Computes the fault current and fault MVA at each bus for single phase to ground and

three phase faults with fault impedances.

5.5.3PROTECTIVE COORDINATION: Provides protective coordination of relay and fuses in the network.

5.5.4 LOAD MODEL:

Evaluates annual load factor, loss factor and load duration curve of a feeder or substation.

5.6 SYSTEM PLANNING

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5.6.1TRENDS OF GROWTH:

Evaluates the trend parameters of load development for different tariff categories

from historical load data and displays trend curves.

5.6.2 GLOBAL LOAD FORECAST:

Evaluates the energy and demand of the study area globally on Long term basis

using, time series different trend curves, regression techniques linking energy and demand to

various demographic and economic factors and end use method.

5.6.3SPATIAL LOAD FORECAST:

Distribution planning requires quantum, location and timing of load growth, for each

small area. The module determines the demand of each small area using time series of different

trend curves and Land use based simulation techniques, considering development plans of the

state and local authorities.

5.6.4LOCATION & SIZING OF SUBSTATION:The module determines the number, location and size of Distribution substations for

least cost system expansion plan over long term period by minimizing fixed charges of

substations and cost of network losses.

User has to give the potential substation sites and the feasible capacity options at

each location. The program generates optimal and sub-optimal solutions determining the number,

location and capacity of substations and the total cost of plan, in three steps. First step creates

node loss table indicating the incremental losses in the network, when each node is fed from a

given substation using principle of shortest path of algorithm and modeling losses as quadratic

function. Second step creates minimal power loss tree, considering the constraints of substation

size, voltage drop and load transfer using Zero one voltage drop and load transfer using Zero One

programming. Third step generates optimal and sub-optimal feasible solutions using Branch and

Bound techniques.

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Another algorithm based on growth rate of KVAOHM of feeder is provided to

choose optimal substation locations from potential sites. KVAOHM of a feeder is defined as the

sum of products of power flows and resistance of line segments constituting the feeder. This

algorithm gives good results in the absence of Spatial load forecast as it considers load growth

and its location and is useful to utilities in developing countries where spatial load forecast may

not be available.

5.6.5 PERSPECTIVE PLANS:

Develops Perspective Plans for Distribution system expansion for a given period,

giving Physical and Financial Estimates.

The above package is used in APTRANSCO, for conducting load flow studies for

future plans, optimal utilization of existing network and minimize losses due to over loading etc.

As a case study load flow of 33kv feeders from 132/33kv mustyal,

Raghunathpally, Janagon, Ghanapur, substations was presented in this thesis

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CHAPTER 6

CASE STUDY

The load flow was carried out on the following 7nos 33 kV feeders in Warangal districtwith actual data. Individual single line diagrams are given below with actual distances and

connected load are self explanatory:

6.1 FEEDER DIAGRAMS:

(i) FEEDER 1:MUSTYAL THARIGOPPULA ANKSHAPUR2095KVA

REBARTHY3325KVA

MUSTYAL 3.7 KM 3.16 KM

6.25 KM 13.24 KM

6.98KM THARIGOPPULA5050KVA

VELDANDA

3067KVA

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(ii)FEEDER 2: RAGUNATHAPALLY-QUILASHPUR

RAGHUNATHPALLY NARMETTA5.33KM 5.92KM 5.53KM 0.83KM

4477KVA

QUILASHAPUR 0.67KM 4KM

3991KVA

MEKALAGUTA

1400KVA

ADDABATA

1714KVA

(iii)FEEDER 3: JANGAON-GANDIRAMARAM

JANGAON BOMMAKUR15.27 KM 7500KVA

8.53 KM

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GANDIRAMARAM

7500KVA

(iv) FEEDER 4: JANGAON-ADAVIKESHAPUR

JANGAON ADAVIKESHAPUR

14.55 KM 5000KVA

2.

72 KM

HANU MANTHAPUR

5000KVA

(v) FEEDER 5: GHANPUR- TADIKONDA

GHANAPUR THATIKONDA

8.02KM 5000KV

4.66KM

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5000KVA

FATEHPURAM

(vi) FEEDER 6: GHANAPUR MALKAPUR

RAHAVARAM

5000KVA

GHANAPUR

5.3KM 1.45KM 1.11KM 9.63KM 3.95KM

2.56 KM PICHARA

MALKAPUR 5000KVA10000KVA

PEDDAPENDIAL

8150KVA

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(vii) FEEDER 7: MUSTYAL-DHOOLMITTA

MUSTYAL MUSTYAL DHOOLMITTA

10000KVA0.9 KM 7.09 KM 5.84 KM

2.66 KM

AKUNUR5000KVA

BEKKAL

5000KVA

3.64 KM

KUTTIGAL

3100KVA

The study was carried out assuming the load is balanced and pf was constant i.e., 0.8

Two types of studies are conducted one with optimization techniques like add feeder,

section or shunt capacitor etc presented as case I. Second study by proposing a new 132/33 kV

SS in the scheme area that is at Narmetta with 5nos new 33 kV feeders as case-II. In both the

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cases projection of load growth for 5 years at the rate of 9.7% is also calculated as per the

planning criteria of APTRANSCO

According to load flow studies the voltage regulations are as follows:

Sl.

No.

Name of the 33 kV feeder No. of

33/11

kV SS

Name of the

33/11 kV SS

% Voltage Regulations

BaseYear

Horizonyear

1. Mustyal - Tharigoppula 4 Rebathy,Veldanada,

Tharigoppula,Ankshapur(P)

8.46 13.44

2. Ragunathpalli- Quilashapur 4 Quilashapur,Mekalagattu

Narmetta,

Addabata

5.97 9.48

3. Jangoan - Gandiramaram 2 Gandiramaram (LI),Bommakur (LI)

14.20 14.20

4. Jangoan - Adavikeshapur 2 Hanmathapur,Adavikeshapur

3.78 6.01

5. Ghanpur -Tadikonda 2 Tadikonda,Fatehpuram

1.87 2.97

6. Ghanpur - Malkapur 4 Peddapendial,Malkapur,

Rajavarm,Peechara

10.01 15.90

7. Mustyal - Dhoolmitta 5 Mustyal,Aknuru,Dhoolmitta,

Bekkal,

Kutigal

8.70 13.82

TABLE 6.1: Voltage regulations at base year

As per the above results, the voltage regulation on feeders 3&6 are beyond permissible limits in

base year. Voltage regulations on feeders at Sl No. 1,2,&7 is beyond permissible limits at the

horizon year . Jangoan Gandiramaram (Sl No. 3) is independent feeder feeding a constant

load, hence projection of load for horizon year is not allowed.

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6.2 CASE-I

1. 2 MVAR capacitor banks proposed at Tharigoppula to improve voltage regulation onfeeder at Sl no: (1).

2. 2 MVAR capacitor banks is proposed at 33/11 kV SS Addabata SS to improve

voltage regulation on feeder at Sl no (2).

3. A new 33 kV feeder is proposed from Raghunathpalli SS to Gandiramaram toimprove voltage regulation on feeder at Sl n: (3)

4. A new 33 kV feeder is proposed from Ghanapur SS to improve voltage regulation on

feeder at Sl no (6) and also 2MVAR capacitor banks at 33/11 Pechara SS.5. A new 33 kV feeder is proposed from Mustyal SS to kutigal to improve voltage

regulation on feederat Sl no: (7).

The voltage regulations are given below table.

Sl.

No.

Name of the 33 kV feeder No. of

33/11kV SS

Name of the

33/11 kV SS


Base

Year

Horizon

year

1. Mustyal - Tharigoppula 3 Rebathy,

Veldanada,

Tharigoppula,

4.91 7.81

2. Ragunathpalli- Quilashapur 4 Quilashapur,

MekalagattuNarmetta,

Addabata

4.79 7.56

3. Jangoan - Gandiramaram 1 Bommakur (LI)

5.08 5.08

4. Jangoan - Adavikeshapur 2 Hanmathapur,Adavikeshapur

3.78 6.01

5. Ghanpur -Tadikonda 2 Tadikonda,Fatehpuram

1.87 2.97

6. Ghanpur - Malkapur 2 Peddapendial,Rajavarm,

2.05 3.25

7. Mustyal - Dhoolmitta 3 Mustyal,Aknuru,

Dhoolmitta,

4.81 7.65

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8 MUSTYAL-KUTIGAL 3 KUTIGAL,Bekkal,Ankushapur

4.63 7.35

9 Ragunathpalli-Gandiramaram

1 Gandiramaram 5.63 5.63

10 Ghanpur - Peechara 2 Peechara, Malkapur 4.99 7.92

6.3 Case II:Studies were also conducted by proposing new 132/33 kV SS in the scheme area is at Narmettawith 5 nos new feeders as the listed below:

Sl.No Name of 33 kV feeder

Length of

new

33kV

line(Km)

Name of 33/11 kV

SS to be transferred

No. of

SS s to betransferred

to new SS

1 Narmetta Narmetta 1Narmetta,

Addabata

2

2.Narmetta - Gandiramaram

5Gandiramaram 1

3.Narmetta Tharigoppula

6Tharigoppula,

Ankushapur

2

4. Narmetta Kutigal 10 Kutigal,Bekkal

2

5.Narmetta Malkapur

15Malkapur 1

The voltage regulations new 132/33 kV SS are given below table.

Sl.No.

Name of the 33 kV feeder No. of33/11

kV SS

Name of the33/11 kV SS


BaseYear

Horizonyear

1. Mustyal - Tharigoppula 2 Rebathy,Veldanada,

2.65 4.21

2. Ragunathpalli- Quilashapur 2 Quilashapur,

Mekalagattu

1.47 2.34

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3. Jangoan - Gandiramaram 1

Bommakur (LI)

5.08 5.08

4. Jangoan - Adavikeshapur 2 Hanmathapur,

Adavikeshapur

3.78 6.01

5. Ghanpur -Tadikonda 2 Tadikonda,Fatehpuram 1.87 2.97

6. Ghanpur - Malkapur 3 Peddapendial,

Rajavarm,Peechara

3.79 6.03

7. Mustyal - Dhoolmitta 3 Mustyal,

Aknuru,Dhoolmitta,

4.81 7.65

8 Narmetta-narmetta 2 Narmetta,

Addabata

0.60 0.95

9 Narmetta- Gandiramaram 1 Gandiramaram 1.39 1.39

10 Narmetta- Tharigoppula 2 Tharigoppula,Ankushapur

2.01 3.19

11 Narmetta-kutigal 2Kutigal,

Bekkal

1.99 3.16

12 Narmetta-- Malkapur 1 Malkapur 5.06 8.03

TABLE 6.3.2: Details of the voltage regulations after erection of substation.

Any of the two cases may be implemented duly considering other criteria like financial

viability and field conditions.

6.4. CALCULATION OF VOLTAGE REGULATION BY

CONVENTIONAL METHOD:

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Voltage regulation on sub transmission or on distribution feederswhich are radial feeders are also calculated through conventional method byassuming regulation constants per 100kva per km.

The regulation constants for commonly used conductors are

given bellow:

DETAILS OF THE

CONDUCTOR

% REGULATION PER 100KVA PER KM

415 KV 11KV 33KV

7/2.00 (SQUIRREL) 20sq.mm

7/2.00 (WEASEL) 30sq.mm

7/3.15 (RABBIT) 50sq.mm

7/4.26 (DOG)

100sq.mm

83.75

59.4

40.09

-

0.1211

0.08062

0.05853

0.03294

-

-

0.0064

0.00394

TABLE 6.4: Details of the conductors.

FORMULA:

Total KVA KM x regulation constant per 100 KVAper KMPercentage regulation =-------------------------------------------------------------------------------

100x Diversity Factor

Here diversity factor is taken as constant 1.

CONVENTIONAL CALCULATION

FEEDER 1: MUSTYAL - THARIGOPPULA

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REBARTHY ANKSHAPUR

3.7 KM3.16KM

MUSTYAL

6.25KM 13.24KM

6.98KMTHARIGOPPULA

VELDANDA

= 98424.5

CALCULATION OF % REGULATION ON EACH FEEDER

CALCULATIONS:

KVA at ANKSHAPUR = load on the feeder x the distance from the feeder to the substation.

= 2095 x (13.24+6.25+3.16)

= 2095 x 22.65

= 47451.75

KVA at THARIGOPPULA= 5050 x (13.24+6.25)

= 5050 x 19.49

= 98424.5

KVA at VELDANDA = 3067 x (6.98+6.25)= 3067 x 13.23

.= 40576.41

KVA at REBARTHY = 3325 x (3.7+6.25)

= 3325 x 9.25

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= 30 756.25

Total KVA KM = 47451.75+98424.5+40576.41+30 756.25= 217208.91

% regulation = total KVA KM x constant factor /100

= 217208.91 x 0.00394/100

=855.80311/100= 8.55%

FEEDER 2: RAGUNATHAPALLY-QUILASHPUR

RAGHUNATHPALLY NARMETTA

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5.33KM 5.92KM 5.53KM 0.83KM

QUILASHAPUR 0.67KM 4KM

MEKALAGUTA

ADDABATA

CALCULATION:

KVA at NARMETTA= 4477 x (0.83+05.53+5.92+5.33)

= 4477 x 17.61

= 78839.97

KVA at ADDABATA= 1714 x (4+5.53+5.92+5.33)

= 1714 x 20.78

= 35616.92

KVA at MEKALGUTTA = 1400 x (0.67+5.92+5.33)

= 1400 x 11.92

= 16688

KVA at QUILASHAPUR = 3991 x 5.33

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JANGAON ADAVIKESHAPUR 14.55 KM

2.72 KM

2286KVA

HANUMANTHAPUR

CALCULATION:

KVA at HANUMANTHPUR = 2286 x (2.72+14.55)

= 2286 x 17.27

= 39479.22

50

KVA at ADAVIKESHAVPUR = 3239 x 14.55

= 47127.45

Total KVA KM = 39479.22+47127.45

= 86606.67

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GHANAPUR THATIKONDA

8.02KM 3070KVA

4.66KM

1500KVA

FATEHPURAM

CALCULATION:

KVA at FATEHPURAM = 1500 x (4.66+8.02)

= 1500 x 12.88

= 19320

KVA at THATIKONDA = 3070 x 8.02

= 24621.4

Total KVA km = 19320+24621.4

= 43941.4

% Regulation at FATEHPURAM = 43941.4 x 0.00394/100

= 1.73%

FEEDER 6: GHANAPUR MALKAPUR

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RAHAVARAM

GHANAPUR

5.3KM 1.45KM 1.11KM 9.63KM 3.95KM

MALKAPUR PICHARA

2.56 KM

4001KVA

PEDDAPENDIAL

CALCULATION:

KVA at PICHARA = 2744 x (3.95+9.63+1.45+5.3)

= 2744 x 20.33

= 55785.52

KVA at MALKAPUR = 9297 x (9.63+1.45+5.3)

= 9297 x 16.38

= 152284.86

KVA at RAJAVARAM = 4573 x (1.45+5.3+1.11)

= 4573 x 7.86

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= 35943.78

KVA at PEDDAPENDIYALA = 4001 x (2.56+5.3)

= 4001 x 3.09

= 12363.09

Total KVA km = 55785.52+152284.86+35943.78+12363.09

= 256377.25

% Regulation at PICHARA = 256377.25 x 0.00394/100

= 10.10%

FEEDER 7: MUSTYAL-DHOOLMITTA

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MUSTYAL 5000 KVA

MUSTYAL DHOOLMITTA

0.9 KM 7.09 KM 5.84 KM

8955 KVA

2.66 KM

3.43 KM

AKUNUR

BEKKAL

5000 KVA

3.64 KM

KUTIGAL

3100 KVA

CALCULATION:

KVA at KUTIGAL = 3100 x (3.64+3.43+5.84+7.09+0.9)

= 3100 x 20.09

= 62279

KVA at BEKKAL =2854 x (3.43+5.84+7.09+0.9)

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= 2854 x 17.26

= 49260.04

KVA at DHOOLMITTA = 8955 x (5.84+7.09+0.9)

= 8955 x 13.83

= 123847.65

KVA at AKUNUR = 2705 x (2.66+7.09+0.9)

= 2705 x 10.65

= 28808.25

KVA at MUSTYAL = 8478 x 0.9

= 7630.2

Total KVA km = 62279+49260.04+123847.65+28808.25+7630.2

= 271825.14

% Regulation at MUSTYAL = 271825.14 x 0.00394/100

= 10.70%

6.5 OBSERVATIONS:

1. MUSTYAL-THARIGOPPULA

We can observe here that when we calculate voltage regulation through hand, the voltage

regulation at this feeder is 8.55 and system analysis gives the result as 8.46.

2. RAGUNATHPALLY- GANDIRAMARAM

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3.JANGAON- GANDIRAMARAM



4.JANGAON- ADAVIKESHAPUR



5. GHANPUR- TADIKONDA



6. GHANPUR- MALKAPUR

We can observe here that when we calculate voltage regulation through hand, the

voltage regulation at this feeder is 10.10 and system analysis gives the result as 10.01.

7. MUSTYAL-DHOOLMITTA



From the above all results and analysis we can observe that the voltage regulations

obtained through conventional method are more than the results of voltage regulation obtained

from system analysis.

Therefore we can concludes that system analysis for load flow studies is the most

appropriate method.

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CHAPTER 7

RESULTS

7.1 BASE STUDY

TABLE: FEEDER DATA

Feeder

no.

Name of the

feeder

no. of

substation

Transformer

s capacitykva

Load

factor

Length

km

Starting

voltagekv

12

3

4

56

7

Mstl-tgplRgpl-qspr

Jgn-grvm

Jgn-akpr

Gpr-tkdGpr-mkpr

Mstl-dmt

44

2

2

24

5

2500020000

15000

10000

1000028150

35000

0.500.50

0.50

0.50

0.500.50

0.50

33.3322.28

23.80

17.27

12.6824.20

23.56

33.0033.00

33.00

33.00

33.0033.00

33.00

total 23 143150 157.12

TABLE: FEEDER ANALYSIS

Feederno.

Name ofthe feeder

Activeload kw

Reactiveload

kvar

Energyloss l.u

Powerlosskw

% reg %energy

loss

1

2

34

5

67

Mstl-tgpl

Rgpl-qspr

Jgn-grvmJgn-akpr

Gpr-tkd

Gpr-mkprMstl-dmt

11464.

8759.

13451.4559.

3708.

14712.15629.

8850.

6703.

10664.3475.

2802.

11419.12008.

16.69

8.84

38.273.66

1.37

25.5218.95

635.

336.

1456.139.

52.

971.721.

8.46

5.97

14.203.78

1.87

10.018.70

3.32

2.30

6.501.84

0.84

3.962.77

total 72283. 55919. 113.29 4311. 14.20

maximum

3.58

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7.1 CASE-1: AFTER ADDING FEEDERS AND CAPACITOR BANKS.

BASE YEAR:TABLE

S.No Name of

the feeder

no. of

substation

Transformer

s capacitykva

Load

factor

Length

km

Starting

voltage kv

1

2

34

5

6

78

9

10

Mstl-tgpl

Rgpl-qspr

Jgn-grvmJgn-akpr

Gpr-tkd

Gpr-mkpr

Mstl-dmtMstl-ktl

Rgpl-grvm

Gpr-pcr

3

4

12

2

2

33

1

2

20000

20000

750010000

10000

13150

2500015000

7500

15000

0.50

0.50

0.500.50

0.50

0.50

0.500.50

0.50

0.50

31.82

22.28

20.9217.27

12.68

12.63

18.1223.20

16.83

16.54

33.00

33.00

33.0033.00

33.00

33.00

33.0033.00

33.00

33.00total 23 143150 192.29

FEEDER ANALYSIS:

Feederno.

Name of thefeeder

Activeload in

kw

Reactiveload in

kvar

Powerloss kw

Energyloss l.u

% reg %energy

loss

1

234

5

6

78

9

10

Mstl-tgpl

Rgpl-qsprJgn-grvmJgn-akpr

Gpr-tkd

Gpr-mkpr

Mstl-dmtMstl-ktl

Rgpl-grvm

Gpr-pcr

9470.

8684.6269.4559.

3708.

5816.

11793.5277.

6300.

8355.

5419.

4797.4809.3475.

2802.

4401.

8958.4037.

4844.

4590.

316.

261.269.139.

52.

100.

286.199.

300.

328.

8.31

6.857.083.66

1.37

2.62

7.515.22

7.89

8.61

4.91

4.765.083.78

1.87

2.05

4.814.63

5.63

4.99

2.00

1.802.581.84

0.84

1.03

1.452.26

2.86

2.35

total 70231. 48132. 2250. 59.12 5.63 1.92

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HORIZON YEAR:

Feeder

no.

Name of the

feeder

Source

load kw

Power loss

kw

Energy

loss l.u

% reg % energy

loss

123

4

5

67

8

910

Mstl-tgplRgpl-qsprJgn-grvm

Jgn-akpr

Gpr-tkd

Gpr-mkprMstl-dmt

Mstl-ktl

Rgpl-grvmGpr-pcr

15044.13796.6269.

7243.

5891.

9239.18735.

8383.

6300.13273.

798.658.269.

352.

131.

251.721.

501.

300.827.

20.9817.307.08

9.25

3.45

6.6118.94

13.18

7.8921.73

7.817.565.08

6.01

2.97

3.257.65

7.35

5.637.92

3.182.862.58

2.92

1.34

1.632.31

3.59

2.863.74

Total 104174. 4810. 126.41

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TABLE: FEEDER ANALYSIS AT HORIZON YEARHORIZON YEAR:2015

Feederno. Name of thefeeder Source loadkw Powerloss kw Energyloss l.u % reg % energyloss

1

2

3

45

6

78

9

1011

12

Mstl-tgpl

Rgpl-qspr

Jgn-grvm

Jgn-akprGpr-tkd

Gpr-mkpr

Mstl-dmtNrmt-nrmt

Nrmt-grm

Nrmt-trgNrmt-ktg

Nrmt-mlk

8295.

6292.

6269.

7243.5891.

12291.

18735.7175.

6071.

9221.5489.

10287.

271.

101.

269.

352.131.

483.

721.35.

71.

223.134.

699.

7.13

2.66

7.08

9.253.45

12.70

18.940.92

1.86

5.873.52

18.37

4.21

2.34

5.08

6.012.97

6.03

7.650.95

1.39

3.193.16

8.03

1.96

0.97

2.53

2.921.34

2.36

2.310.29

0.70

1.451.46

4.08

total 103260 3491. 91.75

TABLE: SUBSTATION DEMAND AND CAPACITY.

S.No.

Name of the

substation

Before improvements After improvements proposed

capacity

mva

Transformer

capacity

Demand

kva

Demand

existingkva

demand at

horizonyear kva

12

3

45

mustyalr pally

janagoan

ghanpurNARMETTA

6347.5

32

47.5

59300.46850.

27180.

45700.

46470.40781.

17916.

36793.33023.

59045.43701.

21291.

45248.47986.

Total demand 174983. 217271.

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CHAPTER 8

CONCLUSION

As discussed in earlier chapters load flow is most efficient and useful tool in Power

System planning and operation. Load flow on actual sub-transmission network in Warangal

district was studies necessary improvements were also suggested to improve the voltage

wherever they are beyond permissible limits in this project work.

The load flow can also be carried out for arriving network losses and remedial measures

for reducing losses may also be studied in future. Reduction of network losses is very important

in the prospect of any utility.

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2012 project

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