NAME: JAWAD ALI.

REG #: BSET01111037

SEMESTER: 6TH.

TECHNOLOGY: ELECTRICAL.

INDUSTRY: HUBCO POWER PLANT NWL.

DEPARTMENT OF TECHNOLOGY.

THE UNIVERSITY OF LAHORE.

DEDICATION

I dedicate this internship report to my parents. Because of their prayers and encouragement I have been able to complete this report.

Praise is to Allah, the most Gracious and Merciful, who blessed me with the knowledge and wisdom and enabled me to overcome this task. Heartiest gratitude to my parents without their continuous encouragement and love I could not have accomplished this task.

PREFACE :

Internship is the one step of a technical student's academic career. For a student of the Department of Technology industrial training is essential to complete understanding of the concepts, learned from formal education. There remains a huge gap between academic learning and the implementation of that hypothetical knowledge in the practical world of modern technology. Internship can compensate this wide gap as it brings opportunities for a student to comprehend the main trends of technology activities.

In compiling this report, I have intended to provide a synthesis of theoretical approaches and methods of implementing them in the world of technology. I have tried to discover the relationship between theoretical and practical type of knowledge. I have tried to bridge the gap between theoretical assumptions and practical necessities. During the entire course of our academic study we remain engaged in theoretical learning where the primary objective is academic success. A concise knowledge of the modern technology can only be attained through the pragmatic implementation of hypothetical ideas, which we learn from our academic activities.

With these objectives, I have made all possible efforts and the necessary investigations to submit this paper in an enlightened form in a very short time. I have tried my level best to eliminate errors from the paper. As I had to complete my internship within a short period of time so the study admits its limitations.

I visited the HUBCO POWER PLANT NAROWAL of Pakistan as a part of the internship program undertaken by the Department of Technology starting from 16 June 2014 to 08 August 2014 (8 Weeks).

Sincerely

( JAWAD ALI )BSET 01111037Department of Technology (Electrical)The University of Lahore.

ABSTRACT

This report contains the details of how power plant is operated, it’s machinery as well as description of them.

The first work is the verification and collection of the data of important electric equipment’s and system in power plant. This also includes the operation, devices used for the protecting and controlling devices used for the system.

This report describes my experience and suggestions which I want to give to HUBCO Power Plant Narowal.

TABLE OF CONTENT

1) Introduction of organization (Past, Present, Future).................. 1

2) Organization Chart.................................................................. 3

2) Departments of the Organization............................................ 4

3) Project Area of Training…....................................................... 7

4) Schedule of Internship........................................................... 16

5) Major Equipment’s Name Plate Data...................................... 18

6) Operation…………………………………………………………………

7) STG OPERATION……………………………………………………….

8) Engine Operation……………………………………………………….

9) Switchyard Instrument………………………………………………..

10) Power Transformer……………………………………………………

11) Alternator Protection Equipment………………………………….

12) Skills and Technique............................................................. 44

13) Role/Responsibilities of Internee.............................................45

14) Useful Points For new Internees........................................... 48

15) Suggestions........................................................................... 50

16) Conclusion............................................................................ 51

TNB REMACO PAKISTAN (PVT) LTD.

HUBCO POWER PLANT.

225MW COMBINED CYCLE DIESEL

HUBCO POWER PLANT NAROWAL.

INTODUCTION OF THE PLANT:

HUBCO Power plant Narowal Construction work began in 2008 and completed in 2010. The plant achieved its COD on 22 April 2011.The plant entered into an Equipment Supply Contract (ESC) with MAN Diesel & Turbo, Germany and Construction Contract (CC) with MAN Diesel Pakistan (Pvt) Ltd in April 2008 collectively called Engineering, Procurement and Construction (EPC) Contract.

The Owners Engineers were Mott MacDonald, Ireland.The O&M Contractor are TNB Remaco Pakistan (Pvt) Ltd a subsidiary of TNB Repair and Maintenance Sdn. Bhd, Malaysia. Narowal is a combine cycle power plant with net output of 214 MW. It consists of 11 diesel engines of 18.4 MW net output each plus a steam turbine of 16 MW. The fuel used is High Sulpher Furnace Oil (HSFO) supplied by Bakri Trading Company Pakistan (Pvt) Ltd.

PROJECT BRIEF

Gross Capacity at ISO 225MWPlant Output (Net) 215MWTechnology MAN Engines (18.4MW each)+1 Steam

turbine(16 MW) Combine CycleTerm of Agreement 15 yearNet Efficiency(Life Cycle)

50%

Customer WAPDA GAPCOConstruction Start Date April,2008Fuel provided by Bakari Trading Company (PVT) LTD.

VISION, MISSION

Vision Statement 

Enlighten the future through excellence, commitment, integrity and honesty.

Mission Statement 

To become leading power producer with synergy of corporate culture and values that respect community and all other stakeholders.

Quality Policy We work together as a team for implementation and continual improvement of total quality system in order to achieve satisfaction of our internal and external customers.

The Hub power station was one of the first and largest Independent

Power Producer (IPP) in Pakistan to be financed by the private sector in Southern Asia .The Hubco Narowal Power Plant (HNPP) has been constructed on 62 acres of land, 5 km off the Narowal Muridke Road, 15 km from Narowal and about 150 km North East of Lahore.

HUBCO Narowal Power Plant (HNPP) comprises of 11 generating sets based on MAN 18V48/60 Engine(It means 18 cylinders V-type each with 48 cm diameter of cylinder and 60 is

length of strock.), 11 Alborg Heat Recovery Steam Generators and one air cooled condensing Steam Turbine from Dresser Rand .

Each engine has generating capacity of 18.9 MW while the designed output of the Steam Turbine is 16.45 MW Interconnection with the NTDC system is via a 132 KV Switchyard of

HNPP having 4 overhead outgoing bays. The power is dispersed to NTDC grid system through:

Narowal Grid Station (12 km transmission) Baddomalhi – Narowal 132 kV circuit (2 km line)

The Operations and Maintenance (O&M) of HNPP is contracted out

to Tenaga National Berhad Repair and Maintenance Company (TNB REMACO) for a period of 5 years.

The Fuel Supply Agreement has been executed with Bakri Trading Company Pakistan (Pvt) Limited for a period of 25 years. The Complex has the storage capacity of 30 days of fuel consumption at full dispatch level.

ORGANIZATION CHART

DEPARTMENTS OF ORGANIZATION

There are many departments in HUBCO Power Plant.

The Main Departments Are .

MANAGEMENT DEPARTMENT

1. H.R DepartmentHuman resources is the set of individuals who make up the workforce of an organization, business sector, or economy.The HR Department of Century also conductsinterviews, training programs.

2. Finance DepartmentThe Finance department is responsible for organizing the financial and accounting affairs including the preparation and presentation of proper accounts, and the provision of financial information for managers. The main areas covered by the financial department include; book keeping procedures, providing management information, management of wages and raising of finance.

TECHNICAL DEPARTMENTTechnical Department Consist of Mechanical, Electrical , Decanting and Chemical Departments.

1. ElectricalThis department is responsible of all electrical ,maintenance all electrical equipment’sand also observers whole electrical system like switch yard and generators speed, powerfactor, winding temperature etc.Electrical have two sub departmentone is called Electrical maintenance and other one is called electrical operation department.

2. Mechanical

This departments is responsible of all the mechanical work in HUBCO to check the vibration of Engine and also observers whole mechanical system like working of engine, observe temperature of engine linear, header and also do the daily or routine maintenance mechanical department control of boiler etc. Mechanical have also two sub department one is called mechanical maintenance and other one is called mechanical operation department.

3. Chemical

This departments is responsible of all the chemical work in HUBCO to check the TDS in HT or LT water and check Sulpher in HFO also check dielectric strength of transformer oil.

4. Decanting

In HUBCO Power Plant this heavy fuel oil (HFO) (LFO) and Lube Oil is treated through different process to make it useful for the engine to generate the electricity. This process called DECANTING PROCESS. Heavy fuel oil (HFO) after suction from tanker in decanting station goes to the storage tanks for storage.

FIRE FIGHTING DEPARTMENT

A fire department provide "fire protection" or fire prevention services, and give fire safety advice and fit smoke alarms for members of the Industry. In HUBCO F.F Department gives training to all their employs and trainees how to react in the emergency and how to protect the fire victim area from fire.

HEALTH DEPARTMENT

This department gives medical facilities and first aid in case of any accident.

NAME PLATE DATA OF EQUIPMENTS:

Alternator used with Diesel Engine:

Alternator used with Steam Turbine :

MAN DIESEL ENGINE:

BOILERS:

Where volume in cubic meter, Pressure in bar and Temperature in centigrade.

STEAM TURBINE:

OPERATION:

There are 11 marine engine (18V/48/60B) rotate 11 generators, giving 18.9 MW each. An engine uses HFO as a fuel. After it uses HFO, its exhaust is of so high temperature that it can be used to convert water to steam. Exhaust converts the water into steam by Heat Recovery Steam Generation HRSG. This steam is then used to drive steam turbine which provides 16.2 MW. HRSG makes this process, combine cycle, hence called combine cycle diesel power plant.

Principle of engine

An engine is a mechanical device which acts as a prime mover to rotate the rooter of alternator to generate the electricity. It works on the principle of 4-strocks in which 4-strocks take place in each cylinder one after another .these 4-strocks are:

Intake Stroke Compression Stroke Power Stroke (combustion) Exhausts Stroke

MAIN COMPONENT OF ENGINE

There are many component of engine which are following:

I. LINER

Such a component of engine which is cylindrical cone in shape. Piston moves in it vertically. It is covered by head.

II. HEAD

Such a component of engine in which intakes and exhausting valves open and close. It covers the liner. This head is made of cost iron.

III. PISTON

Such a component which sucks the air and compressed it. This piston helps in combustion process.

There are three part of piston which is given bellow:

Crown Skirt Piston rings

IV. CRANK SHAFT

Such a shaft which derived by cam shaft through rocker arms head valve pistons etc. crank shaft is coupled with the alternator shaft and provide the mechanical energy of alternator shaft.

Types NoCompression ring 2Oil compression rings 1

V. CAM SHAFT

Such a shaft which is provide the mechanical power of rocker arm by push rods is called cam shaft. It is moved by crank shaft with the help of gear.

VI. HEAD VALVES

Such a component which moves back and forth and cause.The intakes the fresh air and exhausting of heat through head opening. There are two types of valves:

Intakes valves Exhausting valves

VII. ROCKER ARMS

Rocker arms located at upper side of engine, with its two arms .One side of each arm attached with cam shaft through pushing rods other sides attached with head valves. When cam shaft moves rocker arm attached with it also move and on the other side of rocker arm head valves which are attached on that side also move up and down .In the result of opening the hole of head and intake air and exhaust the heat possible.

VIII. COUNTER WEIGHT

It is installed on crank shaft .When piston hits the crank shaft and it rotates then counter weight helps in this rotation of crank shaft also spot it.

IX. MAIN BEARING

It is installed on the crank shaft. They provide the spot, control the vibration and move the crank shaft smoothly main bearing protect the shaft from damaging.

X. FLY WHEEL

Fly wheel are inserted at the end of crank shaft in between engine and alternator .it is a main part of engine which rotates the crank shaft by storing power during first stock and provides it to the crank shaft in

remaining the three stroke. It is very heavy in weight so it provides the inertia from rotation of crank shaft.

XI. TURBO CHARGER

Turbo charger instead on the front of engine speed of T.C is 19000 rpm. It performs two functions.

It sucks the fresh air from atmosphere and compress it .After compressing the air turbo charger sends it to the engine for combustion.

It exhausts the heat which produces during the combustion.

XII. CHARGE AIR COOLER

Charge air cooler is used to maintain the temperature of compressed air before sending it to the engine for the combustion air coming out of turbo charger has very high temperature then required for the combustion in the engine. That why we installed charge air cooler to reduce the temperature to a useable value .it is located under the turbo charger.

XIII. FUEL SUCTION PUMP

A suction pump is installed near the every liner of engine it sucks the HFO from the pipe lining which is supplying HFO to the engine and sends it to fuel injector. Then sprays this HFO on the piston in the liner for combustion in the form of sprinkles from fuel injector.

KEY SYSTEMSThe key systems of the plant include:

Fuel System Air System Cooling System of Engine Lubrication System of Engine Steam Handling System

Power System Dispatch System Control Room

These systems help to maintain the engines which drive the alternator which in return produce electricity. We will discuss these systems one by one.

FUEL SYSTEMIn HUBCO Power plant we are using heavy fuel oil (HFO) as a fuel for production of electricity. This heavy fuel oil (HFO) is treated through different process to make it useful for the engine to generate the electricity. These process are given bellow:

FUEL DECANTING PROCESS STORAGE OF FUEL FUEL TREATMENT HOUSE

1. FUEL DECANTING PROCESSIn Decanting station pumps using to unload fuel.These pumps drived by induction motor which sucks the heavy fuel oil (HFO) from tanker through a filter and valves. These are 8 in numbers which is installed in decanting station.

And these pumps transfer HFO in main Tank…

2. STORAGE OF FUEL

The storage tanks are Different types which are given bellow:

I. Main TankII. Buffer Tank

III. Day TankIV. Lube Oil TankV. Sludge Tank

VI. Oily Water Tank

Heavy fuel oil (HFO) is stored in Main Tank after suction from decanting process.

Buffer tank need of our daily requirement heavy fuel oil (HFO) is pumped from main tank to buffer tank through various pump with the help of valve installed in the line.

After purification in the fuel treatment house (FTH) the purified heavy fuel oil (HFO) goes to day tank for storage. Day tank stores the heavy fuel oil (HFO) daily consumed by engine.

Lube oil after suction from tanker goes to lube oil tanks first storage.

Sludge tank stores the sludge coming out of HFO separator after treatment from oily water treatment house in which oily water and sludge are separated.

Oily water tank stores the oily water coming out of oily water treatment plant and lube oil separator.

COOLING SYSTEM OF ENGINE It consists of LT water, HT water and the row water. LT and HT water are

actually the same form of water moving in the engine in a close cycle from heat exchanger to the back that the heat exchanged but the only difference between LT and HT is that of temperature value so called the low temperature and the high temperature.

1. LT WaterWith heat exchanger, the LT water start moving with its initial temperature range to 420 C to 480 C. It goes to charge the air cooler first to maintain the temperature of the compressed air to useable value. From charged air cooler, LT water moves to the lube oil cooler to cool down the lube oil to make it workable when this LT water comes out of the lube oil cooler. Its temperature crosses the value of 500 C which is the limiting value of LT Water. This water now becomes High temperature with temperature about 590 C.

2. HT WaterIt is the water coming out of the lube oil cooler with the temperature of 590 C. Initially as it moves in the internal part of the engine, the temperature goes on increasing. Before entering the liner of the engine, its temperature is 800 C to 840

C. In liner, it keeps the temperature of the liner walls to a limited value. It also saves the liner walls from expanding which occur often because of increase in temperature. After coming out of the liner, HT water has temperature of 900 C to 950 C. This high temperature water goes to heat exchanger where it exchanges the heat with row water and again becomes the LT water and the cycle continues.

3. Raw WaterIt absorbs the heat in the heat exchanger and its temperature increases to some extent. After this, it goes to cooling water for cooling purpose.

4. COOLING TOWERIt is the part of engine cooling system where raw water is cooled. A cooling tower is basically a closed room in which fans and sprinkles are installed.The raw water moves in spiral pipes on which sprinkles are sprinkling the water to cool the raw water. The raw water is cooled which is pumped down to heat exchanger. The sprinkled water is again pumped to the sprinkled pipes which are sprinkling. The air fans collect the stream from cooling tower and exhaust to atmosphere. These fans are driven by induction motors

LUBRICATION SYSTEM Lube oil from main tank is pumped to the engine for the cooling and

lubricating purpose in the engine. The temperature of lube oil increases so we send it to the heat exchanger through pumps. In heat exchanger the high temperatures lube oil it exchanges its heat with raw water and becomes cool. After exchanging heat the cool lube oil passes through auto filter section. Where it filtered and then sends it to engine.

Switch Yard System.

COMPONENTS OF SWITCHYARDBasic electrical components available in Switchyard are: Power Transformer, Reactors, Instrument Transformers (Current and Voltage/Potential Transformer), Disconnect Switches, Bushings, Surge Arresters, Standoff Insulators and earth switches. Some of these components look alike and hence are sometimes misused for one another, effect of which is catastrophic to the equipment, the entire electrical network and to the personnel. This is applicable to Standoff Insulators, Lightning Arresters and Bushings, but each of them possess unique characteristic, which this paper will expatiate. In view of this, discussion will be limited to these three components, and the station Operator and Infrared thermographs who have limited substation experience will be able to differentiate among these components. Each components located in the Switchyard.

1. MV ROOM

Many medium voltage (MV) indoor switchgear rooms exist worldwide. The complexity of these rooms varies considerably depending on location, function and technology adopted by the owner.

2. CONTROL ROOM

Control Room is actually a place which monitors and controls boilers, turbine, engine, alternator, transformer and switch yard, every part and components of the thermal power plant or any other plant. Different types of control panels and feeders are installed in the control room for a s a whole and individually control of the components of plants. In HUBCO control 11 control panels for 11 engines and the generators in turn. 7 Panels are installed for DC supply to the control room. 4 panels are installed for 4 power supply lines. 1 for KALA SHAH KAKO and 3 for NAROWAL. All this system is PLC based and controlled automatically by high technology computers and software. The control system performs following operations.

Maintains safe and efficient boiler operation. Monitors plant operational and emission data detects and responds to the

changing conditions with the regard to the maximizing plant safety and efficiency.

Overseas the operation of plant equipment and dispatch operators for local maintaining for safe operation.

Works with maintenance to troubleshoot the problems and ascertains possible cause.

Read meters and gauges or automatic recording devices at specified intervals to verify operating conditions.

Record data such as temperature of equipment, hours of operation, fuel consumed, temperature or pressure, water level, analysis of fuel gases, voltage load and generator balance.

STARTING AIR SYSTEM:

Staring air is necessary for the staring of engine initially. For this purpose there is a proper system, which provides compressed air. This system is called starting air system. According to this system the fresh air is taken from the environment and compressed to required pressure. This process takes place in the compressor room where the fresh air is sucked from the environment and sent to the compressors. Where it is compressed to 25-30 bar of pressure. This compressed air is then sent to the engine where it is provided to the liner of engine. It accumulates at the bottom of every liner of engine and provides initial push to the piston in upward direction. When the

engine gain the speed of about 120 rpm. The starting air supply is interrupted and working air supply is switched on which takes the engine to full speed e.g. 500rpm.

WORKING OF ENGINE

In engine, the main part is crank shaft which rotates itself, the other parts of the engine and the alternator itself. As the crank shaft moves, it also moves the cam shaft through push rod. Cam shaft on the other hand moves the head valves up and down. As the head valve moves up and down, the intake of air and exhaust of gases occur through the opening of the head. The air intake causes the combustion of the fuel by up and down movement of the piston. The piston is connected to the crank shaft. By this up and down movement of piston, the crank shaft rotates about its axis. The crank shaft in turn rotates the cam shaft and this process continues. As mentioned above, the crank shaft is also coupled with the rotor of the alternator through the fly wheel. 100 rotations of the crank shaft cause the rotation of the rotor of the alternator which in turn produces the electricity.

Alternator

Such a machine which converts a mechanical energy into electrical energy is called generator.

In HUBCO, 12 Alternators, 11 have connection type Ү, output power 23035KVA, 15KV, 500rpm, power factor 0.8, current 887amp, salient pole. Excitation system pilot 131vdc, 11.3Adc.

One Alternator ABB, connection type Ү, output power 18428KVA, 15KV, 1500rpm, power factor 0.8, current 703amp, salient pole. Excitation system pilot 123vdc, 10Adc.

STEAM HANDELING SYSTEM

This system of steam handling refers to the production of steam in the boiler and then utilization Of this steam in the turbine for production of electricity. The exhaust coming out of turbo charger of eleven engines goes to their respective boiler unit for conversion into steam. In boiler the heat (exhaust) coming out of engines with

temperature about 400 -450 degree to steam after passing through different components of boiler.

1. Boiler UnitBoiler is consisted of 4 parts named as LP evaporator. Economizer, HP evaporator and super heater. It is the boiler unit where actually the conversion of heat into steam takes place. The exhaust coming out of engine goes to the LP evaporator. At this stage it is to be noted that the boiler being used in HUBCO are water tube boiler in which water circulates in tubes heat is surrounding these tubes inside the boiler. This water is provided by boiler feed water tank, from the LP evaporator. The water in tube goes to economizer converts the water in tube into unsaturated steam. This unsaturated steam gains its proper value in HP evaporator unit where the actual unsaturated steam is produced. From HP evaporator this unsaturated steam drum inserted above the every boiler unit. This stream drum is partially filled with water and partially with unsaturated steam. The stream drum the moisture in the unsaturated steam is absorbed in water to some extent.This unsaturated steam not completely steam not completely dried goes to super heater for drying purpose. Now the stream coming out of super heater is pure steam and this steam is sent to steam header. The steam header is the storage tank where steam tank where steam coming out of boiler is stared and then fed to steam turbine.

2. Steam TurbineStream turbine being used in HUBCO is impulse steam turbine in which the

steam is passed through nozzle before hitting the rotor plates. The steam injecting out of nozzle has much velocity and pressure. It then hits the plates of rotor of turbine and causes its rotation. This rotor is coupled with generator through shaft and

causes the rotation of rotor of generator which gives electricity in turn the normal running speed of steam turbine rotor is 6000 rpm. The output speed is 1500rpm. The tripping speed is 6871/7177rpm. The power output of stream turbine is 16MW. The steam inlet pressure of steam turbine is 15Bar and the exhaust pressure is 0.01Bar. the steam inlet temperature of steam turbine is 350 degree.

Black Start Generator

 If all of the plant’s main generators are shut down, To provide a black start, power stations have small diesel generators, normally called the Black Start Diesel Generator (BSDG).

Type Sab 901 Year 2008 Rated power 375KVAMax Ambient 20 0C P.f 0.8 Frequency 50HzVoltage 400V Current 541A Speed 1500rpmPerformance class 82

LUBE OIL SYSTEM:

Lubricating oil ( Lube Oil ) of a Diesel Engine achieves two objectives:

It must cool and lubricate.

Among the other benefits yielded are

Reduced maintenance costs Maximized Engine life Maximized power output Low oil consumption.

Lube oil perform a number of important functions in the Diesel Engine:

Wear reduction of components such as bearings, pistons, piston rings and cylinder liners .

Reduction of Friction . Cooling of Piston . Corrosion prevention due to acids and moisture. Cleaning pistons and preventing sludge build-up on internal

surfaces. Keeping seals lubricated and controlling swelling to prevent

leakage due to seal failure.

Engine lube Oil consist of

Base Oil (typically75 - 83%)

Viscosity Modifier (5 - 8%) Additive Package (12 - 18%)

As the base oil alone cannot provide all of the lubricating oil functions required in modern engines, the additive package has evolved to play an increasingly important role in the oil lubrication.

The bellow Diagram describes the supply and storage of the lube Oil in Power Plant. Lube oil after suction from tanker goes to lube oil tanksfor storage and then circulated and filter for each eleven Engine in Plant. LO SEPARATOR UNIT is used for the Circulation and purification of the Lube Oil.

In a 4 stroke Diesel Engine the Lube Oil is supplied to the main bearings through drillings in the engine frame to the crankshaft main bearings. Drillings in the crankshaft then take the oil to the crankpin or bottom end bearings. The oil is then led up the connecting rod to the piston or gudgeon pin and from there to the piston cooling before returning to the crankcase.

Oil is also supplied to lubricate the rocker gear operating the inlet and

exhaust valves and to the camshaft & camshaft drive.

The oil then drains from the crankcase into the drain tank or sump. The oil in the drain tank is being constantly circulated through a centrifugal

purifier. This is to remove any water and products of combustion plus any foreign particles which may be in the oil.

The cylinder liner must be lubricated as well. This is so there will be a film of oil between the piston rings and the liner and also so that any acid produced by combustion of the fuel is neutralized by the oil and does not cause corrosion. The oil is led through drillings onto the liner surface where grooves distribute it circumferentially around the liner, and the piston rings spread it up and down the surface of the liner.

The below Diagram illustrate the Circulation of the Lube oil

The below Diagram explains the Lube Oil cooling Tower

LUBE OIL SEPRATOR:

EXAUST GAS SYSTEM :

In Exhaust gas heat recovery system exhaust gases of the internal combustion diesel engine are utilized to generate steam which is used for driving a turbine for an electric generator and the steam for miscellaneous uses in the Plant.

Four Basic HRSG Boiler Components

• Super heaters (gas to dry steam heat exchanger)

Super heater is one of HRSG components that serves to raise temperature of saturated steam to be superheated steam.

Superheated steam when used to perform work by way of expansion in the turbine will not condense, thus reducing the possibility of danger which is caused by back stroke caused by steam that condenses yet in time, so it will cause vacuum in undue area of expansion.

• Evaporators (gas to wet steam heat exchanger)

Evaporator is one of HRSG components which serve to convert water into saturated steam. Evaporator will heat water that falls from steam drum which still in liquid phase to form the saturated steam so it can be forwarded to super heater.

• Economizers (gas to water heat exchanger)

Economizer serves to heat feed water before it enters steam drum and evaporator. Furthermore the evaporation process can be easier by using high temperature flue gas of HRSG so increase the efficiency of HRSG because it can reduce heat loss in the Heat Recovery Steam Generator (HRSG). Water which enters evaporator is at high temperature so evaporator pipes are not easily damaged due to difference in temperature is not too high.

• Preheaters (gas to water heat exchanger)

Pre heater is one of HRSG components that serves as initial heater of water which is pumped from condenser before enter into feed water tanks. In the HRSG system, preheater serves to raise temperature before enter feed water tanks which later will be forwarded to economizer.

The Diagram of the Boiler illustrate the different Temperature ranges in

the different regions of the Boiler.

Super heaters

Evaporators

Economizers

Dearetor

COOLING SYSTEM :

The below Diagram describes the Cooling Water Supply.

The below Diagram describes the supply of Charge Air Cooling Water.

The below diagram describes the Cooling of the Nozzle.

The below diagram describes the cooling of the lube oil.

WATER TREATMENT PLANT (WTP):

Reverse osmosis (RO) is a water purification technology that uses a semipermeable membrane. This membrane technology is not properly a filtration method.

In reverse osmosis, an applied pressure is used to overcome osmotic pressure, a colligative property, that is driven by chemical potential, a thermodynamic parameter.

Reverse osmosis can remove many types of molecules and ions from solutions, and is used in both industrial processes and the production of potable water. The result is that the solute is retained on the pressurized side of the membrane and the pure solvent is allowed to pass to the other side. To be "selective", this membrane should not allow large molecules or ions through the pores (holes), but

should allow smaller components of the solution (such as the solvent) to pass freely.

Basic components of Reverse Osmosis System :

1. Cold Water Line Valve:Valve that fits onto the cold water supply line. The valve has a tube that attaches to the inlet side of the RO pre filter. This is the water source for the RO system.

2. Pre-Filter (s): Water from the cold water supply line enters the Reverse Osmosis Pre Filter first. There may be more than one pre-filter used in a Reverse Osmosis system. The most commonly used pre-filters are sediment filters. These are used to remove sand silt, dirt and other sediment. Additionally, carbon filters may be used to remove chlorine, which can have a negative effect on TFC (thin film composite) & TFM (thin film material) membranes. Carbon pre filters are not used if the RO system contains a CTA (cellulose tri-acetate) membrane.

3. Reverse Osmosis Membrane: The Reverse Osmosis Membrane is the heart of the system. The most commonly used is a spiral wound of which there are two options: the CTA (cellulose tri-acetate), which is chlorine tolerant, and the TFC/TFM (thin film composite/material), which is not chlorine tolerant.

4. Post filter (s): After the water leaves the RO storage tank, but before going to the RO faucet, the product water goes through the post filter (s). The post filter (s) is generally carbon (either in granular or carbon block form). Any remaining tastes and odors are removed from the product water by post filtration.

5. Automatic Shut Off Valve (SOV): To conserve water, the RO system has an automatic shutoff valve. When the storage tank is full (this may vary based upon the incoming water pressure) this valve stops any further water from entering the membrane, thereby stopping water production. By shutting off the flow this valve also stops water from flowing to the drain. Once water is drawn from the RO drinking water faucet, the pressure in the tank drops and the shut off valves opens, allowing water to flow to the membrane and waste water (water containing contaminants) to flow down the drain.

6. Check Valve: A check valve is located in the outlet end of the RO membrane housing. The check valve prevents the backward flow or product water from the RO storage tank. A backward flow could rupture the RO membrane.

7. Flow Restrictor: Water flow through the RO membrane is regulated by a flow control. There are many different styles of flow controls. This device maintains the flow rate required to obtain the highest quality drinking water (based on the gallon capacity of the membrane). It also helps maintain pressure on the inlet side of the membrane.

8. Storage Tank: The standard RO storage tank holds up to 2.5 gallons of water. A bladder inside the tank keeps water pressurized in the tank when it is full.

MAINTENANCE:

Operation & Maintenance (O&M) contracts cover all aspects and activities necessary to run your power plant in a safe and most economical manner. An O&M agreement will help you minimize your risks and maximize your profit.

Operation & Maintenance (O&M) service means that care about your assets and has major Objectives as below mention:

Operation (24/7)

Preventive Maintenance

Corrective Maintenance

Condition Monitoring

Benefits :

Meet increasingly demanding environmental and safety standards

Minimize lifecycle costs

Widen your competitive edge

Protect your assets and mitigate risks

General Maintenance Periods of Systems :

1.5 k Maintenance

3 k Maintenance

18 k Maintenance

SWITCH YARD:

The three-phase power goes to SWITCH YARD where power transformers are used to convert the generator's voltage (15 KV) up to extremely high voltages for long distance transmission (132 KV).

Switch yard includes:

Power transformer:

A transformer is an electrical device that transfers energy between two or more circuits through electromagnetic induction. In order to minimize the transmission losses power transformer is used by increasing voltage up to certain level i.e 132 KV.

The two main functions of a power transformer are to transfer electrical current from a source to a destination, and to regulate the voltage of that current before it reaches the intended destination. This is managed in the coil system of the device. The coils function as conductors, helping to maintain the current flow within a range that is considered acceptable. By managing the magnetic field fluctuation that takes place within the core of the power transformer, it is possible to control the voltage and change it in whatever manner is necessary before the current is delivered to houses or businesses.

The main parts of the transformer are as under :1. Oil Tank:This part of the transformer contains the assembly of the core and the winding which is immersed in insulation oil.

2. Radiator :This part is basically used for the cooling of transformer by the means of natural air.

3. Conservator:This is mainly used for the storage of extra insulation oil which is to overcome the requirement of the tank assembly system.

4. Air breather:This is used for the extraction of the moisture from the core of the transformers.

5. Temperature meter (O.T/W.T):These are used for taking the readings of O.T.I - Oil temperature Indicator and W.T.I - Winding Temperature Indicator.

6. Drain Valve:This is used for the Exhaust of the insulation oil during the maintenance of the Transformer.

7. Tap-changer:This is used for the tapping of the Transformer at different levels.

8. Pressure release Valve (P.R.V):This is used for the tripping purpose in the Transformers for the safety purpose.

9. Buchhloz Relay:This is used for the tripping purpose by the help air gap inbetween the switching circuit.

10. Primary and secondary winding:These are the two coils of the Transformer and the no. of turns depend upon the rating of the transformer. 

Bus Bars :

A conductor or an assembly of conductors for collecting electric currents and distributing them to the outer circuit.

Bus Bar SchemeIn HUBCO have double bus bar scheme,Indouble bus bar system two identical bus bars are used in such a way that any outgoing or incoming feeder can be taken from any of the bus.

Bus Coupler :

Two different bus sections of two different power transformers are connected by means of a bus coupler. The bus coupler becomes useful when one of the power transformers fails or a fault occurs in either of the bus sections.

Insulators:The overhead line conductors should be supported on the poles or towers in such a way that currents from conductors do not flow to earth through supports i.e., line conductors must be properly insulated from supports. This is achieved by securing line conductors to supports with the help of INSULATORS.The insulators provide necessary insulation between line conductors and supports and thus prevent any leakage current from conductors to earth.

Circuit Breaker & Relays:

A circuit breaker is an automatically operated electrical switch designed to protect an electrical current from damage caused by overload or short circuit. Its basic function is to detect a fault condition and, by interrupting continuity, to immediately discontinue electrical flow. The circuit breaker works along with the relays which give a tripping signal in case of any irregularity or the faults. The circuit breaker then opens to open the circuit such that other instruments of the system can be protected.

Isolators:

It is used to make sure that an electrical circuit can be completely de energized for service or maintenance. It also allowa the isolation of the apparatus such as circuit breakers transformers and transmission lines, for maintenance.

Current TransformersA current transformer (CT) is a measurement device designed to provide a current in its secondary coil proportional to the current flowing in its primary. Current transformers are commonly used in metering and protective relaying in the electrical power industry where they facilitate the safe measurement of large currents, often in the presence of high voltages. The current transformer safely isolates measurement and control circuitry from the high voltages typically present on the circuit being measured.Voltage transformers:Voltage transformers (VT) or potential transformers (PT) are another type of instrument transformer, used for metering and protection in high-voltage circuits. They are designed to present negligible load to the supply being measured and to have a precise voltage ratio to accurately step down high voltages so that metering and protective relay equipment can be operated at a lower potential. Typically the secondary of a voltage transformer is rated for 69 V or 120 V at rated primary voltage, to match the input ratings of protection relays.

Lightning Arrester:

A lighting arrester is a piece of equipment that is designed to protect electrical systems and components from damages that can be caused by surges of electricity. When a surge of electricity hits an electrical system, it attempts to equalize and dissipate itself, taking the most efficient routes. A lightning arrester provides a path of least resistance for doing this, routing the excess electricity

away from the system and into the ground where it can dissipate without doing any harm. The lighting resistor includes components attached to the electrical system with leads that reach the ground.

ALTERNATOR PROTECTIONS:

In a generating station the generator and transformer are the most expensive equipments and hence it is desirable to employ a protective system to isolate the faulty equipment as quickly as possible to keep the healthy section in normal operation and to ensure uninterruptable power supply.

The basic electrical quantities those are likely to change during abnormal fault conditions are current, voltage, phase angle and frequency . Protective relays utilizes one or more of these quantities to detect abnormal conditions in a power system.

Protective system cost is 4-5%of the total cost.

FAULT OCCUR IN GENERATOR: Unbalanced Loading.

Unbalanced loading arises from fault to earth or faults between phases on the circuits external to the alternator. Unbalanced current may burn the mechanical fixing of the rotor core or damage the field winding.Under normal operating condition, algebraic sum of three currents flowing through the relay is zero and relay does not operate. When unbalancing occurs, resultant current flows through the relay and relay trips the circuit breaker to disconnect the alternator from the system.

Stator Winding Faults.

Fault between phase and ground.Fault between phases.Inter-turn faults involving turns of same phase winding.

Differential Protection:It provides protection against phase to phase and phase to ground current at two ends of the protected sections are compared. Under normal operating conditions, these currents are equal, hence no current flows through the relay.

When a fault occurs in the protected zone, currents at two ends of the CT becomes unequal. Differential current flowing the the relay isolates the protected section from the system .

LIMITATIONIt is impossible to provide protection to the whole winding when neutral earthing resistance is used. It protects only 85% of the winding.

Failure of Field

The chances of field failure of alternators are undoubtedly very rare. Even if it does occur, no immediate damage will be caused by permitting the alternator to run without a field for a short period. In this case the alternator can be disconnected manually. So there is no need of automatic protection.

Over-currentIt occurs mainly due to partial breakdown of winding insulation or due to overload on the supply system. Over current protection for alternator is considered unnecessary because of the following reasons: As the modern alternators have considerably high values of internal impedance, these will stand a complete short circuit at their terminals for sufficient time without serious overheating.

On the occurrence of an overload, the alternators can be disconnected manually.Over-speed

The chief cause of over speed is the sudden loss of all or the part of load on the alternator. Centrifugal devices mounted on their driving shafts trip the main valve of the prime mover when a dangerous overs peed occurs.

Over-voltage

The field excitation system of modern alternators is so designed that over voltage conditions at normal running speed can’t occur.However, overvoltage in an alternator occurs when speed of prime mover increases due to sudden loss of alternator load.Usually control governers are provided which continuously checks the speed and prevents the over speed.

SKILL AND TECHNIQUE

I have learnt many techniques during my internship but my mostly focus was to learn complete system of power plant. I learn different system in power plant like , heat recovery system, generator system, cooling system, starting and shut down engine, fuel oil system, lube oil system, dispatch system. Control room engineer teach us about this system.

After learn some system they give me some home assignment (presentation at combine cycle diesel power plant and lube oil system working etc) to check my ability of learning. I complete my all assignments with full of devotion and satisfied my senior engineer. Basic skills are IR test, temperature sensor test which is detailed below.

1. IR test of Alternator

The insulation resistance and polarization index tests of an electric generator has been regarded as a useful tool in evaluating its windings for buildup of dirt or moisture., deterioration of the insulation, fitness for high potential tests and suitability for further operation. The IR test measures the resistance of the electrical insulation between the copper conductors and the core of the stator or rotor. Ideally the value of this resistance is infinite since the purpose of the insulation is to block current flow between the copper and the core. But in practice, it is not possible. However, the resistance should have a high value to avoid any appreciable leakage current. Lower value of IR indicates that the insulation has been deteriorated. PI is a variation of the IR test. It is the ratio of IR measured after voltage has been applied for 10 minutes (R10) to the IR

measured after one minute (R1), i.e.

PI = R10/R1

Low value of PI indicates that the winding may have been contaminated with oil, dirt etc or absorbed moistures. In the test, a relatively high DC voltage is applied between the copper conductor and the stator or rotor core usually between the winding and ground as the machine core &body is grounded).

2 TEMPERATE SENSOR TEST

Using two way to check the temperature sensors pt100 and thermocouple.Details are given below.

1. HEATER OIL BATH

It is used to calibrate and testing of temperature switches which are used in industry.

TEMPERATURE SWITCH:

The figure shown below is the temperature switch that can sense the temperature of fluid or water or oil have set points and consist of limit switches that can change the contact of switch when desire temperature achieved.

2. Process Calibrator

Temperature measurements with PT 100 elements have proven to be very robust and reliable. These sensors are very rarely replaced due to insufficient calibration results.

First of all sensor heated by using oil bath, then temperature sensor output check using process calibrator and give signal to PLC.

RESPONSIBILITIES OF INTERNEE

Be Punctual

Be Civilize

Use Good Language with all your seniors and juniors.

Be Ethical in all your Behaviors.

Accept and Obey the all Rule and Regulations of your organization

Before performing any Practical First have sufficient knowledge of it.

First Learn proper use of Tools and Equipment’s.

Call every Tool with it Specific proper name.

During Performing practical put all your concentration on your work.

Wear all Safety equipment in working area e.g. Ear Muffs, helmets,

Glovesetc.

Take care of your safety and Environment safety.

Never go in Restricted Area.

First take permission from your seniors to visit the industry.

SUGESTION AND RECOMMENDATION

1. INCREASE THE EFFICIENCY OF TRANSFORMERS

TO PREVENT YOUR SYSTEM FROM DISSOLVE GASSES THEY SHOULD INCREASE VALUE OF TRANSFORMER.

2. REMOVING MOISTURE IN SUPER-HEATED STEAM

THEY SHOULD MAKE A SAFE DISTANCE BETWEEN PIPES USED FOR SUPER HEATER AND EVAPORATOR IN STEAM DRUM.

3. SAFETY OF INTERNEE

PROVIDE PPS TO INTERNS FOR SAFETY.

PROVIDE SAFETY SHOES TO INTERNS FOR SAFETY.

PROVIDE SAFETY HELMET TO INTERNS FOR SAFETY.

PROVIDE EAR PROTECTOR TO INTERNS FOR SAFETY.

4. TRANSPORT FACILITY

PROVIDE TRANSPORT TO INTERNS.

5. SCHEDULE

PROVIDE INTERNSHIP SCHEDULE.

6. GOOD BEHAVIOR

DO NOT BURN BRIDGES AND BEHAVE GOOD WITH INTERNS.

CONSIDER INTERNS AS STUDENTS.

MAKE POSSIBLE LEARNING FOR INTERNS.

CONCLUSION

On the whole, this internship was a useful experience. I have gained new knowledge and met many new people. I got insight into professional practice. I learned the different facts of working within a company.

The internship was also good to find out what are my strengths and weaknesses. This helped me to define what skills and knowledge I have to improve in the coming time. This internship was definitely beneficial for me.