Industrial training report (GENCO-iii) by ( Engr. GHIAS-UD-DIN)

INDUSTRIAL TRAINING REPORT
THERMAL POWER PLANT
Gas turbine, Steam power & Central workshop
NOTHERN POWER GENERATION COMPAMY
LIMITED (GENCO-III), FAISALABAD.
SUBMITTED BY
GHIAS-UD-DIN
BSc ELECTRICAL ENGINEERING TECHNOLOGY
Session 2012-2016
2012-GCUF-01180
Roll no 1466
Training Report Period
15-02-16 to 24-05-16
DEPARTMENT OF ELECTRICAL ENGIEERING
GOVERNMENT COLLEGE UNIVERISITY
FAISALABAD

Industrial Training Report 2016
GHIAS-UD-DIN
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Dedication
I dedicate my dissertation work to my Family, thanks for their endless love, sacrifice,
prayers, supports and advices. I also dedicate this dissertation to my many friends and
class mates who have supported me throughout the internship. I will always
appreciate all they have done, especially Sir Maqbool, Sir Inam waris, Sir Muhammad
monas who Developed technology skills in me. I dedicate this work and give special
thanks to my University Teachers and HOD Engr. Ibrahim Khan.

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Acknowledgement
First of all I thanks to the Almighty ‘’ALLAH” who blessed me with courage and
made my efforts faithful, who best owed upon me with potential and ability to
contribute a little material to existing knowledge.
I pray all the tributes to the Holly Prophet Hazrat MUHAMMAD (S.A.W) who
enlightened our conscious, who is Torch of guidance and knowledge for humanity, all
and every respect is for the Holly Prophet Hazrat MUHAMMAD (S.A.W) who
enables us to recognize our creator.
I want to thanks the Chief Engineer (Thermal), Northern Power Generation Company
Limited (NPGCL) GENCO III, Faisalabad Mr. Sohail, Resident Engineer GTPS
Faisalabad, Resident Engineer Steam Power Plant Faisalabad, Resident Engineer
CGTM Workshop Faisalabad, Mr. Akbar, Assist. Director for their kind cooperation
during internship period. And Mr. Maqbool, Mr. Inam waris, Mr. M.Monas to
provided me the practical knowledge of the power plant, without their guidance and
help I could not completed my internship. I also like to thanks other Engineers and
staff of GENCO III (NPGCL) for their cooperation with me.
I would like to express my best regards to my academic coordinator, Professors,
Lecturers of Electrical Engineering Department, Govt. College University, Faisalabad
without of their guidance, I would not been able to complete my internship report
properly. Finally i want to thanks my Head of Department , Engr. M. Ibrahim khan.
I also want to thanks my group fellows Mr. Asad Ali, Mr. M.Waqar Arshad, Mr.
M.Usama Baig, Mr. Umer Virk, Mr. Zafer Iqbal, Mr. Mudasar and Mr. Mubasher to
share their knowledge and information with me and help me during the internship
period.
Signature of Student
Ghias-ud-din (1466)

GHIAS-UD-DIN
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Training Certificate

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CERTIFICATE
I hereby certify that I have completed the Fourteen weeks Training in
partial fulfillment of the requirements for the award of BSc
ELECTRICAL ENGINEERING TECHNOLOGY. I did my training
in Nothern Power Genration Company Limited (GENCO-III), Faisalabad.
from 15-02-16 to 24-05-16.
The matter presented in this report has not been submitted by me for the
award of any other degree elsewhere.
Signature of Student
Ghias ud din (1466)
Examined by:
Engr. Rehan Liyaqat
INCHARGE/HOD
Engr. M.Ibrahim Khan
Electrical Engineering Department

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TABLE OF CONTENTS
Acknowledgement ………………………………………………………………….04
Training certificate …………………………………………………………………05
Table of Contents …………………………………………………………………...06
Chapter 1: Introduction ……………………………………………………………10
1.1 Industrial Background ………...…………………………………………………10
1.2 Products of Industry ……………………...……………………………………...10
1.3 Unit wise detail …………………………………...……………………………...10
1.4 Capacity ……………………………………………...…………………………..11
1.5 Company SWOT analyses ………………………………………...……………..11
Chapter 2: Parts of G.T Unit ………………………………………………………12
2.1 Machines Installed in the G.T. Plant …………………………………………….12
2.2 Main Parts ………………………………………..………………………………12
Chapter 3: Fuel ……………………………………………………………………..13
3.1 Fuel types ……………..…………………………………………………………13
Chapter 4: Air filter ………..………………………………………………………14
4.1 Inlet/outlet air Filter ………………………………………...……………………14
Chapter 5: Combustion chamber …………………………………………………15
5.1 Compressor ………………………………………………………………………15
5.2 Combustion chamber ……………………………………….……………………15
5.3 Liner ………………………………………………..……………………………16
5.4 Fish tail ……………………………………………………………..……………16
Chapter 6: Turbine …………………………………………………………...……17
6.1 Definition ………………………………………………………………………...17
6.2 Types ………………………………….…………………………………………17
6.3 Turbine start process …………………….………………………………………18
6.4 Process ……………………………………………….……..……………………18
Chapter 7: Generator ……………………………………………...………………19
7.1 Definition ……………………………...…………………………………………19
7.2 Parts of Generator ………………..………………………………………………19

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Chapter 8: Synchronize ……………………………………………………………20
8.1 Definition …………………...…………………………………………………20
8.2 Synchronization requirement ….………………………………………………20
Chapter 9: Combine cycle plant …………………………………………………...21
9.1 Working principle …………………………………………………………..…21
Chapter 10: Switchyard ……………………………………………………………22
10.1 Introduction …………………….………………………………………………22
10.2 Components & Devices used ..…………………………………………………22
10.2.1 Bus-bar ………………………………….……………………………………22
10.2.2 Bus Coupler ……………………………………..……………………………23
10.2.3 Feeder …………………………………………………………...……………23
10.2.4 CT/PT (Current and potential transformer) …..………………………………23
10.2..8 Power Transformer ……………………………..……………………………25
10.3 Parts of Transformer ……………………………………………………………26
10.4 Cooling system …………………………………………………………………26
10.5 Bucholz relay …………………………………………………………...………27
10.6 Relay ……………………………………………………………………………27
10.6.1 Relays types ……………………………..……………………………………27
10.6.2 Relay’s working ……………………………...………………………………27
Chapter 11: STEAM POWER PLANT ……………………...……………………28
11.1 Definition …………………………………………………………………….…28
11.2 Line diagram of Steam Power Plant ……………………………………………28
11.3 Basic parts of steam power plant ……………………………………………….28
11.3.1 Boiler …………………………………………………………………………28
11.3.1.1 Types of Boiler …………………………..…………………………………29
11.3.1.1.a Water Tube Boiler ……………..…………………………………………29
11.3.1.1.b Fire Tube Boiler ……………….…………………………………………29
11.4 Parts of Boiler …………………………………………………………………..30
11.4.1 Boiler drum …………………………………………...………………………30
11.4.2 Boiler furnace ………………………………………...………………………31
11.4.3 Burners ……………………………………………………….………………32
11.4.4 Super Heaters …………………………………………...……………………32
11.4.5 Re-heaters …………………………………………….………………………33
11.4.6 Boiler Water Tubes …………………………………..………………………33
11.4.7 Air pre-heater ………………………...………………………………………34
11.4.8 Forced Draught Fan …………………………………………….…………….34
11.4.9 Chimney / Stack ……………………………………………………………...34
11.4.10 Boiler Safety Valves ………………………………………………………...35
11.5 TURBINE ……………………………………………………………………....35
11.5.1 HP (High Pressure) Turbine ....……………………………………………….35
11.5.2 LP (Low Pressure) Turbine …………………………………………………..35
11.5.3 Specification of the steam turbine ……………………………………………36
11.6 DC Supply ……………………………………………………………………...36

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11.6.1 Importance of DC supply .………………………………………………….36
11.6.2 Different parts of DC supply ….……………………………………………36
11.7 Use of battery in power station ….……………………………………………37
Chapter 12: Cooling tower .………...……………………………………………...37
12.1 Definition ………………………………………………………………………37
12.2 Fan blades ………………………………………………………………………37
Chapter 13:CENTRAL G.T MAINTENANCE WORKSHOP …………………38
13.1 Workshop’s History …………...……………………………….…………….38
13.2 Maintenance workshops ……………………………………….……………..38
13.3 Cleaning shop ………………………………………………….……………..38
13.4 NDT shop …………………………………………………….………………39
13.5 Welding shop ………………………………………………………………...39
13.6 Grainding shop …………………………………….…………………………41
13.7 Bering re-metalling shop …………………………………….……………….42
13.8 Heat treatment shop ………………………………………………….……….43
13.9 Balancing shop ………………………………………………………….……43
13.10 Electrical Shop …………………………………………………………….44
13.11 Machine shop………………………………………………………………44
Skill attained ………………………………………………………………………..46
Recommendations ...………………………………………………………………..47
Abbreviations ...……………………………………………………………………..48

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CHAPTER 1- INTRODUCTION
1.1 Industrial Background
Northern Power Generation Company limited the largest generation company. Which
is worked in Muzzaffarghar (Genco-i), Multan (Genco-ii) And Faisalabad (Genco-iii).
The company produces electricity with thermal power. The power plant is establish in
1974 by AEG west German Company.
1.2 Products of Industry
Genco-iii is the bypass power plant. The power plant produces electricity by using the
natural gas/ HS Diesel, Furnace oil And exact steam.
1.3 Unit wise detail
SPS Faisalabad
UNIT
NAME
TYPE Date of
installing
Installed
Capacity
(MW)
Dependable
Capacity
(MW)
Fuel
Unit no 01 Steam
Turbine
11.06.1967 66 50 RFO/GAS
Unit no 02 Steam
Turbine
15.11.1967 66 50 RFO/GAS
GTPS Faisalabad
Unit
Name
Type Date of
installing
Installed
Capacity
(MW)
Dependable
Capacity
(MW)
Fuel
GT-1 Gas
Turbine
09.03.1975 25 21 GAS/HSD
GT-2 Gas
Turbine
10.03.1975 25 21 GAS/HSD
GT-3 Gas
Turbine
04.05.1975 25 21 GAS/HSD
GT-4 Gas 06.03.1975 25 21 GAS/HSD

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Turbine
GT-5 Gas
Turbine
31.07.1975 25 23 GAS/HSD
GT-6 Gas
Turbine
05.07.1975 25 23 GAS/HSD
GT-7 Gas
Turbine
10.07.1975 25 23 GAS/HSD
GT-8 Gas
Turbine
14.11.1975 25 23 GAS/HSD
GT-9 Combine
Cycle
28.12.1994 47 42 GAS/HSD
1.4 Capacity
The capacity of Genco-iii power plant is 247 MW (Gas turbine 200MW and Combine
Cycle 47 MW). And the SPS has two unit 132MW (66*2MW).
Turbine = 5000 RPM
Generator = 3000 RPM
Turbine = 25 M Watt 1*8
Combine cycle= 47 M Watt
1.5 Company SWOT analyses
STRENGTHS
 The largest generation company.
 Availability of land for capital expansion.
 Power Plant are located in the load centers.
 Highly qualified skilled Engineers and labor available.
 Provision of Dual Fuel firing.
 Road and Rail track facilities for furnace oil supply.

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CHAPTER 2- Parts of G.T Unit
2.1 Machines Installed in the G.T. Plant
Gas turbine power plant
2.2 Main Parts
 Daily oil tank
 Inlet/outlet air Filter
 Compressor
 Combustion Chamber
 Turbine
 Generator
 Combine Cycle
 Transformer
Combine cycle Inlet FilterTurbine Daily oil tankGenerator

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CHAPTER 3- FUEL
3.1 Fuel types
(1) HSD oil (2) GAS
3.1.1 HSD OIL
The High speed Diesel (HSD) is used to operate the system. The daily tank used to
store the oil which is used in day. Its capacity is 5500 liters. Two filters are used to
purification the oil. And The A.C motor is used to flow the oil and D.C motor is used
as backup.
3.1.2 GAS
The Natural Gas is mostly used in system. The gas pressure should be 14-16kb. The
gas is mostly used due to cheap in price as compare to HSD.

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CHAPTER 4- AIR FILTER
4.1 Inlet/outlet air Filter
The Inlet/outlet Filter are specially developed for gas turbine compressors. The filters
are built to protect the gas turbine against pollution in the air and resist moisture. It
consists of 416 approx. and their use full life is around 2 years

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CHAPTER 5- COMBUSTION CHAMBER
5.1 Compressor
This compressor intakes air through air inlet filters and send it into combustion
chamber. The air passes through different stages and attains pressure & temperature.
On every stage the temp and Pressure rises with a specific ratio. Compressor has 16
stages and its comparison ratio is 1-10 bars. Thus if the inlet pressure is 1 bar then the
compressor outlet pressure will be 10 bar and temperature rises up to 450 ⁰C.
5.2 Combustion chamber
A combustor chamber is an area of gas turbine where combustion takes place. In the
combustion chamber the compressed air mixed with fuel and the mixture is burned.
Combustion chamber is a part of turbine where energy converts from chemical energy
into heat energy. Some gas turbines have 14 combustors and hot gases are passing
through each combustor and enter into turbine.

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5.3 Liner
The liners are used to control the fire in system. 8-10 liner used in each gas turbine.
The air is mixed with flame and burns the gasses.
5.4 Fish tail
The fish tail shape pipes are used to putt the hot gasses at the turbine to rotation.

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CHAPTER 6- TURBINE
6.1 Definition
A turbine is a machine that is designed to convert the chemical/fuel energy into
mechanical power. The 5100 rpm turbine used in the gas turbine.
6.2 Types
1. Impulse Turbine
2. Reactive Turbine
Parts of Gas Turbine
 Filter House
 Axial Flow Compressor
 Combustion Chamber
 Gas Turbine

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6.3 Turbine start process
Turbine start in different process
Check Ready to start  Start  Sequence in progress  Auxiliarien ON
6.4 Process
The first 20% rotation of turbine is complete by the exciter generator or 350MW
motor. 20% to 60% of speed the flame accour which burn the furnace oil and the hot
gasses are produced to rotate the generator shaft.

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CHAPTER 7- GENERATOR
7.1 Definition
Generator is a machine which converted the mechanical energy in to the electrical
energy. The generator shaft is couple with turbine. The generator is 32 MVA. And
generate 11kv with 50 Hz frequency.
7.2 Parts of Generator:
 Rotor & Stator
 Casing & Bearing
 Exciter
Rotor
This is rotating part of generator and field winding in nested upon it, this is coupled
with turbine shaft.
Stator
This is stationary part of generator and stator winding is nested in it, this is coupled
through bus bar to system.
Frame
Generator frame contain rotor winding, stator winding and bearing. Generator frame
restrict the outer element to get into the generator casing. This also prevents from
expulsion of hydrogen and provides heavy support.
Bearing
The bearing share load of generator rotor and prevent from excess radial movement.
Exciter
This device supplies DC current to rotor, so that the generator can work on the law of
electromagnetic.

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CHAPTER 8- SYNCHRONIZE
8.1 Definition
When two different electrical systems are coupled together it is called synchronization
or to connect the generator with system.
8.2 Synchronization requirement
There are three main aspects during synchronization
1. Generator and system voltage should be same.
2. Generator and system frequency should be same.
3. Generator and system phase angle should be equal.
For synchronize Automatic Voltage Regulator used for excitation.
Phase sequence, Voltage Level and frequency should same for synchronize.

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CHAPTER 9- COMBINE CYCLE PLANT
9.1 Working principle:
A combine cycle power plant is at the end of the gas turbine. This plant produce 50%
more electricity from the same fuel with the exact of 480’C, this exact is used into
combine cycle, and get 47 MW power in GTPS. The waste heat from the gas turbine
is used in boiler to produce the steam and this steam to rotate the steam turbine, the
turbine is coupled with generator shaft.

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CHAPTER 10- SWITCHYARD
10.1 Introduction:
Switchyard means collection of electrical equipment where high voltage electricity is
switched using of various component. Electrical switchyards are usually part of a
substation where electricity is transformed from one voltage to another for the
transmission or distribution.
Switchyard provides the facilities for switching, Protection & control of electric
power.
A switchyard is essentially a hub for electrical power sources. For instance, a
switchyard will exist at a generating station to coordinate the exchange of power
between the generators and the transmission lines in the area. A switchyard will also
exist when high voltage lines need to be converted to lower voltage for distribution
to consumers. The function of electrical switch yard is to deliver the generated power
from power plant at desired voltage level to the nearest grid. In Another way we can
say simply switching the received power supply from various generating stations to
various locations with respect to their requirement. Therefore a switchyard will
contain; current carrying conductors, grounding wires and switches, transformers,
disconnects, isolators, remotely controlled arc snuffing breakers, metering devices,
etc.
10.2 Components & Devices used in Switchyard
 Bus bar
 Bus couplers
 Feeder
 CT & PT
 Power transformer
 Isolators
 Breakers
 Lightening arrestor
10.2.1 Bus-bar
These are connecting bar which are connected to various local and distribution feeders
and also intact with supply sources. OR Those conductors that receive source supply

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and distribute to different lines.
10.2.2 Bus Coupler
Double bus scheme, where two bus bars are installed a provision of bus coupler has
been provided. Therein a bus coupling circuit breaker with two isolators is called bus
coupler. Its prime function is to substantiate the supply on any bus bar without
disconnecting with system.
10.2.3 Feeder
The feeder is used to connect the electricity to consumer. This has vital role is power
system
10.2.4 CT/PT (Current and potential transformer)
These are also called instrument transformer. These are used to measure voltage and
current of different high voltage lines.
CT is a type of instrument transformer that is used in power system for measurement,
detection, protection the system. Current transformers are used extensively for
measuring current and monitoring the operation of the power grid. Current
transformers, together with voltage transformers (VT) (potential transformers (PT)),
are known as instrument transformers.it is a device used to measure large current by
scaling large primary current to a smaller , easy to measure, secondary current.

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Current or voltage instrument transformers are necessary for isolating the protection,
control and measurement equipment from the high voltages of a power system, and
for supplying the equipment with the appropriate values of current and voltage -
generally these are 1A or 5Α for the current coils, and 120 V for the voltage coils.

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10.2.5 Isolator
Isolators are used in electrical substations to allow isolation of apparatus
such as circuit breakers and transformers, and transmission lines, for
maintenance. Often the isolation switch is not intended for normal
control of the circuit and is used only for isolation. This can be termed
as off load switch Isolator is also capable of switching with the charging
current and also breaks the bus transfer current which is its functional
requirement.
An isolator switch is used to make sure that an electrical circuit can be
completely de-energized for service or maintenance.
10.2.6 Breaker
A circuit breaker is an automatically-operated electrical switch designed to protect an
electrical circuit from damage caused by overload or short circuit. Its function is to
interrupt continuity, to immediately discontinue electrical flow. In switchyard High
Capacity Circuit Breakers are used. It works on on-load.
A circuit breaker is a piece of equipment which can
I. Make or break a circuit either manually or by remote control under normal
condition.
II. Break a circuit automatically under fault conditions
III. Make a circuit either manually or by remote control under fault condition
10.2.7 Lightening arrestor
A lightening arrester is a device to protect electrical equipment
from over-voltage transients caused by external (lightning) or
internal (switching) events. Also called a surge protection device
(SPD) or transient voltage surge suppressor (TVSS) .
A lightning arrester is a device used on electrical power systems
and telecommunication systems to protect the insulation and
conductors of the system from the damaging effects of lightning.
The typical lightning arrester has a high-voltage terminal and a
ground terminal. When a lightning surge (or switching surge,
which is very similar) travels along the power line to the arrester,
the current from the surge is diverted through the arrestor, in most
cases to earth.
10.2.8 Power Transformer
This is stationary device even though no part of this device is Rotating. This operates
on the law of mutual induction. According to Faraday’s law if current is supplied in

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one coil the due to mutual Induction the supply will automatically enters into second
coil. Transformer work on this law and transform the current from high to Low
voltage or low to high voltage. The coil in which the current is supplied called
“Primary coil” and the receiving coil is called “Secondary coil”. The transformer can
be step up or step down. Transformers are used to reduce of improve the generator
voltage which is further supplied to system.
10.3 Parts of Transformer
Parts of Transformer
 Conservation tank
 Breather
 Primary winding
 Secondary winding
 LT terminal
 HT terminal
 Iron core
 Transformer cover
 Oil cooler
 Cooling fans
 Tap changer
10.4 Cooling system
 ON,AN (oil natural, air natural)
 ON,AF (oil natural, air forced)
 OF,AF (Oil force, air forced)

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 OF,AN (Oil force air natural
10.5 Bucholz relay
This relay has been installed in between conservator tank and transformer. This
prevent the transformer from every of kind of internal fault which can be occur by
short circuiting winding and core terminals. Due to short circuit the oil gets
overheated and resultantly gasification will occur. These gases travels to the
conservative tank thereby Bucholz relay has been placed. The mercury switches will
get operated which subsequently operate the primary and secondary circuit breaker
and generator breaker got opened. It is also called gas operated relay.
10.6 Relay
The relays are use for productions of the system
10.6.1 Relays types
The two type of relays are used .
1.Fix time relay
2.Inverse time relay
10.6.2 Relay’s working
The working of the relay depend on the signal of P.T and C.T, the D.C supply and the
time period. The relay should be healthy to product the system.
 Relay using in R.E
 Under excitation relay
 Reverse power relay
 Differential current relay
 Generator over current relay
 Condenser over current relay
 Negative phase sequence
 Earth fault/220 volt D.C fail
 Generator winding temp high

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CHAPTER 11- STEAM POWER PLANT
11.1 Definition
A thermal power station is a power plant in which the prime mover is steam driven.
Water is heated, turns into steam and spins a steam turbine which either drives an
electrical generator.
11.2 Line diagram of Steam Power Plant
11.3 Basic parts of steam power plant
 BOILER
 TURBINE
 GENERATOR
11.3.1 BOILER
A boiler or steam generator is a device used to produce steam by applying heat energy
to water. Thus, when heat is applied it produces steam and pressure in close vessel.

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11.3.1.1 Types of Boiler
 Water tube boiler
 Fire tube boiler
11.3.1.1.a Water Tube Boiler
In water tube boiler, boiler feed water flows through the tubes and enters the boiler
drum. The circulated water is heated by the combustion gases and converted into
steam at the vapor space in the drum. These boilers are selected when the steam
demand as well as steam pressure requirements are high.
11.3.1.1.b Fire Tube Boiler
In fire tube boiler, hot gases pass through the tubes and boiler feed water in the shell
side is converted into steam. Fire tube boilers are generally used for relatively small
steam capacities and low to medium steam pressures.

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11.4 PARTS OF BOILER
1. Boiler Drum
2. Boiler Furnace
3. Super Heaters
4. Re-heaters
5. Boiler water tubes
6. Air pre heater
7. F.D Fan
8. Chimney
9. Boiler safety valves
10. Down comers
11. Lower header / Drum
11.4.1 BOILER DRUM
Boiler drum receives feed water from economizer. This water goes through the drum
to down comers and thereafter it enters into up riser tubes. The up riser tubes generate
saturated steam which comes back into boiler drum and thereafter the steam goes to
different super heaters.

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Duties of Boiler Drum
1. Receives feed water
2. Store feed water
3. Distributes the water
4. Contains pressure
5. Receive steam water mixture
6. Provides outlet to saturated steam
7. It performs the process of separation and steam purification
8. At higher pressure with the aid of baffles and other devices.
11.4.2 BOILER FURNACE
The furnace is the place where burning process with a mixture of fuel and air takes
place. This provides space during burning. This also prevents the heat loss during fire
because this is a sealed compartment. Furnace disburses heat to up riser tubes which
converts water into steam. This also prevents to enter cold air into furnace.
The furnace design should be like that which prevent heat losses.

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11.4.3 Burners
Burner is a device, which helps to ignite fuel with the help of air. This device is used
for proper firing. Burner is a prime source to set right the fuel and air mixture,
pressure and firing location. Burner is also called boiler operating parameter due to its
importance for calculating boiler efficiency.
Properties of Burner
 With the help of burner fuel burns completely.
 Easy to operate.
 Maintain fire arc’s direction, so that at heat utilized within furnace.
 It makes proper mixture of air and fuel
11.4.4 Super Heaters
It is boiler auxiliary designed to superheat the saturated steam to a specified
temperature. It may reach up to 540 C.
 Duties of Super Heater
1. It increases the temp. of saturated steam.
2. It is used to dry the steam
3. It provides an outlet to superheated steam towards the steam turbine.
Super heater consists of bundle of tubes from which saturated steam passes. This wet
steam gets more heat to convert into super-heated steam. Super heaters are installed in
all three zones of boiler.
1. Radiant Super heater
2. Platen Super heater

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3. Convective Super heater
The temperature of superheated steam is around 400 to 595 ⁰C. Usually it is around
540 ⁰C. The allowable difference is around ±5 to10 ⁰C
 Advantage of super-heated steam
1. Improve turbine efficiency
2. No harm can occurred to turbine blade due to wet steam
3. No rust will occur to turbine blade
4. Blades do not bend
 Steam temperature control in boiler
1. De-super heater
2. Gas recirculation fan
3. Fuel increased / decreased
4. Air flow control
5. Tilting of burner position
6. Soot blowing
7. Shot blasting
11.4.5 Re-heaters
Re-heater can also be termed as super heater. They can also be called as intermediate
super heaters. These are installed in flue gas duct. The get heat through flue gases and
rises wet steam temperature. There is no temperature different in re-heater or super
heater. However due no decrease in steam pressure it is called re-heater. The pressure
decreases due to line resistance.
 Duties of re-heaters
1. Re-heaters increase the temperature of cold reheat steam
2. They prevent the condensation of steam in I.P turbine.
3. Re-heater is a safety device of I.P turbine.
11.4.6 Boiler Water Tubes
 Down comers
Tubes that come downward from boiler are called down comers. These are located in
unheated zone. They contain feed water. Further due to less temperature of feed water
it become heavy comparison to steam, thus natural circulation of water occurs. The
feed water enters in boiler drum lower header. This is also called thermal circulation
of feed water.
 Up riser
Tubes that come from downward to boiler drum called up risers. In these tubes water
coverts into saturated steam that why they are called as generation tubes. These tubes

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are located inside the furnace and came into radiation zone, that’s why they get
maximum heat. These are also called water wall and also used as insulation of boiler.
11.4.7 Air pre-heater
Heating combustion air can raise boiler efficiency about 1% for every 40⁰F in
temperature increase. The most common way to preheat the air is with a heat
exchanger on the flue exhaust. Air pre-heater is installed into flue gases duct. The
heating element get heat from flue gases and passes it to the air going into furnace, so
that temperature of combustion air increased. This helps for proper fuel burning.
11.4.8 Forced Draught Fan
This fan intake air from turbine hall or boiler side and sent it through air pre heater in
the burners. This creates a positive draught in furnace.
11.4.9 Chimney / Stack
A vertical channel or pipe which conducts smoke and combustion gases up from a fire
or furnace and typically through the roof of a building.
Chimneys are made of steel or masonry or common bricks or perforated bricks.
Generally they are made of several sections. For short exhaust stack, steel chimneys
are preferred. Steel chimneys are usually preferred in the case of GTPS because a gas
turbine attains its full load in less than a minute and as such a chimney has to with
stand, a thermal shock resulting from the increase in temperature of 450~500 0C
during this period.

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11.4.10 Boiler Safety Valves
The boiler drums are manufactured on a specific pressure. Thus, in case the pressure
exceed beyond the capability of boiler drum can explode and due to explosion,
chaotic situation can occur in shape of fatal accident to human or machinery. Thus, to
prevent from this state boiler safety valves are installed which operates on specific
pressure. So whenever pressure exceed from limit these valve get operated
automatically.
11.5 TURBINE
Turbine is used to convert the heat energy into mechanical energy.
The load requirement is controlled by the steam flow through a governing valve.
Steam turbine has two parts.
1. HP turbine
2. LP turbine.
11.5.1 HP (High Pressure) Turbine
First of all steam from boiler comes into the HP turbine. Steam in the HP turbine is
called live steam or main steam. Rotor blades diameter of this part of turbine is
smallest of the other parts of the turbine. Inlet steam temperature of the HP turbine is
950 F and pressure is 1250 Psi.
11.5.2 LP (Low Pressure) Turbine
The outgoing steam of the IP turbine entered into the LP turbine. Steam from the LP
turbine goes into the condenser.

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11.5.3 Specification of the steam turbine
 Make Westinghouse USA
 Maximum load 66MW each unit
 Live steam pressure 1250 Psi
 Live steam temperature 950 F
 Rated speed 3000 rpm
 Super heater Outlet Temp 950+10 F
11.6 DC Supply:
As we all know that AC supply can’t be stored. Thus the back systems in power
houses are used built on DC supply system. It is a stand by source of electricity
available at every movement in shape of storage batteries in order to protect our main
system to damage.
11.6.1 Importance of DC supply
All the control and protection system is based on DC supply. Usually the AC supply
is converted to DC through rectifier. Further battery bank is also used which is charge
through rectifier. This DC produced by battery bank is used in emergency when AC is
not available. Moreover, during charging the chemical energy converts into electrical
energy.
11.6.2 Different parts of DC supply
 Rectifier
 Battery charger
 Battery cell 24VDC or 220VDC
11.7 Use of battery in power station
 Control of electrical equipment/ Field flashing
 Open / close of breakers
 Position indicators/ Control and protection system
 Emergency lights/ Emergency pumps

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CHAPTER 12- COOLING TOWER
Cooling tower
The cooling tower is used to cool the hot water. Which is used to cool the turbine,
generator and the boiler hot water.
Cooling Tower Fan Blades

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CHAPTER 13-
CENTRAL G.T MAINTENANCE WORKSHOP
13.1 Workshop’s History
This is the first and largest turbine maintenance workshop in Pakistan. The Workshop
is also involved in different maintenance/repair works for government and private
power plants. There are different kinds of machine using in the workshop for
repairing.
13.2 Maintenance workshops
 Cleaning shop
 NDT shop
 Welding shop
 Grainding shop
 Bering re-metalling shop
 Heat treatment shop
 Balancing shop
 Electrical shop
 Instrument/Electronics shop
 Chemical lab
13.3 Cleaning shop
The jobs which are the part of power plant accessories is treated cleaned first to
maintenance.
TYPES
 Vapor decreasing
 Vacuum blasting machine
 Vapor blasting machine
 Steam jet cleaner
 Open dry blasting machine
 Sand blasting machine

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13.4 NDT shop
The NDT stands for non- destructive test. In the shop we analysis and search
the crack in the job’s part. There are some methods used for the testing that can show
that place of the crack. The methods are describe below
 Xyglo test check
 Visual inspection
 Penetrate test
 Magnetic particle inspection
 Ultrasonic test
Xyglo test set
This test is used to scan the job and mark the cracks in the internal and external sides
of the job body. This test is completed in following steps.
Chamber 01: Self emulsifying
Chamber 02: washing
Chamber 03: drying
Chamber 04: Developing powder
13.5 Welding shop
Welding types
 Gas welding
 Tig (argon) welding
 Arc welding

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Gas welding
In this type of welding Oxyacetylene gases are used for welding.
Flame types
i. Natural flame [oxy (low) DS (low)]
ii. Carburizing flame [oxy (low) DS (high)]
iii. Oxidizing flame [oxy (high) DS (low)]
Flame parts
i. Inner core
ii. Envelop
Arc welding
Shielded Metal Arc welding is the process of joining two metal pieces using a flux
covered electrode which is melted in an electric arc.
Welding position
i. Flat G1 position
ii. Horizontal G2 position
iii. Vertical G3 position
iv. Over head G4 position
v. 180 degree G5 position
vi. 45 degree G6 position

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13.6 Grainding shop
Types
i. Strate grainding
ii. Angle pneumatic grainding
iii. Electric grainding
Cutter types
i. Stone cutter
ii. T-shape cutter
iii. Tree shape cutter
iv. Cylinder cutter
v. Ball cutter
vi. Flap wheel cutter
vii. Disk type

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13.7 Bering re-metalling shop
In General bearing the pads are made of white metal (nickel chromium + lead) first of
all the cracked metal melted using furnace after the removal of white metal to weld
the white metal on bearing pads surface should be neat and clean.

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13.8 Heat treatment shop
Heat treatment shop is used to heat the job/bearing to hardening the metals. In heat
treatment furnace resistive heating elements are used to heat the job.
13.9 Balancing shop
After the machine welding , grinding and machining turbine rotor should be balance
for that rotor bring to the balancing shop rotor is placed on the top of machine pads
prime mover moves the rotor balancing speed 200-250 rpm un balanced rotor spots
are shown on the computer screen then we weld a small wait on that sport

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13.10 Electrical Shop
Motor, generator are wounded In workshop, electrical faults of all machines in
workshop and all CT,PT’s switch gears, lights, motor starters & switch boards are
repaired.
13.11 Machine shop
Vertical lathe machine SC33
Chuck Diameter = 3300mm
Max Transverse = 2300mm
Max weight = 3500kg
Made in ROMANIA
Heavy Duty Machine (Rotor Balancing Machine)
Rotor weight = 2500-6000 kg
Max length of rotor= 8000 mm
Max Dia of rotor = 4000 mm
Rotor journal dia = 40-900 mm
Made in SCHENCK, GERMANY

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CNC lathe machine
Chuck Dia = 4000mm
Swing on BED = 4200mm
Length center to center= 15000mm
Job holding capacity = 100tons
Made in CHINA

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Skill attained
 Complete start up of gas turbine processing.
 Operation and maintenance work on 11kv switch gears V.C.B vacuum circuit
breakers.
 Work on (A.C.B) air circuit breakers, (SF6) gas circuit breakers.
 Maintenance & operation work on (M.C.R) master control room.
 Maintenance work on motor starters (DOL) star delta & frequency control
invertors.
 Over hailing & maintenance of three phase induction motors.
 Maintenance of air conditioners.
 Work on D.C motors and batteries.
 Work on measuring instruments & transformers P.T & C.T.
 Work in Cleaning shop, N.D testing shop, Welding shop and grinding shop.
 Check all system and remove problems during running system.

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Recommendations
I found a very good practical learning environment at GENCO III (NPGCL). Some
recommendations are given for the students who want to do their internship program.
Undergraduate Internship Report Department of Electrical Engineering, Govt.
College University
 Students must complete the courses related to their internship before
beginning the program. Completing the related courses before the internship
helps the students to understand the topic better.
 During training period there may be any fault in the general activities of
power plant. It is necessary to learn about fault and how the engineers repair
the faulty part. Students should visit that faulty section and should try to get a
brief lecture on that fault from their mentor.

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Abbreviations
01 WAPDA Water and power development authority
02 AC Alternating current
03 CGTMW Central gas turbine maintenance workshop
04 CWP Circulating water pump
05 CT Current transformer
06 CNC Computer numeric calculation
07 DC Direct current
08 FD Force draft
09 FWP Feed water pump
10 GTPS Gas turbine power station
11 GENCO Generation company
12 HSD High speed diesel
13 HP HEATER High pressure heater
14 HP TURBINE High pressure turbine
15 HZ Hertz
16 HTV High tension voltage
17 LP TURBINE Low pressure turbine
18 LP HETAR Low pressure heater
19 LTV Low tension voltage
20 Lb. Pounds
21 NPGCL North power generation limited
22 NDT Non distractive test
23 OCB Oil circuit backer
24 PT Potential transformer
25 P.F Power factor
26 Psi Pressure stander international
27 RTD Resistance temperature detector
28 RPM Revolution per minute
29 SPS Steam power station
30 SF6 Sulfur hexa florid
31 SWG Stander wire gauge
32 TIG Tungsten inert gas
33 Tem. Temperature
34 VCB Vacuum circuit breaker
35 AVR Auto voltage regulator

Industrial training report (GENCO-iii) by ( Engr. GHIAS-UD-DIN)

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