barh super thermal power plant report
TRANSCRIPT
1
Barh Super Thermal Power Plant
A
PRACTRICAL TRAINING REPORT
Submitted for the Partial Fulfilment of the Requirement of the
Degree
BACHELOR OF TECHNOLOGY
In
ELECTRICAL ENGINEERING
Submitted to: Submitted By:
Prof Kusum Agrawal Jay Pratap
(Head-EE) (IV B. Tech., VII Sem.)
Department of Electrical Engineering
Jodhpur Institute of Engineering & Technology,
JIET Group of Institutions, Jodhpur.
Rajasthan Technical University, Kota (Raj.)
2016-17
2
CONTENT
Chapter Page No.
1. National Thermal Power Plant 1-8
1.1 Introduction 1
1.2 Journey of NTPC 2
1.3 Installed Capacity 3
1.3.1 Coal Based Power Stations 4
1.3.1.1 Coal Based Joint Ventures/Subsidiaries 5
1.3.2 Gas Based Power Station 5
1.3.3 Hydro Based Power Projects 6
1.3.4 Renewable Energy 7
1.3.4.1 Solar Energy 7
1.3.4.2 Hydro Energy 7
1.3.4.3 Geothermal Energy 8
2. Barh Super Thermal Power Plant 9-11
2.1 Introduction 9
2.2 Site Selection Criteria 9
2.3 Project Cost 10
2.4 Beneficiary State 10
2.5 Design Features 11
3. Coal Handling Plant 12-15
3.1 Introduction 12
3.2 Wagon Unloading System 13
3.2.1 Wagon Tripler 13
3.2.2 Crushing System 13
3.2.3 Crusher House\ 13
3.3 Construction & Operation 14
3.4 Conveying System 14
4. Ash Handling Plant 16-17
4.1 Introduction 16
4.2 Fuel and ash plant 16
4.3 Air & Gas Plant 16
4.4 Ash Disposal & Dust Collection Plant 17
4.5 Utilisation 17
3
5. Water Treatment Plant 18-20
3.1 Introduction 18
3.2 Process of Purification 18
3.3 De mineralizing Plant 19
6. Pulveriser Plant 21-23
6.1 Introduction 21 6.2 Fundamental Requirement of a Pulveriser 21
6.3 Raw Coal Feeders 21 4.3.1 Rotary Volumetric Feeder 21
6.4 Pulverisers 22
6.5 Bowl Mill 22
6.6 Factors Affecting Mill Performance 23
7. Boiler 24-25
7.1 Introduction 24
7.2 Function of boiler drum 24
7.3 Steam Separator 24
7.4 Super Heater 24
7.5 Re-Heater 25
7.6 Economizer 25
7.6.1 Economiser Failure 25
7.7 Furnace 25
8. Turbine 26-27
8.1 Introduction 26
8.2 Working Principle of the Steam Turbine 26
8.3 Turbine Type 26
8.3.1 Impulse Turbine 26
8.3.2 Reaction Turbine 27
8.4 Classification of the Steam Turbine 27
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9. Generator 28-33
9.1 Introduction 28
9.2 Parts of Generator 28
9.3 Starting of Generator 30
9.4 Shutting Down of Generator 31
9.5 Excitation System 31
9.6 Types of Excitation 32
9.7 Turbo Generator Specification 32
10. Switchyard 34-38
10.1 Introduction 34
10.1.1 400KV Switchyard 34
10.1.2 132KV Switchyard 34
10.2 Components of Switchyard 35
11. Transformer 39-44
11.1 Introduction 39
11.2 Classification 41
11.3 Generating Transformer 41
11.4 Inter Connecting Transformer 42
11.5 Station transformer 43
11.6 Unit Transformer 43
11.7 Miscellaneous Service transformer 44
CONCLUSION 45
REFERENCES 46
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TABLE LIST
Table No Table Name Page No
1.1 Installed Capacity Overview 3
1.2 Regional Spread of Generating Facilities 3
1.3 Coal Based power stations 4
1.4 Coal Based Joint Ventures/Subsidiaries 5
1.5 Gas /Liq. Fuel Based Power Station 5
1.6 Power Plants with Joint Ventures 6
1.7 Hydro Based Power Plan 7
1.8 Projects Commissioned (360 MW) 8
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FIGURE LIST
Figure No Figure Name Page No
1.1 Inside a Hydropower Plant 6
1.2 Geothermal Power Plant 8
2.1 Barh Super Thermal Power Plant 9
3.1 Processing of Coal Handling Plant 12
3.2 Coal Crushing System 13
5.1 Flow dig of Process of Purification 18
8.1 Multi Stage steam Turbine Generator 26
9.1 Cross Section View Generator 30
10.1 Component of Switchyard 35
10.2 Connection of current transformer 36
11.1 Cross Section View Transformer 39
11.2 Generator transformer 42
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CHAPTER 1
NATIONAL THERMAL POWER PLANT
1.1 Introduction
NTPC, the largest power company in India was setup in 1975 to accelerate power
development in the country. It is world’s largest and most efficient power generation
companies. In Forbes list of 2000 Largest Companies for the year 2007, NTPC occupies
411th place.
NTPC has installed capacities of 47,228MW. It has 18 coal based power station (35,085
MW), 7 gas based power station (4,017 MW), and 9 power station in joint Ventures (6,966
MW). 1 hydro based power station (800 MW). And 9 Renewable energy projects (360
MW). The company has power generating facilities in all major regions of the country. It
plans to be a 75,000MW company by 2017
NTPC has gone beyond the thermal power generation. It has diversified into hydro
power, coal mining , power equipment manufacturing ,oil and gas exploration, power
trading & distridution. NTPC is now in the entire power value chain and is poised to
become an integrated power Major. NTPC share on 31mar 2008 in the total installed
4000
6000
100001100011000
1200013000
1400015000
170001750018000
225002250023500
2200021000
2400023000
28000
Series 1, 30000
0
5000
10000
15000
20000
25000
30000
35000
M W
Growth of NTPC Installed Capacity
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capacity of the country was 19.1% and it contributed 28.50% of total power generation of
the country during 2007-08. NTPC has set new benchmarks for power industry both in the
area of power construction and operation.
With its experience and expertise in the power section. NTPC is extending consultancy
services to various organisations in the power business. It provide consultancy in the area
of power plant construction and power generation companies in India and abroad. IN
November 2004, NTPC came out with its initial public offering (IPO) consisting of 5.25%
as fresh issue and 5.25% as offer for sale by government of India. NTPC thus became a
listed company with government holding 89.5% of the equity share capital and rest held by
institutional investors and public. The issue was a resounding success. NTPC is among the
largest five companies in India in term of market capitalization.
Recognising its excellent performance and vast potential, government of the India has
identified NTPC as one of the jewels of public sector ‘Navratnas’-a potential global glant.
Inspired by its glorious past and vibrant present, NTPC is well on its way to realise its
vision of being “A world class integrated power major, powering India’s growth, with
increasing global presence”.
1.2 Journey of NTPC
1975:-NTPC was set up in 1975 with 100% ownership by the government of India.
In the last 30 year, NTPC has grown into the largest power utility in India
1997:- in 1997, government of India granted NTPC status of ‘Navratna’ being one
of the nine jewels of India.
2004:-NTPC become a listed company with majority government ownership of
89.5%, NTPC become 3rd largest by market capitalisation of listed companies
2005:-the company rechristened as NTPC limited in the line with its changing
business portfolio and transform itself from a thermal power utility to an integrated
power utility.
2008:-national thermal power corporation is largest power Generation Company in
India. Forbes global 2000 for 2008 ranked it 411th in the world.
2009:- national thermal power corporation is largest power Generation Company in
India. Forbes global 2000 for 2008 ranked it 317th in the world.
2012:-NTPC has also set up a plan to achieve a target of 50,000MW generation
capacity.
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2017:-NTPC has embarked on plans to become a 75,000MW company by 2017
1.3 Installed Capacity
Present installed capacity of NTPC is 47,228 MW (including 6,966 MW through
JVs/Subsidiaries) comprising of 44 NTPC Stations (18 Coal based stations, 7 combined
cycle gas/liquid fuel based stations, 1 Hydro based station), 9 Joint Venture stations (8 coal
based and one gas based) and 9 renewable energy projects
Table-1.1 Installed Capacity Overview
No of Plants Capacity MW
NTPC Owned
Coal 18 35,085
Gas /Liquid full 7 4,017
Hydro 1 800
Renewable energy
projects (Solar PV)
9 360
TOTAL 35 40,012
Owned By jvs
Coal & Gas 9 6,966
TOTAL 44 47,228
Table-1.2 Regional Spread of Generating Facilities
Region Coal Gas/liquid fuel Renewable Total
Northern 9,015 2,344 35 11,394
Western 12,000 1,313 50 13,363
Southern 4,600 360 260 5,220
Eastern 9,470 - 10 9,480
Island - - 5 5
Hydro - - - 800
JVs 4,999 1,967 - 6,966
Total 40,084 5,984 360 47,228
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1.3.1 Coal Based Power Stations
With 18 coal based power stations, NTPC is the largest thermal power generating company
in the country. The company has a coal based installed capacity of 35,085 MW.
Table-1.3 Coal Based power stations
Sr.
No.
Coal based (Owned by
NTPC)
State Commissioned
Capacity
(MW)
1 Singrauli Uttar Pradesh 2,000
2 Korba Chhattisgarh 2,600
3 Ramagundam Telangana 2,600
4 Farakka West Bengal 2,100
5 Vindhyachal Madhya Pradesh 4,760
6 Rihand Uttar Pradesh 3,000
7 Kahalgaon Bihar 2,340
8 Dadri Uttar Pradesh 1,820
9 Talcher kanitha Orissa 3,000
10 Feroze Gandhi Unchahar Uttar Pradesh 1,050
11 Talcher Thermal Orissa 460
12 Simhadri Andhra Pradesh 2,000
13 Tanda Utter Pradesh 440
14 Badarpur Delhi 705
15 Sipat Chhattisgarh 2,980
16 Mauda Maharashta 1,660
17 Barh Bihar 1,320
18 Bongaigaon Assam 250
Total (Coal) 35,085
1.3.1.1 Coal Based Joint Ventures/Subsidiaries
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Table-1.4 Coal Based Joint Ventures/Subsidiaries
Sr. No. Coal Based (Owned by
JVs/Subsidiaries)
State Commissioned (MW)
1 Durgapur West Bengal 120
2 Rourkela Orissa 120
3 Bhilai Chhattisgarh 574
4 Kanti Bihar 610
5 IGSTPP, Jhajjar Harayana 1500
6 Vallur Tamil Nadu 1500
7 Nabinagar-BRBCL Bihar 250
8 PUVNL(Patratu) Jharkhand 325
Total 4,999
1.3.2 Gas Based Power Stations
The details of NTPC gas based power stations is as follows
Table-1.5 Gas /Liq. Fuel Based Power Station
Sr. No. Gas based
(Owned by NTPC)
State Commissioned
Capacity (MW)
1 Anta Rajasthan 419.33
2 Auraiya Uttar Pradesh 663.33
3 Kawas Gujarat 656.20
4 Dadri Uttar Pradesh 829.78
5 Jhanor-Gandhar Gujarat 657.39
6 Rajiv Gandhi CCPP
Kayamkulam
Kerala 359.58
7 Faridabad Haryana 431.59
Total 4,017.23
Table-1.6 Power Plants with Joint Ventures
12
Sr.
No.
Coal based
(Owned by
NTPC)
State Commissioned
Capacity (MW)
1 RCPPL Maharashtra 1967.08
TOTAL 1,967.08
1.3.3 Hydro Based Power Projects
Fig:-1.1 Inside a Hydropower Plant
NTPC has increased thrust on hydro development for a balanced portfolio for long term
sustainability. The first step in this direction was taken by initiating investment in Koldam
Hydro Electric Power Project located on Satluj River in Bilaspur district of Himachal
Pradesh. Other hydro project under construction is Tapovan Vishnugad. On all these
projects construction activities are in full swing.
Table -1.7 Hydro Based Power Plant
SR.
No.
Hydro Based State Approved
Capacity
Commission
Capacity (MW)
1 Koldam(HEPP) Himachal
Pradesh
800 800
2 Tapovan
Vishnugad (HEPP)
Uttrakhand 520 -
3 Singrauli CW
Discharge(Small
Hydro)
Uttar Pradesh 8 -
13
4 Lata Tapovan Uttrakhand 171 -
5 Rammam West Bengal 120 -
Total 1,519 800
1.3.4 Renewable Energy
The future lies with renewable energy. Renewable energy technologies provide clean and
green sources of electricity. With their abundance supply, they form the backbone for
India’s energy security and ‘energy independence’ as envisaged by 2020. We aim to
transform NTPC into the country's largest green power producer in the coming years. Green
power is national power.
1.3.4.1 Solar Energy:
Table 1.8 -Projects Commissioned (360 MW)
Sr. No. Project State Capacity (MW)
1 Dadri Solar PV Uttar Pradesh 5
2 Port blair Solar PV Andaman & Nicobar
Island
5
3 Ramagundam Solar PV
(Phase -I)
Telangana 10
4 Talcher Kaniha Solar PV Odisha 10
5 Faridabad Solar PV Harayana 5
6 Unchahar Solar PV Uttar Pradesh 10
7 Rajgarh Solar PV Bihar 50
8 Singrauli Solar PV Uttar Pradesh 15
9 Ananthapuram Solar PV Andhra Pradesh 250
Total 360
1.3.4.2 Hydro Energy:
Projects under Execution (8 MW)
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8 MW hydro energy based project at NTPC-Singrauli in Uttar Pradesh.
1.3.4.3 Geothermal Energy:
Fig1.2:-Geothermal Power Plant
Tattapani Geothermal Project in Chhattisgarh: MoU Signed with Govt. of Chhattisgarh.
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CHAPTER 2
BARH SUPER THERMAL POWER PLANT
2.1 Introduction
Barh Super Thermal Power Plant (BSTPP) or NTPC Barh is located in Barh ( Bihar) .NTPC
Barh is located nearly four kilometres east of the Barh subdivision on National Highway31
in Patna district. The project has been named a mega power project, and is owned by Indian
energy company National Thermal Power Corporation.
Fig:-2.1 Barh Super Thermal Power Plant
The Barh super thermal power plants consist of two stages and total generation unit is five.
In the 1st stage 1,980MW (3x660MW) built by Russian firm Technopromexport (TPE) and
2nd stage 1,320MW (2x660MW) extension is being built by BHEL.
The main power plant and the township is spread over an area of 1,186 acres. The legal
possession of 1,186 acres of land has been acquired for setting up the main
Power plant and its township which includes 12 villages.
The PM, Atal Bihari Vajpayee, had laid the foundation stone of the main plant of stage1
of NTPC
Barh on March 6, 1999. The formal inauguration of its site office and laying of the
foundation stone of the training centre at the plant site was done in September
2003. Former Union power minister Sushil Kumar Shinde had inaugurated the main plant
house of stage2 of NTPC Barh on May 29, 2006.
2.2 Site Selection Criteria
1 Background
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Barh super thermal power plant, stage 1and stage 2 is set by NTPC is located in Barh in
Patna district of Bihar state. The total generating unit is 660MW each. In stage 1there are
3 unites and in stage 2 there are 2 unites. The total capacity of the project will be 3300 MW
(3X660 MW+2X660 MW).
2 Location
The project site is located about 3kms east of Barh town in Patna district in the state of
Bihar, having a latitude and longitude of 25 deg 28' N and 85deg 45' E respectively. The
plant and township are located between NH-31 and railway line. The ash disposal area is
located in the south of the railway line
3 Land Requirement
Approximately 1200 acres of land has been identified between NH-1 and railway lines for
the plant area, switchyard, green belt, labour colony, ash based units and township.
Approximately 1750 acres of land has been identified for the ash disposal area in the south
of railway line
4 Water Requirement
The project site is located near the river Ganga. The makeup water requirement for the
project is proposed to be drawn from river Ganga.
5 Coal requirement
Hazaribagh coal mines. Coal requirement for the project in estimated as 10 million
tones/annum considering a GCV of 3350 kcal/kg and 80% PLF.
2.3 Project Cost
The total production of the plant is 3,300MW at the cost of Rs 26,000 crores. In the 1st stage
(3x660MW) total approved cost is Rs 8,692.97 crores. And the 2nd stage (2x660MW) total
approved cost is Rs 7,688.12 crores
2.4 Beneficiary state
The states & UTs of Northern & Western regions and state of Bihar
2.5 Design Features
The satisfactory design consists of the flowing steps.
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1. Estimation of cost.
2. Selection of site.
3. Capacity of Power Station.
4. Selection of Boiler & Turbine.
5. Selection of Condensing Unit.
6. Selection of Electrical Generator.
7. Selection of Cooling System.
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CHAPTER 3
COAL HANDLING PLANT
3.1 Introduction
In the thermal power plant required large amount coal so it required to store. In the thermal
power plant the coal is store in the coal handling plant. The main purpose of coal handing
plant to store in huge amount of coal for continuous generation of power in thermal power
plant.
The coal is brought to the NTPC, Barh through rails. The main coal sources for NTPC,
Barh are hazaribagh coal mine. The Coal transported to the project site through Indian
railways system for a distance of approximately 250kms via shorter route Coal requirement
for the project in estimated as 10 million tones/annum considering a GCV of 3350kcal/kg
and 80% PLF. The coal is firstly unloaded from wagon by wagon triplers then crushed by
crushers and magnetic pulley and pulverized to be transformed to the boiler. The whole
transportation of coal is through conveyor belt operated by 3-Ø Induction motor.
Fig 3.1:-Processing of Coal Handling Plant
The coal handling plant can broadly be divided into three sections:-
1) Wagon Unloading System.
2) Crushing System.
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3) Conveying System.
3.2 Wagon Unloading System
3.2.1 Wagon Tripler
Unloads the coal from wagon to hopper to hopper with the help of wagon Tripler. The
Hopper, which is made of Iron, is in the form of net so that coal pieces of only equal to and
less than 200 mm. size pass through it. The bigger ones are broken by the workers with the
help of hammers. From the hopper coal pieces fall on the vibrator. It is a mechanical system
having two rollers each at its ends.
The four rollers place themselves respectively behind the first and the last pair of wheels
of the wagon. When the motor operates the rollers roll in forward direction moving the
wagon towards the “Wagon Table”. On the Wagon table a limit is specified in which
wagon to be has kept otherwise the triple would not be achieved.
3.2.2 Crushing System
Fig 3.2:- Coal Crushing System
3.2.3 Crusher House
It consists of crushers which are used to crush the coal to 20 mm. size. There are mainly
two type of crushers working in STPP, Barh:-
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1. Primary Crushers i.e. i) Rail crushers or ii) Rotary breaker.
2. Secondary Crushers. I.e. Ring granulators.
1 Primary Crushers
Primary crushers are provided in only CHP stage 3 system, which breaking of coal in CHO
Stage 1 & Stage 2 system is done at wagon tripler hopper jail up to the size (-) 250 mm.
2 Secondary Crusher
Basically there are four ways to reduce material size: impact attrition, Shearing and
Compression. Most of the crushers employ a combination of three crushing methods. Ring
granulators crush by compressing accompanied by impact and shearing. The unique feature
of this granulator is the minimum power required for tone for this type of material to be
crushed compared to that of other type of crushers.
3.3 Construction & Operation
Secondary crushers are ring type granulators crushing at the rate of 550 TPH / 750 TPH for
input size of 250 mm. and output size of 20 mm. The crusher is coupled with motor and
gearbox by fluid coupling.
Main parts of granulator like break plates, cages, crushing rings and other internal parts are
made of tough manganese (Mn) steel.
The rotor consists of four rows of crushing rings each set having 20 Nos. of toothed rings
and 18 Nos. of plain rings. In CHP Stage 1 & 2 having 64 Nos. of ring hammers. These
rows are hung on a pair of suspension shaft mounted on rotor discs.Crushers of this type
employ the centrifugal force of swinging rings stroking the coal to produce the crushing
action. The coal is admitted at the top and the rings stroke the coal downward. The coal
discharges through grating at the bottom.
3.4 Conveying System
Belt are used to convey coal from coal handling plant to furnace
3.4.1 Specification
Belt 1400mm
21
Speed 2.2m/s
Total Install Power 360kw
Capacity 1350/750 ton/hr.
No of Conveyor 38
22
CHAPTER 4
ASH HANDLING PLANT
4.1 introduction
A natural result from the burning of fossil fuels, particularly coal, is the emission of flyash.
Ash is mineral matter present in the fuel. For a pulverized coal unit, 60-80% of ash leaves
with the flue gas
This plant can be divided into 3 sub plants as follows:-
1) Fuel and Ash Plant.
2) Air and Gas Plant.
3) Ash Disposal and & Dust Collection Plant.
4.2 Fuel and ash plant
Coal is used as combustion material in STPP, Barh. In order to get an efficient utilization
of coal mills. The Pulverization also increases the overall efficiency and flexibility of
boilers. However for light up and with stand static load, oil burners are also used. Ash
produced as the result of combustion of coal is connected and removed by ash handling
plant. Ash Handling Plant at STPP, Barh consists of specially designed bottom ash and fly
ash in electro static precipitator economizer and air pre-heaters hoppers.
4.3 Air & Gas Plant
Air from atmosphere is supplied to combustion chamber of boiler through the action of
forced draft fan. In STPP, Barh there are two FD fans and three ID fans available for draft
system per unit. The air before being supplied to the boiler passes through preheater where
the flue gases heat it. The pre heating of primary air causes improved and intensified
combustion of coal.
The flue gases formed due to combustion of coal first passes round the boiler tubes and
then it passes through the super heater and then through economizer. In re-heater the
temperature of the steam (CRH) coming from the HP turbines heated with increasing the
number of steps of re-heater the efficiency of cycle also increases. In economizer the heat
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of flue gases raises the temperature of feed water. Finally the flue gases after passing
through the Electro-Static Precipitator is exhausted through chimney.
4.4 Ash Disposal & Dust Collection Plant
STPP, Barh has dry bottom furnace. Ash Handling Plant consists of especially designed
bottom and fly ash system for two path boiler. The system for both units is identical and
following description is applied to both the units the water compounded bottom ash hopper
receives the bottom ash from the furnace from where it is stores and discharged through
the clinker grinder. Two slurry pumps are provided which is common to both units & used
to make slurry and further transportation to ash dyke through pipe line.
Dry free fly ash is collected in two number of 31 fly ash hoppers which are handled by two
independent fly ash system. The ash is removed from fly ash hoppers in dry state is carried
to the collecting equipment where it is mixed with water and resulting slurry sump is
discharged
4.5 Utilisation
Utilisation of coal-ash is always practise than its disposal. There are various methods of
utilisation of coal-ash along with established engineering technologies some of them are
mentioned below:
Manufacturing of building materials.
Making of concrete.
Manufacturing of pozzuolana cement.
Road construction etc.
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CHAPTER 5
WATER TREATMENT PLANT
5.1 Introduction
All natural sources of water contain impurities as well as dissolved gasses. The amount of
these impurities depends on type of water source and location.
The main impurities are:-
1. Suspended (Macro Size)-sand, dirt, silt, this contributes turbidity to raw water
2. Colloidal-micro size particles (1-100mm)
3. Dissolved form –Alkaline salt and neutral salts organic matter,
Alkaline salts are mainly bicarbonates rarely carbonates and hydrate of calcium,
magnesium and sodium
Neutral salts are sulphate, chloride, nitrates of calcium, magnesium and sodium
5.2 Process of purification
Fig 5.1:-Flow dig of Process of Purification
1. The raw water is taken from cooling water plant & reservoir.
2. The chemicals are added such as (ALUM+LIME/PAC & CL2) and remove impurities
in the water
3. This water is fed to flash mixer, which consist of a 900 rotated path for purpose of
mixing chemicals, which are added to water. In BSTPP natural mixing is used.
25
4. Then this water is fed to cloriflocculatar tank which consist of cylindrical shape and
two stage water is fed in internal stage & from bottom it comes to outer stage &all
impurities form flock and settle down in inner portion so it is said flocculated zone. The
pure water comes to outer portion in which cl2 is dissolved so it is said clarifier zone.
The water from clariflacculatar tank is fed to filter bed in BSTPP gravity bed are used
to remove impurities.
5. Then the water is fed to sump which is a big tank with no portion open. It is to store
pure water.
6. With help of pumps the water is fed to place of utilization. Various pumps are
A. Potable water pump: for supplying drinking water.
B. Back wash water pump: for reversing cycle of water for washing filter bed.
C. Filtered water pump: to supply water to make steam.
D. Filter water treatment pump: To fed water to D.M plant
5.3 De mineralizing plant
Water mainly in plant is used for cooling purpose. In this process water must be free from
all dissolved impurities.
This plant consist of two stream each stream with activated carbon filter , weak acid ,carbon
exchanger and mixed bed exchanger .The filter water to DM water plant through 250 dia
header from where a header top off has been taken off to softening plant. Two filtered water
booster pumps are provided on filtered water line for meeting the pressure requirement in
D.M plant.
Sodium sulphate solution of required is dosed into different filtered water by mean of
dosing pump to neutralize cl 2 prior to activated carbon filter. When water passes on
activated carbon filter will remove the residual chlorine from water provision is made for
back washing the activated carbon filter enter works acid carbon unit the deletion water
enter the weak base anion exchanger unit water then enter degasified unit where free co 2
is scrubbed out of water by upward counter flow of low pressure air flow through degasified
lower and degassed water is pumped to strong base exchanger.
CATION EXCHANGER.
R-H + Ca+2 R2-Ca + H+
26
ANION EXCHANGER
R-OH + Cl- R-Cl + OH-
H+ + OH - H20
Arrangement for designing ammonia solution into de-mineralized water after mixed bed
unit has been provided for ph correction before water is taken into be condensate transfer
pump the DM water to unit condenser as make up the softening plant is a designed to
produce 100 cubic m/Hr. of softened water per stream.
27
CHAPTER 6
PULVERISER PLANT
6.1 Introduction
Of the three commercial fuels- coal, petroleum, natural gas, and coal is the basic fuel used
in the boiler for the power generation due to its distribution and availability. Though coal
can be burnt in a boiler in many ways such a hand firing, stoking firing, pulverised coal
firing, cyclone furnace etc, and pulverised coal firing is favoured over other methods of
burning coal because of many advantages. About 80% of the coals for the generation of
electricity are burnt in the pulverised form.
6.2 Fundamental Requirement Of A Pulverised Plant
Supply of coal in the pulverised form to the boiler furnace can be accomplished by using
different type of equipment and systems. The use of a particular type of equipment is
decided on the type of coal used, boiler requirements, user preference etc.
1. Raw coal feeding
2. Drying
3. Grinding and circulating
4. Classifying
5. Transporting
6.3 Raw Coal Feeders
A raw coal feeder is a device that supplies the pulveriser with an uninterrupted flow of raw
coal from the bunker to meet system requirements. The feeders have to regulate the rate
of the coal flow corresponding to boiler load, calorific value of coal etc.
6.3.1 R o t a r y V o l u m e t r i c F e e d e r
In this type of feeder, a spider wheel is keyed to the centre of a feed roll shaft. This
shaft extends through a cylindrical core, which form the base of the feed roll. The core
is made in two halves, which are bolted to the opposite side of the feeder body, and the
spider wheel is placed in between these two halves. Numbers of plates are bolted to the
spider wheel along its periphery; these are making number of pockets. When the feeder
runs, the coal is received by the pockets formed by the plates and emptied into the
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pulveriser at a rate, which depends on the speed of the feeder. A hinged levelling gate
held in place by spring pressure limits the amount of coal entering each pocket but allows
passage of foreign material, which might otherwise cause damage to the feeder.
6.4 Pulverisers
To effect the coal particle size reduction, needed for pulverised coal firing, machine known
as pulverisers or mill are used to grind or comminute the coal. The pulverisers are generally
based on rock and mineral-ore grinding machinery. Five major type of coal mills used
are tabulated below according to their speed
Mill Speed
Bowl mill 50-100rpm
Ball mill below 50rpm
Impact or hammer mill above 225rpm
Bearer wheel mill above 225rpm
Drum mill/ tube mill below 50rpm
6.5 Bowl Mill
Bowl mill is a vertical spindle medium speed mill. In a bowl mill the coal is pulverised
between a disc called bowl rotated by the drive assembly and rollers kept above the disc
loaded by spring loading device.
Raymond mill mostly use in Indian Thermal Power Station. Vertically this mill is divided
into four major sections;
1 Mill base or gear box
2 Mill side assembly
3. Separator body
4. Separator body top.
Coal from the raw coal feeder is fed at the centre of the bowl through a raw coal inlet chute
inserted at the centre of the separator body top. Due to centrifugal force the coal moves
towards the periphery. The three rolls exert the required grinding pressure through the
springs. The primary air supplied to the mill side moves up through the vanes around the
bowl. By the deflector liners air is deflected towards the centre of the mill which causes
29
recirculation of coal throughout the grinding area. The airs moving upwards picks fine coal
and inter the classifier through the vanes. The vanes introduces spin and as a result course
particles get separated from the stream and return through the annulus between the centre
of the feed pipe and classifier cone to the bowl for further grinding. Fine coal moves out
with air through the multiport assembly at the outlet of the classifier.
6.6 Factors Affecting Mill Performance
The performance of the mill plant especially the pulveriser output is affected by number
of factor mainly associated with the properties of coal being ground. Important of these
factors are
• Grind ability index of coal
• Fineness of milled product
• Moisture content
• Size of the row coal
• Mill wear
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CHPTER 7
BOILER
7.1 Introduction
A boiler, also called steam generator, is designed so that heat transfer takes place between
boiler tube bundles (also called U bundles) and boiler water in the boiling area. If the U
bundles are not completely submerged, the heat transfer area, hence heat transfer rate,
hence heat sink capability decreases.
7.2 Function of Boiler Drum
The functions of the boiler drum are.
A) Separation of the saturated steam from the steam-water mixture produced by
evaporating tubes.
B) Mixing feed water from economiser and water separated from steam –water
mixture, and recirculation through the tubes.
C) Carrying out blow down for reduction of the boiler water salt concentration.
D) Treatment of the boiler water by chemical.
7.3 Steam Separator
In recirculation type of the boiler the evaporating tube supply only a steam-water mixture
to the drum. From this, the steam of high purity acceptable to the super heater and turbine
is to be separated. This separation is to be done in the limited space in the drum. Numbers
of the factors influence the separation of the water from the steam in drum; important
among them are:
The density of the water with respect to the steam.
The amount of the water in the mixture delivered to drum.
Viscosity, surface tension and other factor affected by pressure
Water level in the drum
The concentration of boiler water solids
The available pressure drop from drum internal design
In this power plant TURBO SEPARATORS are use (95 separators).
7.4 Super Heater
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Super heating of the steam is done in 14 stages. These stages having following purpose,
Heating of the steam in stage or increase of the temperature in number of the
stage.
In these stages, we also use spray for cooling the steam.
7.5 Re-Heater
Re-heater is use to re-heat the steam for the use of intermediate pressure turbine (at the
same pressure of the outlet of the HP turbine). In the re-heater steam comes from HP
turbine through CRH L&R (cold re-heat) and after re-heater steam goes to intermediate
turbine through HRH L&R (hot re- heat).
7.6 Economiser
Economisers are provided in the boilers to improve the efficiency of the boiler by
extracting the heat from the flue gases and add it as either sensible heat alone or
sensible heat and latent heat to the feed water before the water enter the evaporating surface
of the boiler.
Advantage
Provision of the economiser in the boiler brings two major advantages.
1. As the economiser recovers the heat in flue gas that leaves the boiler.
2. As the feed water is preheated in the economiser.
7.6.1 Economiser Failure
1 Over heating
2 Corrosion
3 Erosion
7.7 Furnace
Furnace is primary part of the boiler where the chemical energy available in the fuel is
converted into thermal energy by combustion. Furnace is designed for efficient and
complete combustion. Major factors that assist for efficient combustion are the temperature
inside the furnace and turbulence, which causes rapid mixing of fuel and air
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CHPTER 8
TURBINE
8.1 Introduction
Steam turbine is a rotating machine which converts heat energy of the steam to mechanical
energy.
8.2 Working Principal Of The Steam Turbine
Fig 8.1:-Multi Stage steam Turbine Generator
When the steam is allowed to expand through a narrow orifice, its assumes kinetic
energy at the expense of its enthalpy. This kinetic energy changes to mechanical energy
through the impact (impulse) or reaction of the steam against the blades.
It should be realized that the blade of the turbine obtains no motion force from the static
pressure of the steam or from any impact of the steam jet. The blades are designed
in such way, that steam will guide on or off the blade without any tendency to
strike it.
8.3 Turbine Type
Basically there are two broad classifications of the steam turbines,
1. Impules Turbine
2. Recation Turbine
8.3.1 Impulse Turbine
In the impulse turbine, the steam is expanding in the fixed nozzles. The high velocity
steam from the nozzles does work on the moving blades which cause to rotate the shaft.
The essential feature of an impulse turbine is that all pressure drops occur in nozzle
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only and there is no pressure drop in moving blade
8.3.2 Reaction Turbine
In this type, pressure is reduced in both fixed and moving blade. Both fixed and moving
blades act like nozzles and are of the same shape. Work is done by the impulse affect
due to the reversal of the direction of the high velocity steam plus a reaction affect due
to the expansion of the steam through the moving blades.
8.4 Classification of The Steam Turbine
Classification of the steam turbine is done on the basics of the following.
According to the direction of the flow
1. Axial turbine
2. Radial turbine
According to the principle of action of the steam
1. Impulse turbine
2. Reaction turbine.
According to the steam condition at inlet to turbine
1. Low pressure turbine
2. Medium pressure turbine
3. High pressure turbine
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CHAPTER 9
GENERATOR
9.1 Introduction
"An electrical generator is an electro mechanical machine which converts
mechanical energy into electrical energy"
Generator is the main part of a power plant. The generator has stator in gas cooling
construction enclosing the stator winding, core & hydrogen coolers. The cooling Medium
hydrogen is containing within the frame and circulation by fans mounted either at the ends
of the rotor .the generator is driven by directly coupled prime mover (steam turbine in
thermal plant)at constant speed of 3000rpm.
Provision has been made for circulating the cooling water in order to maintain a
constant temp of a coolant i.e. H2 as measured at the fan section side which is in touch with
the temp of the winding, core &other parts as per load.
All units have been provides with “Shandong Jinan Generating Equipment Ltd.”
make a 3-phase turbo generator. The generator mashes a closed loop of hydrogen gas
system for cooling the stator and rotor. Hydrogen gas at a pressure of 2atm is filled in a gas
tight outer closing of the generator. Hydrogen gas circulates inside the closing by two single
stage rotor mounted fans on either side of the rotor. The heated H2is in turn cooled by six
surface type water coolers axial mounted inside the generator casting. The cooled water is
supplied to H2 coolers from bcw overhead tank.
Each generator has terminal led out of its closing and a star point is formed
by sorting the neutral side’s terminal by a sorting bar. 1 phase 11000/220, 37.5KVa neutral
grounding X'mer whose secondary is laminated by laminated strip with mechanical
ventilating holes grounds the neutral.
9.2 Parts of Generator
1. Stator Body
The stator body is a totally enclosed gas tight fabricated structure suitable ribbed to rigidity.
It is designed mechanically to withstand internal pressure & forces as an event of unlikely
event of explosion of hydrogen &oil mixture withstand pressure .The function of stator
frame is to contain and support the stator core winding, hydrogen coolers and also path for
distribution of cooling hydrogen through the generator
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2. Stator Core
The rotating magnetic field flows with the core. In order to reduce the magnetizing (eddy)
current losses in the active portion of the stator core the entire core is built up of thin
lamination. The segments are stamped out from CRGO. The core contain several pockets
separated by steel spaces for radial cooling of the core
3. Stator Winding
The stator has 3-phase double layer short-pitched end bar type of winding having two
parallel paths. Each slot accommodates two bars. The lower & upper bar are displaced from
each other by one winding pitch and connected at their ends so as to form coil groups. Each
bar consists of solid as well as hollow conductors with cooling water passing through the
later alternator. Arrangement of hallows and solid conductor ensures an optimum solution
for increasing current and losses. The high voltage insulation is provided by thermo setting
insulator using mica paper type (Resin Rich)
4. Distillate Header
Ring type, water header made up of copper is provided separate for distillate inlet & outlet
in the stator of turbine side .The headers are support on insulator and insulated from stator
body. At turbine side each individual bas is connected with inlet/outlet header. The vent
pipe connection is at the top of the both inlet & outlet header .The vent pipes are connected
at gas trap desire to measure the extent of hydrogen leakage into water circuit.
5. Terminal Bushing
Three phases and six neutral terminals are brought out from the stator through bushing
which are capable of withstanding high voltage and provided with gas tight joints the
bushing is assembled and tested for flow, leakage to ensure tightness and continuous flow
of water.
6. End Shield
To make the stator body gas tight the end shield are fitted gas tightness is achieved by
putting a rubber sealing cord .The end shields are made in two halves convenience during
erection and installation.
36
7. Rotor
The rotor shaft is a single piece forging the longitudinal slot for inserting the field winding.
The slots are distributed over the circumference so that two field solid poles are obtained.
After completion of rotor assembly the rotor is balanced at different speed test at 120% of
rated speed for 2minuts the rotor conductor is of silver bearing copper. The field copper
current is supplied to the rotor winding through two semiconductor copper bars arranged
in hollow bars of rotor through radial current carrying bolts.
8. Bearing
The generator bearings are of pedestal type with spherical seating. It allows self-alignment
and supported on a separate pedestal on slip ring side. The bearing has a provision of
hydraulic shaft lifting during start up and turning gear operation to eliminate shaft current
shaft bearing and its pipes are insulated from earth.
9. Brush Gear
The current carrying gear assembly is rigidly fixed on the extent peat of the bearing pedestal
on the exciter side. There are two brushes gear stand for +tive and -tive supply. The field
to stator winding provides the brush gear. The brushes are loaded to maintain required
contact pressure of 0.2kg/cm2 and the brushes during normal operation condition have low
coefficient of friction and are self-lubricating.
Fig 9.1:-Cross Section View Generator
9.3 Starting of generator
To start the generator the following procedure is followed:
37
Generator field breakers should be opened.
Generator circuit breaker should be opened.
The shaft seal oil is system should be kept under the operation.
Hydrogen filling must be completed.
As generator is brought up to the speed .The following must be checked.
Oil pump delivery pressure and quantity of oil.
Oil leakage from bearing.
Mechanical balance by taking shaft variation.
1. The steady state temp of bearing and lubricating oil at rated speed must be checked.
2. The generator field breaker is closed and drying out of turbo generator is carried out.
3. Auto voltage regulator may be adjusted and the voltage adjusting unit on regulator may
set to get the desired voltage.
4. Inducing 130% of rated voltage& maintaining it for five minutes can test insulation of
stator winding.
5. Now generator is ready to be synchronized with system.
To synchronize the Generator with system below conditions must be satisfied:
Phase sequence must be same
Frequency must be same
Voltage generated must be same
9.4 Shutting down of generator
To shut down a generator we follow below procedure
Cut off load gradually from the machine and open generator C.B.
The switch for de excitation provides A.V.R is switched on.
The water to the hydrogen coolers and steam to turbine is to be cut off.
The speed of Generator is reduced to20-25 % of rated.
9.5 Excitation system
The electrical power requires D.C excited magnets for its field system. The excitation
system must be stable in operation and must respond quickly to excitation current
38
requirement. When excitation control is by a fast regulating or a supply is given from
transformer and then rectified.
The main function of excited system is to supply the required excitation current at the rated
load or any operating load condition. It should be able to adjust the field current of the
generator either by normal control or but automatic control so that for all operation between
known load and rated the terminal voltage of the synchronous machine is maintained at its
value.
9.6 Types of Excitation
There have been many developed in excitation system design and research is continuing.
The ultimate aim is to achieve one system idle in rate of response, simplicity, reliability
and accuracy. Excitation systems are:
Conventional DC system
Brushless excitation system
Static excitation system
9.7 Turbo Generator Specification
Specification
KVA 247000
PF 0.85
Volts of stator 15750
Amperes of stator 9050
Volts of rotor 310
Amperes of rotor 2600
RPM 3000
Frequency 50 Hz
Phase 3
Connection YY
Coolant water (stator) & hydrogen (rotor)
Gas pressure 3.5kg/cm-sq.
39
Insulation class B
40
CHAPTER 10
SWITCHYARD
10.1 Introduction
Switchyard is considered as the HEART of the Power Plant. Power generated can be worthy
only if it is successfully transmitted and received by its consumers. Switchyard plays a very
important role as a junction between the generation and transmission. It is a junction, which
carries the generated power to its destination (i.e. consumers) In BSTPP there are two
switchyards:-
(i) 400KV SWITCHYARD
(ii) 132KV SWITCHYARD
10.1.1 400 KV SWITCHYARD
There are total 22 bay in 400 KV switchyard. A Bay is basically a way for the incoming
power from generator as well as outgoing power for distribution.
5 Bay for each generating transformer
3 Bay for ICT(Inter Connecting Transformer)
2 Bay for PATNA line
2 Bay for KAHALGAON line
2 Bay for BALIA line
7 for FUTURE line
1 Bay for SHUNT REACTOR
There are four main buses in 400 KV switchyard.
Ø Main bus – 1& 2
Ø Main bus – 3&4
10.1.2 132 KV SWITCHYARD
There are total 11 Bay in 132 KV switchyard.
3 Bay for ICT (Inter Connecting Transformer)
5 Bay for S.T (Station Transformer)
2 Bay for MST (Miscellaneous Service Transformer)
1 Bay for Bus Coupler
41
There are two main buses in 132 KV switchyard.
Main bus - 1
Main bus - 2
10.2 Components of Switchyard
Fig 10.1:-Component of Switchyard
1. Insulator
The insulators mainly serve two purposes. First of all they support the conductor and
confined the high current of the line to the conductor. The most common material for the
manufacturing of insulators is Porcelain. Below mentioned are the types of Insulators used
in switchyard,
Pin Insulator
Post Type
Suspension Insulator
Strain Insulator
2. Bus bar
In electrical power distribution, a bus bar is a strip or bar of copper, brass or aluminum that
conducts electricity within a switchboard, distribution board, substation, battery bank, or
other electrical apparatus.
3. Lightning arrester
42
A lightning arrester is a device used on electrical power systems and telecommunications
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.
4. Wave trap
Wave Traps are used at sub-stations using Power Line Carrier Communication (PLCC).
PLCC is used to transmit communication and control information at a high frequency over
the power lines. This reduces need for a separate infra for communication between sub-
stations
5. Circuit 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 basic function is to
detect a fault condition and interrupt current flow.
6. Capacitive Voltage Transformer
A capacitor voltage transformer (CVT), or capacitance-coupled voltage transformer
(CCVT), is a transformer used in power systems to step down extra high voltage signals
and provide a low voltage signal, for metering or operating a protective relay
7. Current Transformer
Fig 10.2:-Connection of Current Transformer
The current transformer is a step up transformer , it means current is stepped down to a
very low value (generally 1 A or 5 A) so that it can be used for measuring and protection
43
purposes .C.T is designed in such a way its Core Material could give high accuracy with
low saturation factor. Core Material is generally made of CRGO Silicon steel for very low
loss characteristics, µ material (Alloy of Ni-Fe) is used. Current Transformer is used for
basically two major functions: -
1 .Metering:-which means current measurement.
2. Protection:-such as over current protection, overload earth fault protection, Bus-bar
protection, Bus differential protection. CT is typically described by its current ratio from
primary to secondary. There is not more difference between 132 KV and 400 KV C.T, only
current ratio differ
10.1. Specification of 132KV C.T
Standard IS2705
Highest System Voltage 145 KV
Insulation Level 275/650 KV
Frequency 50 HZ
Short Time Current 31.5 KA for 1 sec
Rated Primary Current 1200A
Extended Current 120
10.2. Specification of 400 KV C.T
Standard IS2705
Rated Voltage 420 KV
Insulation Level 275/650 KV
Frequency 50 Hz
Short Time Current 31.5 KA for 1 sec
Rated Continuous normal Current 2000 A
Extended Current 200/120%
Oil weight 750 kg
Total weight 2500 K
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8. Isolator
An isolator is one, which can break an electrical circuit when the circuit is to be switched
on no load. These are normally used in various circuits for the purposes of isolating a certain
portion when required for maintenance etc. It is always used in OFF-LOAD condition.
“Switching isolators" are capable of interrupting transformer magnetized currents;
interrupting line charging current; and Load transfer switching
9. Surge Arrester
This will protect the equipment from transient, surge and high voltages. They are generally
connected in parallel to the equipment to be protected and function to divert the surge
current safely to ground.
10. Earth switches on Isolator
Earth Switch is used to discharge the residual charge on the circuit to the earth safely. Earth
switch is mounted on the frame of the isolators. After the equipment is isolated then the
earth rod is connected so that the residual charges present on the device will be grounded.
This is mainly done for safeguarding human life from getting a shock.
11. Protective relay
Fig 10.3 cross section of relay
A protective relay is a device that detects the fault and initiates the Operation of the Circuit
breaker to isolate the faulty element from the rest of the system. The relay sense fault and
gives the command to the circuit breaker and the circuit breaker is operated. The relay
receives the command from the instruments transformers (i.e. CTs & PTs).
45
CHAPTER 11
TRANSFORMER
11.1 Introduction
It is a static machine which increases or decreases the AC voltage without changing the
frequency of the supply. It is a device that:
Transfers electric power from one circuit to another.
It accomplishes this by electromagnetic induction.
In this the two electric circuits are in mutual inductive influence of each other.
Transformer is made up of following parts:-
1. Core
2. Winding
3. On load tap changer
4. Conservator tank
5. Brushing
6. Auxiliary equipment’s
7. Cooling system
Fig:-11.1 Cross Section View Transformer
46
1. Core
It is an essential feature of power transformer. Magnetic circuit is three-limb core type
construction. Each limb has interleaved points with top & bottom yoke. The three limbs
have winding. The lamination are made up of high grade none aging, cold rolled grain
oriented silicon steel. This yolk are clamped by mean of bolts and nuts .The tapping leads
are connected on tap changer which is mounted outside the transformer.
2. Winding
The inner most coil near the core term low voltage winding. This is spiral Coil. Axial coil
ducts are provided inside and the coil. Outside it is the high voltage winding. These are also
disc type winding provided with axial and radial ducts. Line load is taken out from top of
coil. Static rings have been provided and the line ends of H.V coil for better impulse
distribution across the coil.
3. On Load Tap Changer
An on load tap changer is a device used for changing the taping connection of winding
Suitable for operation while the X'mer is energized on load. The tap changer is a operated
by a motor operated driving m/c by load or remote control and a handle is fined for manual
operation in any emergency tank bodies for transformer are made from rolled steel plates
which is fabricated to from the container.
4. Conservator Tank
Conservator tank is of steel plate .it is designed to withstand a vacuum pressure of 755mm.
They also made of rolled steel, which is fabricated to form one container. Internal fitting
and clamps is poisoned and welded internally small transformer, which have cooling tubes.
Such transformers, have plane tank with provision for pipe and valves to direct and control
the oil flow.
5. Brushing
When transformer has been connected to high voltage line care must be taken to prevent
flashover one H.V connection to earthed tank. This is done by means of bushing. The
simplest bushing is a molded high quality glazed porcelain insulated with the conductor
through its center these bushing can be used up to 33KV
47
6. Cooling System
The losses in any transformer can be of the order of several hundred KW and the efficiency
will be about 90.5% on full load to prevent deterioration of insulation due to temperature.
This waste heat must be dissipated by carefully designing the cooling system. The losses
comprise of copper losses, hysterics losses and eddy current losses. In large transformer the
usual method of exciting the heat from the core subsequently cooled by another means of
radiator over which circulation by natural convection air is blown. The later be known as
air blast cooling to assist in cooling most large unit have forced oil circulation .The oil have
been pumped through transformer & cooling tubes.
11.2 Classification
(I) According To Core
a) Core type transformer
b) Shell type transformer
c) Berry type transformer
(II) According To phases
a) 1-phase transformer
b) 3-phase transformer
(III) According to the purpose for which used
a) Distribution transformer
b) Transmission transformer
c) Generator transformer
d) Station transformer
e) Unit Auxiliary transformer (UAT)
11.3 Generating Transformer
48
Fig 11.2:-Generator transformer
A generating transformer is a single – phase power transformer (3 single phase units shall
form a bank). Generating Transformer steps–up the generated voltage of 24 KV by
alternator to a higher voltage of 400 KV (hence, working as a step-up Transformer).This
voltage of 400 KV is then transmitted to switchyard
Specification
HV Nominal Voltage 420/sqrt (3) KV
LV Nominal Voltage 24 KV
Rated Power 260 MVA
HV Nominal Current 1072.22 A
LV Nominal Current 10833.33 A
Frequency 50 Hz
Lightning impulse withstand voltage 1425 kVp(HV)170 kVp(LV)95 kVp(HV)
Tap range ± 5% in steps of 2.5%on HV neutral side
Oil weight 60430 Kg
Total weight 250930K
11.4 Inter Connecting Transformer
An ICT is a 3-phase auto transformer used to interconnect 400 KV switchyard and 132 KV
switchyard
49
Specification
Standard IS: 2026
Type Auto Transformer
Rated power 200 MVA (HV) 200 MVA (MV) 67 MVA (LV)
Current rating of different cooling 40% /60%/100% (A)
Core and winding mass 115600 Kgs
Oil mass 81880 Kgs
Total oil quantity 92000 liter
11.5 Station transformer
Station Transformer is used only for initializing the start-up of the station (Main Plant).It
is very beneficial during emergency situations such as tripping of Units, shut-down
etc.Station transformers is used to start
Station auxiliaries are required for generating services such as coal and ash handling
system, lighting system, water purifying system etc. It gets the supply in its primary from
132 KV switchyard, steps down it to 11.5KV which is used for starting various equipment’s
& devices used in the Main power plant
Specification
Standard IS: 2026/77-81
Type Three Winding
Rated output 90/45/45 MVA
Cooling ONAN/ONAF
Rated voltage 132 KV (HV) 11.5 KV (LV1 & LV2)
Core & coil mass 60500 Kg
Oil quantity 33700 Liter
Total mass 121500 K
11.6 Unit Transformer
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Unit transformer is directly coupled to the unit itself so when that unit is in running
condition it supplies power to which are coupled to auxiliaries directly or through unit
auxiliary transformer depending upon load. Unit auxiliaries are those which are directly
associated with the generating unit such as ID and FD fans, Boiler feed pumps, coal mills,
fans, circulating water pumps etc.
Specification
Rated output 35 MVA
Cooling ONAN/ONAF
Voltage ratio 24 / 11.5 KV
Frequency 50 Hz
Phases 3
ONAN rating in 80% of rated MVA
11.7 Miscellaneous Service transformer
Miscellaneous service transformer are used to supply miscellaneous loads of plant. It is a
two winding transformer connected to 132 KV switchyard.
Specification
Standard IS: 2026 /77-81
Rated output 16 MVA
Full load rated current 69.98 A803.27 A
Cooling ONAN
Type Two winding
Voltage ratio 132 / 11.5 KV
Frequency 50 Hz
Phase Three
Core & coil mass 17650 Kg
Oil quantity 10400 liter
Total mass 37600 kg
51
CONCLUSION
On the completing of my vocational training at Thermal Power Station
BARH, I have come to know about how the very necessity of our life
nowadays i.e. Electricity is Generated. What all the processes are needed to
generate and run the power plant on 24X7 basis.
Water and air are the most precious in the world so we have to save these
things by recycling water or decreasing pollution.
Training gave me an opportunity to clean my concepts from practical point of
view with the availability of the machinery of such larger rate.
Finally as my industrial training came to an end, I felt that this
additional knowledge and exposure would certainly help me mould career
in the technical field and would also give us that extra bit of advantage and
recognition required to enhance my profile.
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REFERENCES
http://www.ntpc.co.in
https://en.wikipedia.org/wiki/Barh_Super_Thermal_Power_Station
http://www.electrical4u.com