Power plant overview_2

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POWER GENERATION AND

MAINTAINANCE

By

D.SRAVAN (314126514036)

E.SIVA SHANKAR (314126514041)

G.NARENDRA (314126514044)

G.G.CHAITANYA (314126514045)

PERIOD: 30/5/2016 to 13/06/2016

DATE:13/06/2016

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CERTIFICATE

ELECTRICAL MAINTAINANCE DEPARTMENT

SIMHADRI SUPER THERMAL POWER STATION

NTPC -VISAKHAPATNAM

This is to certify that the project work entitled

POWER GENERATION AND MAINTAINANCE

is a bonafide record of the work done by

D.SRAVAN (314126514036)

E.SIVA SHANKAR(314126514041)

G.NARENDRA (314126514044)

G.G.CHAITANYA (314126514045)

of Department of ELECTRICAL and ELECTRONICS Engineering, Anil

Neerukonda Institute of Technology and Sciences, affiliated to

Andhra University (AU), Visakhapatnam. They did this project

work under my supervision and guidance in partial fulfilment of

the requirement for the award of grade points in INDUSTRIAL

TRAINING, 2/4 - B.E,III- semester.

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SHRI

VIJAYA KUMAR,

DEPUTY GENERAL MANAGER (E.M),

NTPC SIMHADRI.

CERTIFICATE



NTPC -VISAKHAPATNAM



is a bonafide record of the work done by D.SRAVAN

(314126514036)of Department of ELECTRICAL and ELECTRONICS

Engineering, Anil Neerukonda Institute of Technology and

Sciences, affiliated to Andhra University (AU), Visakhapatnam. He

did this project work under my supervision and guidance in

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partial fulfilment of the requirement for the award of grade points

in INDUSTRIAL TRAINING, 2/4 - B.E, III- semester.

SHRI VIJAYA KUMAR,


NTPC SIMHADRI.

of 95

CERTIFICATE



NTPC -VISAKHAPATNAM



is a bonafide record of the work done by E.SIVA SHANKAR

(314126514041) of Department of ELECTRICAL and ELECTRONICS





in INDUSTRIAL TRAINING, 2 /4 - B.E, III-semester.

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SHRI VIJAYA KUMAR,


NTPC SIMHADRI.

of 95

CERTIFICATE



NTPC -VISAKHAPATNAM



is a bonafide record of the work done by G.NARENDRA







of 95

SHRI VIJAYA KUMAR,


NTPC SIMHADRI.

of 95

CERTIFICATE



NTPC -VISAKHAPATNAM



is a bona fide record of the work done by G.G.CHAITANYA







of 95

SHRI VIJAYA KUMAR,


NTPC SIMHADRI.

ACKNOWLEDGEMENT

My sincere thanks to our guide SHRI VIJAYA KUMAR , DEPUTY

GENERAL MANAGER (Electrical Maintenance), NTPC Simhadri for

his continuous help, encouragement and involvement in my mini

project.

With profound respect and gratitude, we take the opportunity to

convey thanks for permitting us to complete our training here.

We are extremely grateful to all the technical staff of STPP / NTPC

for their co-operation and guidance that has helped us a lot

during the course of training. We have learnt a lot working under

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them and we will always be indebted to them for this value

addition in us.

We would also like to thank H.O.D. of ANITS ENGINEERING

COLLLEGE and all the faculty members of electrical department

for their effort of constant co-operation, which have been a

significant factor in the accomplishment of our industrial training.

NTPC Overview

NTPC is India’s largest energy conglomerate with roots planted

way back in 1975 to accelerate power development in India. Since

then it has established itself as the dominant power major with

presence in the entire value chain of the power generation

business. From fossil fuels it has forayed into generating

electricity via hydro, nuclear and renewable energy sources. This

foray will play a major role in lowering its carbon footprint by

reducing green house gas emissions. To strengthen its core

business, the corporation has diversified into the fields of

consultancy, power trading, training of power professionals, rural

electrification, ash utilisation and coal mining as well.

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NTPC became a Maharatna company in May 2010, one of the only

four companies to be awarded this status. NTPC was ranked

400th in the ‘2016, Forbes Global 2000’ ranking of the World’s

biggest companies.

Growth of NTPC installed capacity and generation

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The total installed capacity of the company is 47,178 MW

(including JVs) with 18 coal based, 7 gas based stations and 1

Hydro based station. 9 Joint Venture stations are coal based and 9

renewable energy projects. The capacity will have a diversified

fuel mix and by 2032, non fossil fuel based generation capacity

shall make up nearly 28% of NTPC’s portfolio.

NTPC has been operating its plants at high efficiency levels.

Although the company has 17.73% of the total national capacity,

it contributes 24% of total power generation due to its focus on

high efficiency.

In October 2004, NTPC launched its Initial Public Offering (IPO)

consisting of 5.25% as fresh issue and 5.25% as offer for sale by

the Government of India. NTPC thus became a listed company in

November 2004 with the Government holding 89.5% of the equity

share capital. In February 2010, the Shareholding of Government

of India was reduced from 89.5% to 84.5% through a further

public offer. Government of India has further divested 9.5%

shares through OFS route in February 2013. With this, GOI's

holding in NTPC has reduced from 84.5% to 75%. The rest is held

by Institutional Investors, banks and Public.

NTPC is not only the foremost power generator; it is also among

the great places to work. The company is guided by the “People

before Plant Load Factor” mantra which is the template for all its

human resource related policies. NTPC has been ranked as “6th

Best Company to work for in India” among the Public Sector

Undertakings and Large Enterprises for the year 2014, by the

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Great Places to Work Institute, India Chapter in collaboration with

The Economic Times.

Vision and Mission

Vision

“To be the world’s largest and best power producer, powering

India’s growth”.

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Mission

“Develop and provide reliable power, related products and

services at competitive prices, integrating multiple energy sources

with innovative and eco-friendly technologies and contribute to

society”.

NTPC OBJECTIVE

Business portfolio growth

Customer Focus

Agile Corporation

Performance Leadership

Human Resource Development

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Financial Soundness

Sustainable Power Development

Research and Development

Core Values – BE COMMITTED

B Business Ethics.

E Environmentally & Economically Sustainable.

C Customer Focus.

O Organisational & Professional Pride.

M Mutual Respect & Trust.

M Motivating Self & others.

I Innovation & Speed.

T Total Quality for Excellence.

CONTENTS

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CHAPTER 1 ........................................................................................................ 23

NATIONAL THERMAL POWER CORPORATION (NTPC Ltd.)................. 23

1.1 INTRODUTION:........................................................................... 23

1.2 POWER STATIONS OF NTPC: .................................................... 24

1.2.1 Thermal Based Stations ........................................................ 24

1.2.2 Gas based stations: ............................................................... 27

1.2.3 Hydro based stations: ........................................................... 28

CHAPTER 2 ........................................................................................................ 29

POWER PLANTS .......................................................................................... 29

2.1 Types of Power Plants .............................................................. 29

A. CONVENTIONAL PLANTS: ................................................................................... 29

i. THERMAL POWER PLANTS: ................................................................................. 29

ii. HYDAL POWER PLANTS: ...................................................................................... 29

iii. NUCLEAR POWER PLANTS: ................................................................................. 30

B. NON CONVENTIONAL PLANTS: ......................................................................... 30

i. SOLAR PLANTS: .................................................................................................... 30

a) SOLAR PHOTO VOLTAICS (PV): .......................................................................... 30

b) SOLAR THERMAL PLANTS: .................................................................................. 30

ii. WIND POWER PLANTS: ........................................................................................ 30

CHAPTER 3 ........................................................................................................ 32

SIMHADRI SUPER THERMAL POWER PROJECT (STPP) .......................... 32

3.1 INTRODUCTION ......................................................................... 32

3.2 GEOGRAPHY: .............................................................................. 32

3.3 UNITS OF STPP: .......................................................................... 32

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3.4 RESOURCES: ................................................................................ 33

A. WATER: .................................................................................................................. 33

B. COAL: .................................................................................................................... 34

3.5 CUSTOMERS:............................................................................... 34

3.6 UNIQUE FEATURES:.................................................................... 34

3.7 PROCESS SCHEME OF POWER PLANT: .................................... 35

CHAPTER 4 ........................................................................................................ 38

POWER PLANT EQUIPMENT...................................................................... 38

4.1 CLASSIFICATION ........................................................................ 38

CHAPTER 5 ........................................................................................................ 40

BOILER & AUXILIARIES .............................................................................. 40

4.2 BOILER ......................................................................................... 40

4.3 BOILER TYPES ............................................................................. 40

4.4 CONTROLLING DRAFT: ............................................................. 41

4.5 BOILER EQUIPMENT ................................................................... 43

A) Super Heaters: ......................................................................................................... 44

B) Re-Heaters: ............................................................................................................. 44

C) Economizer:............................................................................................................. 45

4.6 BOILER AUXILIARIES .................................................................. 45

A) Coal Firing System:................................................................................................... 46

B) Coal Burners: ........................................................................................................... 47

C) AIR PRE HEATER (APH) ............................................................................................. 47

CHAPTER 6 ........................................................................................................ 50

TURBINE & AUXILIARIES ........................................................................... 50

6.1 TURBINE ...................................................................................... 50

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6.2 TYPES OF TURBINE .................................................................... 51

6.3 STAGES OF TURBINE ................................................................. 53

A) High Pressure (HP) Turbine: ..................................................................................... 53

B) Intermediate Pressure (IP) Turbine:.......................................................................... 54

C) Low Pressure (LP) Turbine: ................................................................................ 54

6.4 TURBINE EQUIPMENT ................................................................ 55

A) CONDENSER ............................................................................................................ 55

B) Low Pressure heater: ............................................................................................... 57

C) DEAERATOR............................................................................................................. 59

6.5 TURBINE AUXILIARIES................................................................ 60

A) BOILER FEED WATER PUMP...................................................................................... 61

CHAPTER 7 ........................................................................................................ 63

GENERATOR ............................................................................................... 63

7.1 TECHNICAL SPECIFICATION ..................................................... 63

7.2 CONSTRUCTION......................................................................... 64

A) STATOR ................................................................................................................... 64

B) ROTOR .................................................................................................................... 65

C) STATOR WINDING.................................................................................................... 66

D) ROTOR WINDING ..................................................................................................... 66

E) TEMPERATURE RISES ............................................................................................... 67

F) WINDING TEMPERATURE MONITORING ................................................................... 68

G) VENTILATION & COOLING ........................................................................................ 68

H) COOLANT TEMPERATURE CONTROL .......................................................................... 69

I) SEAL OIL SYSTEM (DOUBLE FLOW SEAL).................................................................... 70

J) PRIMARY WATER SYSTEM ........................................................................................ 71

K) BEARING AND SHAFT SEALS ..................................................................................... 71

L) HYDROGEN GAS COOLERS ........................................................................................ 72

M) PRIMARY WATER TREATMENT SYSTEM..................................................................... 72

N) STATOR WINDING HOLLOW COPPER CORROSION..................................................... 73

O) Generator& Auxiliaries ............................................................................................ 74

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CHAPTER 8 ........................................................................................................ 75

TRANSFORMERS ........................................................................................ 75

8.1 INTRODUCTION ......................................................................... 75

8.2 GENERATOR TRANSFORMER (GT) ........................................... 76

8.3 UNIT TRANSFORMERS (UT) ...................................................... 77

8.4 STANDBY TRANSFORMER (ST)................................................. 78

8.5 DG SETS....................................................................................... 79

CHAPTER 9 ........................................................................................................ 80

OFFSITE AREAS .......................................................................................... 80

9.1 WATER SYSTEM .......................................................................... 80

A) Sea water pump house:........................................................................................ 80

B) CW system:.............................................................................................................. 80

C) Cooling Towers: ....................................................................................................... 81

D) Sweet Water Pump House:................................................................................... 81

E) Pre Treatment and DM Plant.................................................................................... 82

9.2 COAL HANDLING PLANT: ......................................................... 83

9.3 ASH HANDLING PLANT ............................................................. 83

9.4 FUEL OIL PUMP HOUSE ............................................................. 84

9.5 H2 PLANT .................................................................................... 84

CHAPTER 10 ...................................................................................................... 85

SWITCHYARD ............................................................................................. 85

10.1 INTRODUCTION ...................................................................... 85

10.2 MAIN EQUIPMENTS USED IN SWITCH YARD:...................... 86

A) Bus bars: ................................................................................................................. 86

B) Solid Core Post Insulator .......................................................................................... 86

C) Capacitor Voltage Transformer (CVT): ...................................................................... 87

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D) CURRENT TRANSFORMERS (CT): ............................................................................... 87

E) SURGE ARRESTERS (SA): ........................................................................................... 88

F) ISOLATORS AND EARTH SWITCHES: .......................................................................... 89

G) CIRCUIT BREAKERS:.................................................................................................. 90

H) Overhead earth wire: ............................................................................................... 92

I) Reactive power control devices: ............................................................................... 92

J) Current Limiting Reactors:........................................................................................ 92

K) Batteries:................................................................................................................. 93

CONCLUSION .................................................................................................... 94

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CHAPTER 1

NATIONAL THERMAL POWER CORPORATION (NTPC Ltd.)

1.1 INTRODUTION:

NTPC Limited (formerly National Thermal Power

Corporation) (BSE: 532555, NSE: NTPC) which is founded

on 7 November 1975, is the largest Indian state-owned

electric utilities company based in New Delhi, India.

NTPC is a Maharatna Status Company with a total installed

capacity of 43,039 MW (including Joint Ventures) with 17

coal based and 7 gas based stations, located across the

country. In addition, under JVs (Joint Venture), 7 stations

are coal-based, and another station uses naphtha/LNG as

fuel.

It is listed in Forbes Global 2000 for 2014 at 424th rank

in the world.

By 2017, the power generation portfolio is expected to

have a diversified fuel mix with coal based capacity of

http://en.wikipedia.org/wiki/Bombay_Stock_Exchange

http://www.bseindia.com/bseplus/StockReach/AdvanceStockReach.aspx?scripcode=532555

http://en.wikipedia.org/wiki/National_Stock_Exchange_of_India

http://www.nseindia.com/marketinfo/companyinfo/companysearch.jsp?cons=NTPC&section=7

http://en.wikipedia.org/wiki/Electric_utilities

http://en.wikipedia.org/wiki/Maharatna

http://en.wikipedia.org/wiki/Forbes_Global_2000

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around 27,535 MW, 3,955 MW through gas, 1,328 MW

through Hydro generation, about 1400 MW from nuclear

sources and around 1000 MW from Renewable Energy

Sources (RES).

The company has 18% of the total national capacity it

contributes 27% of total power generation due to its focus

on high efficiency.

Every fourth home in India is lit by NTPC.

NTPC is lighting every third bulb in India.

1.2 POWER STATIONS OF NTPC :

1.2.1 Thermal Based Stations

Sr.

No. Project State Capacity Units Status

1

Singrauli Super

Thermal Power

Station

Uttar

Pradesh 2,000

5x200 MW, 2x500

MW All units functional

2 NTPC Korba Chhattisg

arh 2,600

3x200 MW, 4x500


3 NTPC

Ramagundam

Andhra

Pradesh 2,600

3x200 MW, 4x500


http://en.wikipedia.org/wiki/Singrauli_Super_Thermal_Power_Station



http://en.wikipedia.org/wiki/Uttar_Pradesh


http://en.wikipedia.org/wiki/NTPC_Korba

http://en.wikipedia.org/wiki/Chhattisgarh


http://en.wikipedia.org/wiki/NTPC_Ramagundam

http://en.wikipedia.org/wiki/NTPC_Ramagundam

http://en.wikipedia.org/wiki/Andhra_Pradesh


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Sr.


4

Farakka Super

Thermal Power

Station

West

Bengal 2,100

3x200 MW, 3x500


5 NTPC

Vindhyachal

Madhya

Pradesh 4,260

6x210 MW, 6x500


6 Rihand Thermal

Power Station

Uttar

Pradesh 3,000 6x500 MW All units functional

7

Kahalgaon

Super Thermal

Power Station

Bihar 2,340 4x210 MW, 3x500


8 NTPC Dadri Uttar

Pradesh 1,820

4x210 MW, 2x490


9 NTPC

TalcherKaniha Orissa 3,000 6x500 MW All units functional

10

Feroze Gandhi

Unchahar

Thermal Power

Plant

Uttar

Pradesh 1,050 5x210 MW All units functional

11 Talcher Thermal

Power Station Orissa 460

4x60 MW, 2x110


12 Simhadri Super

Thermal Power Andhra

2000 4x500 MW All units functional

http://en.wikipedia.org/wiki/Farakka_Super_Thermal_Power_Station



http://en.wikipedia.org/wiki/West_Bengal

http://en.wikipedia.org/wiki/West_Bengal

http://en.wikipedia.org/wiki/NTPC_Vindhyachal

http://en.wikipedia.org/wiki/NTPC_Vindhyachal

http://en.wikipedia.org/wiki/Madhya_Pradesh

http://en.wikipedia.org/wiki/Madhya_Pradesh

http://en.wikipedia.org/wiki/Rihand_Thermal_Power_Station

http://en.wikipedia.org/wiki/Rihand_Thermal_Power_Station



http://en.wikipedia.org/wiki/Kahalgaon_Super_Thermal_Power_Station



http://en.wikipedia.org/wiki/Bihar

http://en.wikipedia.org/wiki/NTPC_Dadri



http://en.wikipedia.org/wiki/NTPC_Talcher_Kaniha

http://en.wikipedia.org/wiki/NTPC_Talcher_Kaniha

http://en.wikipedia.org/wiki/Orissa

http://en.wikipedia.org/wiki/Feroze_Gandhi_Unchahar_Thermal_Power_Plant






http://en.wikipedia.org/wiki/Talcher_Thermal_Power_Station

http://en.wikipedia.org/wiki/Talcher_Thermal_Power_Station

http://en.wikipedia.org/wiki/Orissa

http://en.wikipedia.org/wiki/Simhadri_Super_Thermal_Power_Plant



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Sr.


Plant Pradesh

13 Tanda Thermal

Power Plant

Uttar

Pradesh 440 4x110 MW All units functional

14

Badarpur

Thermal Power

Station

Delhi 705 3x95 MW, 2x210


15 Sipat Thermal

Power Plant

Chhattisg

arh 2980

2x500 MW, 3x660


16

Mauda Super

Thermal Power

Station

Maharasht

ra 1000 2x500 MW

All units

functional [12]

17

Barh Super

Thermal Power

Station

Bihar 1980 3x660

(1x660 MW)

Running, two more

units of 660 MW

under

construction[13]

18

Kudgi Super

Thermal Power

Project

Karnataka 2400 MW 3x800 MW

Under construction.

One unit is

expected to be

commissioned by

2015 December.[14]

19 NTPC

Bongaigaon Assam 750 MW 3x250 MW

Under construction.

One unit is

expected to be



http://en.wikipedia.org/wiki/Tanda_Thermal_Power_Plant

http://en.wikipedia.org/wiki/Tanda_Thermal_Power_Plant



http://en.wikipedia.org/wiki/Badarpur_Thermal_Power_Station



http://en.wikipedia.org/wiki/Delhi

http://en.wikipedia.org/wiki/Sipat_Thermal_Power_Plant

http://en.wikipedia.org/wiki/Sipat_Thermal_Power_Plant



http://en.wikipedia.org/wiki/Mauda_Super_Thermal_Power_Station



http://en.wikipedia.org/wiki/Maharashtra

http://en.wikipedia.org/wiki/Maharashtra

http://en.wikipedia.org/wiki/Barh_Super_Thermal_Power_Station



http://en.wikipedia.org/wiki/Bihar

http://en.wikipedia.org/wiki/Kudgi_Super_Thermal_Power_Project



http://en.wikipedia.org/wiki/Karnataka

http://en.wikipedia.org/wiki/NTPC_Bongaigaon

http://en.wikipedia.org/wiki/NTPC_Bongaigaon

http://en.wikipedia.org/wiki/Assam

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Sr.


commissioned in

2014.[15]

20

LARA Super

Thermal Power

Project

Chhattisg

arh 4000 MW

2x800+3x800(Sta

ge-I +Stage-II)

MW

Under construction.

One unit is

expected to be

commissioned by

2015 December.

[16]

1.2.2 Gas based stations :

Sr. No. Project State Installed Capacity in

Megawatt

1 NTPC Anta Rajasthan – Kota 413

2 NTPC Auraiya Uttar Pradesh 652

3 NTPC Kawas Gujarat 645

4 NTPC Dadri Uttar Pradesh 817

5 NTPC Jhanor Gujarat 648

6 NTPC

Kayamkulam Kerala 350

http://en.wikipedia.org/w/index.php?title=LARA_Super_Thermal_Power_Project&action=edit&redlink=1





http://en.wikipedia.org/wiki/NTPC_Anta

http://en.wikipedia.org/wiki/Rajasthan

http://en.wikipedia.org/wiki/NTPC_Auraiya


http://en.wikipedia.org/wiki/NTPC_Kawas

http://en.wikipedia.org/wiki/Gujarat

http://en.wikipedia.org/wiki/NTPC_Dadri


http://en.wikipedia.org/wiki/NTPC_Jhanor

http://en.wikipedia.org/wiki/Gujarat

http://en.wikipedia.org/wiki/NTPC_Kayamkulam

http://en.wikipedia.org/wiki/NTPC_Kayamkulam

http://en.wikipedia.org/wiki/Kerala

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Sr. No. Project State Installed Capacity in

Megawatt

7 NTPC

Faridabad Haryana 430

8 RGPPL Ratnagiri Maharashtra-

Ratnagiri 1967

1.2.3 Hydro based stations:

S.No Project State Installed

Capacity in

Megawatt

1 Loharinag Pala Hydro Power

Project

Uttarakhand state 600

2 TapovanVishnugad Joshimath town 520

3 LataTapovan upstream to Joshimath 130

4. Koldam Dam Himachal Pradesh 800

--*--*--

http://en.wikipedia.org/wiki/NTPC_Faridabad

http://en.wikipedia.org/wiki/NTPC_Faridabad

http://en.wikipedia.org/wiki/Haryana

http://en.wikipedia.org/w/index.php?title=RGPPL_Ratnagiri&action=edit&redlink=1

http://en.wikipedia.org/wiki/Loharinag_Pala_Hydro_Power_Project

http://en.wikipedia.org/wiki/Loharinag_Pala_Hydro_Power_Project

http://en.wikipedia.org/wiki/Koldam_Dam

http://en.wikipedia.org/wiki/Himachal_Pradesh

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CHAPTER 2

POWER PLANTS

2.1 Types of Power Plants

Power plants can be broadly categorized based upon the

resource, as follows:

A. CONVENTIONAL PLANTS:

These plants operate on the resources that do not have the

capacity to renew on their own.

i. THERMAL POWER PLANTS:

The input to the power production is the coal which

serves as the fuel for the conversion of the feed water

into the steam, which is propelled onto the turbine.

The inputs for a thermal power plant are:

water, which is being converted into steam the

working fluid of the power plant

coal is ignited for the conversion of the water into

steam

fuel oil is used to ignite the coal at the initial stages

of firing of the coal

ii. HYDAL POWER PLANTS:

The energy in the water which is present at some head is

used to rotate the turbine, which is coupled to the

generator for the electric power generation.

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iii. NUCLEAR POWER PLANTS:

The energy obtained by the chemical reactions of

radioactive elements is used to convert the water into

steam which is propelled onto the turbine.

B. NON CONVENTIONAL PLANTS:

Power plants utilize renewable energy resources which have

the capacity of renewing on their own on earth.

i. SOLAR PLANTS:

a) SOLAR PHOTO VOLTAICS (PV):

Electricity is produced from the solar energy by

photovoltaic solar cells, which convert the solar

energy directly to electricity. The dc power

generated from the PV cells is converted to ac with

the application of power electronic converters. These

Solar PV plants can either be grid connected or off-

grid type.

b) SOLAR THERMAL PLANTS:

Solar concentrators are used to receive solar energy

and are used to heat the oil flow through a set of

pipes, which in turn heat the water into steam in a

boiler and the steam generated is further used to

run the turbine.

ii. WIND POWER PLANTS:

The potential in the winds is being harnessed by placing

the wind turbines in the large scale commonly called as

wind farms.

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--*--*--

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CHAPTER 3

SIMHADRI SUPER THERMAL POWER PROJECT (STPP)

3.1 INTRODUCTION

Simhadri is the ambitious project of the NTPC intended to

provide the ever growing power needs of the state of Andhra

Pradesh.

STPP comes to the rescue of about 20 million units of power

consumed every day in Andhra Pradesh.

3.2 GEOGRAPHY:

The Project was developed near Parawada and 3384 acres of

land was allocated for the construction of the Thermal plant.

The site is located between the latitude 17°35’ to 17° 37’north

and longitude 83°05’ to 83°8’E.

3.3 UNITS OF STPP:

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STPP constitutes four operational units (each of 500MW).

Stage#1 includes Unit 1 & 2 and Stage#2 includes Unit 3 & 4.

Unit wise details along with commissioned date are tabulated

in the table below.

Stag

e

Unit

Numb

er

Installed

Capacity

(MW)

Date of

Commissioning

1st 1 500 2002 February

1st 2 500 2004 August

2nd 3 500 2011 March

2nd 4 500 2012 March

3.4 RESOURCES:

A. WATER:

The water intake for the project for cooling is done by sea

water drawn from 8.9 kms away from the Bay of Bengal

through an intake-well sized 9100 cubic meters. This

intake-well is again the biggest well-constructed in the

entire India. The project also gets Sweet water from the

Yeluru canal.

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B. COAL:

The plant receives the coal from talcher, singareni and

mahanadhi coal fields and also the imported coal from

Indonesia. The imported coal is of high GCV when compared

to the native coal fields. The Coal for the project will be

coming to the plan with a special rail line setup. The Coal

transport for the NTPC Simhadri Project has begun in

December 2002.

3.5 CUSTOMERS:

The produced power by the stage#1 is utilized by state of

Andhra Pradesh. The 85% of the power generated by the

stage#2 will be utilized by AP and the remaining 15% is given

to the central power grid.

3.6 UNIQUE FEATURES:

FIRST coastal based coal fired thermal power project of

NTPC

Biggest sea water intake-well in India (for drawing sea water

fro, bay of Bengal)

Use of sea water for condenser cooling and ash disposal

Asia’s tallest natural cooling towers (165 mts)6th in the

world

Use of fly ash bricks in the construction of all buildings

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Coal based project of ntpc whose entire power is allocated

to home state (AP)

Use of monitors as man machine interface (MMI’s) for

operating the plant

Use of the distributed digital control and management

information systems (DDCMIS)

Totally spring loaded floating foundation for all major

equipment including TG

Use of INERGEN as fire protection system for the 1st time in

NTPC

Flame analysis of boiler by dedicated scanners for all coal

burners the height of the Chimney is 275-feet - a record in

Asia for being the tallest factory chimney. Near to this are

the 165-meter two cooling towers.

3.7 PROCESS SCHEME OF POWER PLANT:

The process scheme of the power plant is shown below.

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Generation of electricity comprises various processes listed

below.

Coal cycle

Water to steam cycle

Flue gas cycle

Electricity cycle

Ash cycle

The Overview Diagram of The Stage#1’s Unit I is given below,

showing all process parameters.

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--*--*--

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CHAPTER 4

POWER PLANT EQUIPMENT

4.1 CLASSIFICATION

Equipment in the power plant can be broadly classified into

A. Main plant equipment

I. Boiler & Boiler auxiliaries

II. Turbine & Turbine auxiliaries

III. Generator & Generator auxiliaries

IV. Transformers & transformer auxiliaries

B. Station common equipment

I. Switchyard

II. H2 plant

C. Offsite area equipment

I. Coal Handling Plant (CHP)

II. Ash handling system

a. Ash water system

b.Ash Extraction system

c. Ash water recirculation

III. De-mineralized/ Pre-treatment Water Plant

(DMPT)

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IV. Fuel Oil Pump House (FOPH)

V. Fire Water Pump House (FWPH)

The equipment in power plant is described in the following

chapters.

--*--*--

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CHAPTER 5

BOILER & AUXILIARIES

4.2 BOILER

A boiler is a closed vessel in which water or fluid is heated.

The heated or vaporized fluid exits the boiler for use in

various processes or heating applications.

4.3 BOILER TYPES

Boilers are of mainly two types

Fire tube boilers

Water tube boilers.

Fire tube boilers:

Here water partially fills a boiler barrel with a small volume

left above to accommodate the steam. The heat source is

inside a furnace or a fire box that has to be kept permanently

surrounded by the water in order to maintain the temperature

of the heating surface just below the boiling point. The

furnace can be situated at one of the fire tube which

lengthens the path of hot gases, thus augmenting the heating

surface which can be further increased by making the gases

reversed direction through a second parallel tube or bundle

of multiple tubes (two-pass or return flue boiler).

Alternatively the gases may be taken along the sides and then

beneath the boiler through flues. In the case of a locomotive

boiler a boiler barrel extends from the fire box and the hot

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gases passes through a bundle of fire tubes inside the barrel

which greatly increases the heating surface compared to a

single tube and further improves heat transfer. Fire tube

boilers usually have a comparatively low rate of steam

production, but high steam storage capacity. Fire tube boilers

mostly burn solid fuels, but are readily adaptable to those of

liquid or gas variety.

Water tube boilers:

In this type the water tubes are arranged inside a furnace in a

number of possible configurations. Often the water tubes

connect large drums, the lower half portion of the drum

contains water and the upper half contains steam. In other

cases such as mono-tube boilers water is circulated by a

pump through a succession of coils. This type generally gives

high steam production rates, but less storage capacity than

the above. Water tube boilers can be designed to exploit any

heat source including nuclear fission and are generally

preferred in high-pressure applications, since the high-

pressure water or steam is contained within narrow pipes

which can withstand the pressure within a thinner wall.

4.4 CONTROLLING DRAFT:

Most boilers now depend on mechanical draft equipment

rather than natural draft. This is because the natural draft is

subjected to outside air conditions and temperature of flue

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gases leaving the furnace, as well the chimney height. All

these factors make proper draft hard to attain and therefore

make mechanical draft equipment much more economical.

There are three types of mechanical drafts.

Induced draft

Forced draft:

Balanced draft:

Induced draft:

This is obtained in one of the three ways, the first being the

stack effect of a heated chimney, in which the flue gas is less

dense than the ambient air surrounding the boiler. The more

dense column of ambient air forces combustion air into and

through the boiler. The second method is through use of a

steam jet. The steam jet oriented in the direction of flue gas

flow induces flue gases into the stack and allows for a greater

flue gas velocity increasing the overall draft in the furnace.

This method was common on steam-driven locomotive which

could not have tall chimneys. The third method is by simply

using induced draft fan which sucks flue gases out of the

furnace and up the stack. Almost all induced draft furnaces

have a negative pressure.

Forced draft:

Draft is obtained by forcing air into the furnace by means of a

fan (FD fan) and ductwork. Air is often passed through an air

heater, which, as name suggests, heats the air going into the

furnace in order to increase the overall efficiency of the

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boiler. Dampers are used to control the quantity of air

admitted to the furnace. Forced draft furnaces usually have a

positive pressure

Balanced draft:

Balanced draft is obtained through use of both induced and

forced draft. This is more common with larger boilers where

the flue gases have to travel a long distances through many

boiler passes. The induced draft fan works in conjunction

with the forced draft fan allowing furnace pressure.

Boilers in STPP in Stage#1 & 2 are highlighted as below.

MAKE TYPE

STAGE 1: BHEL

Controlled circulation balanced

draft furnace type tangential firing. STAGE 2

4.5 BOILER EQUIPMENT

Boiler equipment is divided into

Furnace

Water walls

Drum

Super heater

Re-heater

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Economizer

A) Super Heaters:

The super heater is a device which is used to remove the

last traces of moisture from the saturated steam leaving

from the boiler drum and also to increase temperature

above saturation level temperatures. For this, the heat

from flew gases is used. There are three stages of super

heaters besides the side walls and extended sidewalls.

The first stage consists of horizontal super heater (LTSH

or PSH) of convection mixed flow type with upper and

lower banks located above economizer assembly in the

rear pass. Convective heat transfer superheats the steam

as the flue gases from the furnace pass through this

section. The upper bank terminates into hanger tubes,

which are connected to outlet header of the first stage

super heater. The second stage super heater consists of

pendant platen which is of radiant parallel flow type. The

third stage super heater is Platent (FSH) spaced is of

convection parallel flow type.

The outlet temperature and pressure of the steam coming

out from the super heater is 540° C and 157 kg/cm2

respectively.

B) Re-Heaters:

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The function of Re-heaters is to re-heat the partly

expanded steam from the HP Turbine to a temperature of

540°C. This is done so that the steam remains dry as far

as possible through the last stages of the turbine. The

input for the re heater is Cold Reheat line (CRH) from the

HP turbine output and the output of the re heater is Hot

Reheat Line (HRH) which goes to IP turbine input.

C) Economizer:

When the combustion gases leave the boiler after giving

most of their heat to the water tubes, super heater tubes

and re-heater tubes. But they still possess a lot of heat, if

not recovered, would go waste. Economizer is a device

which recovers the heat from the flue gases on their way

to chimney and raises the temperature of the feed water.

This increases the boiler efficiency by 10 to 12%.

4.6 BOILER AUXILIARIES

Boiler auxiliaries are divided into

Boiler Water circulating pump (BCW)

Coal firing

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coal piping & burners

Coal burners

Oil firing

Induced Draft fan (ID Fan)

Forced Draft fan (FD Fan)

Primary air fan (PA Fan)

Scanner air fan

Air pre-heaters

◦ Primary air pre-heaters (PAPH)

◦ Secondary air pre-heater (SAPH)

◦ Steam coil air pre-heater (SCAPH)

A) Coal Firing System:

Coal Firing System deals with the feeding of coal from the

bunkers. The coal firing system consists of the mills and

the Raw Coal Feeder. The mills pulverize the coal from

the bunkers.

MAKE TYPE Qty.

STAGE 1

bowl mill 9 mills/ unit

STAGE 2 10 mills/ unit

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B) Coal Burners:

The coal burner consists of Carbon Steel piping of 658.8

mm dia. The burners are tangential firing type. There are

a total of 36 burners per unit and the temperature of the

coal air mixture.

C) AIR PRE HEATER (APH)

The purpose of the air pre-heater is to recover the heat

from the boiler flue gas which increases the thermal

efficiency of the boiler by reducing the useful heat lost in

the flue gas. As a consequence, the flue gases are also

sent to the flue gas stack or chimney at a lower

temperature, allowing simplified design of the ducting

and the flue gas stack. It also allows control over the

temperature of gases leaving the stack (to meet emissions

regulations, for example).

Types

There are two types of air pre-heaters for use in steam

generators in thermal power stations:

One is a tubular type built into the boiler flue gas

ducting and the other is a regenerative air pre-

heater. These may be arranged so the gas flows

horizontally or vertically across the axis of rotation.

Another type of air pre-heater is the regenerator

used in iron or glass manufacture

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Regenerative air pre-heaters:

In this design the whole air pre-heater casing is

supported on the boiler supporting structure itself with

necessary expansion joints in the ducting.

The vertical rotor is supported on thrust bearings at the

lower end and has an oil bath lubrication, cooled by water

circulating in coils inside the oil bath. This arrangement is

for cooling the lower end of the shaft, as this end of the

vertical rotor is on the hot end of the ducting. The top

end of the rotor has a simple roller bearing to hold the

shaft in a vertical position.

The rotor is built up on the vertical shaft with radial

supports and cages for holding the baskets in position.

Radial and circumferential seal plates are also provided to

avoid leakages of gases or air between the sectors or

between the duct and the casing while in rotation.

For on line cleaning of the deposits from the baskets

steam jets are provided such that the blown out dust and

ash are collected at the bottom ash hopper of the air pre-

heater. This dust hopper is connected for emptying along

with the main dust hoppers or the dust collectors.

The rotor is turned by an air driven motor and gearing

and is required to be started before starting the boiler

and also to be kept in rotation for some time after the

booker is stopped, to avoid uneven expansion and

contraction resulting in wrapping or cracking of the rotor.

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The station air is generally totally dry (dry air is required

for instrumentation), so the air used to drive the rotor is

injected with oil to lubricate the air motor.

Safety protected inspection windows are provided for

viewing the pre-heaters internal operation under all

operating conditions.

The baskets are in the sector housings provided on the

rotor and are renewable. The life of the baskets depends

on the ash abrasiveness and corrosiveness of the boiler

outlet gases.

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CHAPTER 6

TURBINE & AUXILIARIES

6.1 TURBINE

A steam turbine is a mechanical device that extracts thermal

energy from pressurized steam, and converts it into useful

mechanical work.

Principle of operation

An ideal steam turbine is considered to be an isentropic

process or constant entropy process, in which the entropy of

the steam entering the turbine is equal to the entropy of the

steam leaving the turbine. No steam turbine is truly

“Isentropic”, however, with typical isentropic efficiencies

ranging from 20%-90% based on the application of the

turbine. The interior of the turbine is comprised of several

sets of blades or buckets as they are more commonly referred

to. One set of stationary blades is connected to the casing

and one set of rotating blades is connected to the shaft. The

sets intermesh with certain minimum clearances, with the

size and configuration of sets varying to efficiently exploit the

expansion of steam at each stage.

There are two types of steam prime movers viz., steam

engines and steam turbines. Steam turbines are generally

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classified into two types according to the action of steam on

moving blades viz.

Impulse turbines

Reactions turbines

In STPP, Turbine types in Stage#1 & 2 are highlighted as given

below.

MAK

E

DESIGN TYPE

STAGE 1

BHEL

KWU,

WEST

GERMANY

3 CYLINDER REHEAT

CONDENSED TURBINE STAGE 2

6.2 TYPES OF TURBINE

Turbine types include condensing, non-condensing, re-heat,

extraction and induction.

Non-condensing or backpressure turbines are mostly

widely used for process steam applications. The

exhaust pressure is controlled by a regulating valve to

suit the needs of the process steam pressure. These

are commonly found at refineries, district heating

units, pulp and paper plants and desalination facilities

where large amounts of low pressure process steam

are available.

Condensing turbines are most commonly found in

electrical power plants. These turbines exhaust steam

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un a partially condensed state, typically of a quality

near 90%, at a pressure well below atmospheric to a

condenser.

Reheat turbines are also used almost exclusively in

electrical power plants. In a reheat turbine, steam flow

exits from a high pressure section of the turbine and is

returned to the boiler where additional superheat is

added. The steam then goes back into an intermediate

pressure section of the turbine and continues

expansion.

Extracting type turbines are common in all

applications. In an extracting type turbine, steam is

released from various stages of the turbine and used

for industrial process needs or sent to boiler feed water

heaters to improve overall cycle efficiency. Extraction

flows may be controlled with a valve or left

uncontrolled. Induction turbines introduce low

pressure steam at an intermediate stage to produce

additional power.

Casing or Shaft arrangements

These arrangements include single casing, Tandem

compound and cross compound turbines. Single casing

units are the most basic style where a single casing and

shaft are coupled to a generator. Tandem compound are

used where two or more casings are directly coupled

together to drive a single generator. A Cross compound

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turbine arrangement features two or more shafts not in

line driving two or more generators that often operate at

different speeds. A Cross compound turbine is typically

used for many large applications.

6.3 STAGES OF TURBINE

Turbine is divided into 3 stages

HPT-High pressure turbine

IPT-Intermediate pressure turbine

LPT-Low pressure turbine

First stage consists of IMPULSE type: for high speeds

The rest of the three stages consist of REACTION type: for low

speeds.

A) High Pressure (HP) Turbine:

The steam is initially passed through the HP Turbine.

Here, the steam loses some of its pressure and heat as it

comes in contact with the blades of the turbine. The

superheated steams from the super heaters enter the HP

turbine where it is freely expanded radially in all

directions and axially from a fixed point. From the HP

turbine outlet the expanded steam is again sent for

reheating. One extraction is taken from HP turbine, where

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the steam from CRH is sent to the HP heaters 6A & 6B to

heat the feed water. The HP turbine casing is designed as

a barrel type casing without axial joint.

B) Intermediate Pressure (IP) Turbine:

The IP turbine is split horizontally and is of double shell

and double flow construction. Steam from the reheat lines

enters the inner casing from the top and bottom through

two inlet nozzles flanged into the mid section of the outer

casing. The centre flow prevents the steam inlet

temperature from affecting the support brackets and

bearing sections. Two extractions take place in IP turbine,

where the steam from one extraction is sent to the

Deaerator and the boiler feed pump.

C) Low Pressure (LP) Turbine:

The LP turbine is of double flow and triple shell welded

casing. The steam from the IP turbine enters the LP

turbine and flows into the inner casing from both sides

through steam inlet nozzles before the LP blading. Three

extractions take place, where the extracted steam is sent

to the Three LP heaters.

There are different control valves at each stage like the main

stop and control valves such as re-heat stop and control

valve, swing check valve etc. All the three turbines are

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mounted on the same shaft and mechanically coupled to the

generator.

6.4 TURBINE EQUIPMENT

Turbine equipment is divided into following.

Main turbine

Turbine lube oil system

Turbine control system (Control fluid system)

Condenser

LP Heater

Dearator & FST

HP Heater

A) CONDENSER

In thermal power plants, the primary purpose of a surface

condenser is to condense the exhaust steam from a

steam turbine to obtain maximum efficiency and also to

convert the turbine exhaust steam into pure water

(referred to as steam condensate) so that it may be

reused in the steam generator or boiler as boiler feed

water.

The steam turbine itself is a device to convert the heat in

steam to mechanical power. The difference between the

heat of steam per unit weight at the inlet to the turbine

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and the heat of steam per unit weight at the outlet to the

turbine represents the heat which is converted to

mechanical power. Therefore, the more the conversion of

heat per pound or kilogram of steam to mechanical power

in the turbine, the better is its efficiency. By condensing

the exhaust steam of a turbine at a pressure below

atmospheric pressure, the steam pressure drop between

the inlet and exhaust of the turbine is increased, which

increases the amount of heat available for conversion to

mechanical power. Most of the heat liberated due to

condensation f the exhaust steam is carried away by the

cooling medium (water or air) used by the surface

condenser.

Condensate Extraction Pump:

These pumps are run by constant speed motors through

a rigid coupling, vertical barrel, double barrel, double

section, multi stage, diffuser type. Condensate from the

hot well is pumped to deaerator by these pumps. These

pumps require Net Positive Suction Head (NPSH), as there

are negative levels.

Condensate polishing unit (CPU):

CPU is used for polishing the condensate to help in

regaining its properties if the properties are deteriorated.

Gland Steam Condenser:

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GSC is used for the condensation of the Leak off steam

from the turbine glands.GSC uses the leakage steam as

input which is coming from the sealing system provided

for the turbines which is used to avoid the leakage of

steam.

B) Low Pressure heater:

Before entering the Deaerator, the condensate gains some

temperature in Low pressure heaters (LPH). These are

special type of shell and tube heat exchangers, where the

condensate is heated by recovering the heat from a

turbine extracted steam. There are three heaters where

the drain from the first LP heater enters the second and

subsequent third one.

Corrosion

On the cooling water side of the condenser:

The tubes, the tube sheets and the water boxes may be

made up of materials having different compositions and

are always in contact with circulating water. This water,

depending on its chemical composition, will act as an

electrolyte between the metallic composition of the tubes

and water boxes. This will give rise to electrolytic

corrosion which will start from more anodic materials

first.

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‘Sea water based condensers’, in particular when sea

water has added chemical pollutants, has the worst

corrosion characteristics. River water with pollutants is

also undesirable for condenser cooling water.

The corrosive effect of sea or river water has to be

tolerated and remedial methods have to be adopted.

On the steam (shell) side of the condenser:

The concentration of undissolved gases is high over air

zone tubes. Therefore these tubes are exposed to higher

corrosion rates. Some tomes these tubes are affected by

stress corrosion cracking, if originally stress is not fully

relieved during manufacture. To overcome these effects

of corrosion some manufactures provide higher corrosive

resistant tubes in this area.

Effects of corrosion

As the tube ends get corroded there is the possibility of

cooling water leakage to the steam side contaminating

the condensed steam or condensate, which is harmful to

steam generators.

The other parts of water boxes may also get affected in

the long run requiring repairs or replacements involving

long duration shut-downs.

Protection from corrosion

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Cathodic protection is typically employed to overcome

this problem. Sacrificial anodes of Zinc (being cheapest)

plates are mounted at suitable places inside the water

boxes. These Zinc plates will get corroded first being in

the lowest range of anodes. Hence these Zinc anodes

require periodic inspection and replacements. This

involves comparatively less down time. The water boxes

made of steel plates are also protected inside by epoxy

paint.

C) DEAERATOR

A Deaerator is a device for air removal and is used to

remove dissolved gases (an alternate would be the use of

water treatment chemicals) from boiler feed water to

make it non-corrosive. A deaerator typically includes a

vertical domed deaeration section mounted on top of a

horizontal cylindrical vessel which serves as the deaerated

boiler feed water tank.

Necessity for Deaeration

A steam generating boiler requires that the circulating

steam, condensate and feed water should be devoid of

dissolved gases, particularly corrosive ones and dissolved

or suspended solids. The gases will give rise to corrosion

of the metal. The solids will deposit on the heating

surfaces giving rise to localized heating and tube ruptures

due to overheating. Under some conditions it may give

rise to stress corrosion cracking.

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Mounting arrangement

The feed tank is mounted horizontally at a sufficient

height above the boiler to provide the Net Positive Suction

Head (NPSH) to the boiler feed pump under all conditions

of the system operation.

Controls and monitoring

Normally, all the control and monitoring equipment for

startups, normal operation and alarms for out of

parameter operations are provided at the operator’s

console.

Deaerator level and pressure must be controlled by

adjusting control valves. The level is maintained by

regulating condensate flow and make-up water. Pressure

is maintained by regulating steam flow.

If operated properly, most deaerator vendors will

guarantee that oxygen in the deaerated water will not

exceed 7 ppb by weight (0.005cm^3/L)

6.5 TURBINE AUXILIARIES

Turbine auxiliaries are divided into the following

Boiler Feed Pump (BFP)

Booster Pump

Vacuum raising system

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TG equipment cooling water system

Auxiliary Cooling Water System (ARCW)

Condenser On load Tube cleaning system (COLTCS)

A) BOILER FEED WATER PUMP

A Boiler feed water pump is a specific type of pump used

to pump feed water into a steam boiler. The water may be

freshly supplied or returning condensate produced as a

result of the condensation of the steam produced by the

boiler. These pumps are normally high pressure units that

use suction from a condensate return system and can be

of the centrifugal pump type or positive displacement

type.

Feed water pumps range in size up to many horsepower

and the electric motor is usually separated from the pump

body by some form of mechanical coupling. Large

industrial condensate pumps may also serve as the feed

water pump. In either case, to force the water into the

boiler, the pump must generate sufficient pressure to

overcome the steam pressure developed by the boiler.

This is usually accomplished through the use of a

centrifugal pump.

Feed water pumps usually run intermittently and are

controlled by a float switch or other similar level-sensing

device energizing the pump when it detects a lowered

liquid level in the boiler. The pump then runs until the

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level in the boiler is substantially increased. Some pumps

contain a two-stage switch. As liquid lowers to the trigger

point of the first stage, the pump is activated. If the liquid

continues to drop (perhaps because the pump has failed,

its supply has been cut off or exhausted or its discharge

is blocked), the second stage will be triggered. This stage

may switch off the boiler equipment (preventing the

boiler from running dry and overheating), trigger an

alarm, or both.

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CHAPTER 7

GENERATOR

7.1 TECHNICAL SPECIFICATION

500 MW THDF 115/59 TG:

UNIT 1 TYPE: TG-HW-0500-2

SL.NO: 10526-P-129-01

UNIT 2 TYPE: TG-HW-0500-2

SL.NO: 10527-P-129-01

GENERATOR 500 MW, 588 MVA, 16.2 KA,

21 KV, 0.85 PF(lag),

FREQUENCY 50Hz

H2 PRESSURE 3.5 BAR.

EXCITATION 340 V, 4040 A.

CRITICAL SPEEDS: 864, 1806, 2388 RPM

SUBTRANSIENT REACTANCE Xd ‘’ 7.2 %

TRANSIENT REACTANCE Xd ’ 24.1 %

SYNCHRONOUS REACTANCE Xd 231 %

SHORT CIRCUIT RATIO 0.52

ZERO PF LAG CAPABILITY 433 MVA

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ZERO PF LEAD CAPABILITY 250 MVA

TOTAL LOSSES IN GENERATOR TOTAL TO 6920 KW,

BREAK UP AS FOLLOWS:

IRON LOSSES 600 KW.

SHORT CIRCUIT LOSSES 2800 KW.

EXCITATION LOSSES 1390 KW.

WINDAGE LOSSES 1680 KW

BEARING & SEALS LOSSES 450 KW

EFFICIENCIES

AT FULL LOAD & AT 75% FULL LOAD: 98.63%

AT 50% FULL LOAD 98.44%.

AT 25% FULL LOAD 97.50%

7.2 CONSTRUCTION

A) STATOR

The generator has built in end shields bearings. Core

suspension system using flat - plate springs, keeps the

stator body vibrations low and within acceptable limits.

21 springs are provided at the machine bottom and at

both its sides. Mild steel pressure plates and axial studs

keep core tight. Core ends are shielded from end leakage

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magnetic fluxes by H2 cooled magnetic steel flux shields.

Stator core is insulated from the frame except for one

earthing core bar. Stator core is cooled by H2 flow in

radial ducts. All four cooler sections are vertically

mounted. A control valve on cold water flow side, based

on load, automatically adjusts cold water flow. This

ensures nearly uniform temperatures inside generator

irrespective of loads. Ring type double flow H2 shaft

seals, with separate air and Hydrogen side oil flows, are

reliable and give low H2 gas consumption. Distortion free

seal rings carriers are provided.

B) ROTOR

Rotor shaft forging is single piece vacuum cast and then

forged from low alloy steel to achieve high electro-

magnetic as well as mechanical properties. Both poles are

provided with cross pole slots for inertia equalization.

Rotor is fitted with 18Mn -18Cr non-magnetic steel

retaining rings for winding retention. The rings are

shrunk fitted and locked axially by snap rings. Seating

surfaces of rings and the shaft are silver coated. Class ‘F’

layers electrically insulate the rings from copper

underneath. Axial flow multi-stage fans/compressors

fitted on shaft at turbine end. Copper forged field leads

carry DC-rotor current from exciter to the rotor coils.

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C) STATOR WINDING

RESIATNACE IN OHMS AT 20°C U-X 0.001440 Ω, V-Y

0.001440 Ω, W-Z 0.001440 Ω

3 phase fractional pitch, 2 layer winding. Each slot has

Winding consists of polyester-mica splitting-epoxy resin,

having high electrical, mechanical and thermal / aging

properties. All bars are coated with semi-conducting

varnish in their slot portions. End corona protection is

provided in overhang portions. Slot bottom equalizing

strips are provided between the bars and stator slots. Top

and side ripple springs are provided.

D) ROTOR WINDING

RESIATNACE IN OHMS AT 20°C F1-F2:0.06700 Ω.

The rotor winding consists of silver bearing copper

conductors for higher creep resistance and mechanical

strength. Trapezoidal slots are milled in the shaft for very

high shaft utilization and conductors are also trapezoidal.

Insulation between turns are made of class F laminated

glass - epoxy. Cu-Co-Be-Zr copper alloy slot wedges are

used in rotor slots. They also act as damper bars for

shaft circulating currents. Slot end wedges are Silver-

plated to improve conductivity of eddy currents that flow

on rotor surface in case of unbalanced or asynchronous

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machine operation. Wedges are snug fitted, permitting

thermal expansions. Rotor field leads get connected to

brushless exciter leads by silver plated multi contacts.

Current from field leads is transferred to rotor coils by

means of thread-less special current carrying bolts. Bolts

are sealed adequately, by rubber rings against escape of

Hydrogen gas via field leads.

E) TEMPERATURE RISES

IEC-34 permits maximum rotor winding Temp. Rise 62°C .

Actual expected rise is 31°C.

IEC-34 permits maximum stator winding Temp. Rise

37°C. Actual expected rise is 27°C.

IEC-34 permits maximum stator core Temp. Rise 77°C

based on RTDs. but actual as measured at hottest point in

type tests was only 41°C at teeth.

Magnetic flux density in both stator & rotor 2 - 2.5

Tesla.

Heat load for all H2 coolers 4424 KW.

Without one cooler full load permitted.67%

Machine is unloaded if H2 pressure < 3.1 bar.

Continuous unbalanced load of 8 % and on short time

basis, I2 ² t value of 10 is permitted.

Over-current is allowed for very brief spells as per O & M

manual. Thus for example, restricted operation is

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allowed for 90 sec at 120% rated current, or for 25 sec at

160 % rated current.

No operation is permitted without primary water flow in

winding.

Voltage-frequency combination variations in operation

permitted as per O&M manual.

F) WINDING TEMPERATURE MONITORING

Outlet water header has RTDs embedded in each outlet

hot water header nipple. These are thermally insulated

and connected to continuous monitoring system with

alarm provisions. Hot flow temperature monitoring

method gives accurate data vis a vis conventional slot

RTD method. Also flow monitoring of circuits is possible.

G) VENTILATION & COOLING

GENERATOR (GAS)VOLUME 80 m3.

CO2 FILLING QUANTITY 160M3 AT S.T.P

H2 FILLING QUANITY 480m3 AT S.T.P

Gas flow path 1 enters rotor on Turbine end and cools

rotor overhang and slots.

Gas flow path 2 cools stator core.

Gas flow 3 enters rotor on exciter end & cools rotor

overhang and rotor slots, as well as stator core end parts

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at both the ends.

Hot gas from all paths returns through air gap to

compressor and then to the gas coolers.

Hydrogen enters rotor ends and then into axial ducts

provided in rotor copper strip conductors in rotor slots.

Hot gas comes out from them radially, at barrel center

through number of radial holes provided in conductors

and in slot wedges. Gas also enters into winding

overhangs at both the barrel ends. Hot gas is then

collected in special chambers and then discharged into

the air-gap.

H) COOLANT TEMPERATURE CONTROL

Load changes lead to stresses. These are due to unequal

thermal expansion coefficients and unequal expansions

of winding copper, insulation and core iron. CW flow to

Hydrogen gas coolers is varied with load to achieve nearly

uniform machine temperatures. Secondary water flow

through primary water coolers is varied with load, also

towards maintaining uniform temperatures. With load,

cold coolant references are automatically reduced, such

that mean value of hot and cold remains nearly constant.

Cold gas temperature is changed with load by sensing

stator current; being a function of (Stator current)².

Parallel displacement of the cold gas curve is possible by

adjusting the set value of cold gas at no load. It is

theoretically possible either to keep mean of cold and hot

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gas temperatures constant, or maintain hot gas

temperature constant.

I) SEAL OIL SYSTEM (DOUBLE FLOW SEAL)

There are two separate seal oil systems in Generators.

One system runs saturated with Hydrogen and is at higher

pressure to prevent leaking of Hydrogen gas along the

shaft. Air side seal oil system caters to outer chamber in

shaft seals here outgoing oil gets mixed with bearing oil.

Air-side circuit has three oil pumps. Only one pump runs.

Air side oil is air - saturated. H2 side oil runs saturated

with H2 and have no air in it. Thus entry of air to H2

chamber is kept at minimum, so H2 purity is maintained.

H2 side has one pump only. If it fails, airside system

supplies oil to H2 side also. H2 purity goes down. If

prolonged, purity is improved by scavenging. Air-side

seal oil pressure is slightly higher than H2 side. Very

small quantity flows from air-side to H2 side.

Float valve in seal-oil tank returns excess oil to seal-oil

storage tank. Differential pressure regulating valve

controls sealing oil pressure above H2 pressure for AC

pumps. Another Differential pressure regulating valve

controls for 3rd standby, i.e. DC pump. For H2 side seal-

oil pressure, another differential press regulating valve is

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used, that takes signal from air-side seal oil pressure.

Constant differential pressure between air and H2 side oil

is controlled by separate pressure equalizing control

valves for each seal. Free movement of seal rings is

ensured by feeding ring relief press oil. It comes from air

side oil. Pressures for each seal are set separately at 8.5

mtr seal oil valve rack.

J) PRIMARY WATER SYSTEM

Primary water required for cooling the stator winding is

circulated in a closed system. In order to prevent

corrosion only copper stainless steels or similar corrosion

resistant material are used throughout the entire cooling

circuit.

K) BEARING AND SHAFT SEALS

Built in end shield bearings insulated on both TE and EE

from earth. Bearing bore is of elliptical shape i.e. having

greater clearances at sides than on top.

Clearance at maximum diameter of ellipse:

Horizontal clearance Sh (radial) = 0.88 - 0.94

Top clearance Sv (diametrical) = 0.52 - 0.63

Contact arc length of shaft with bearing liner babbbit B =

190 ± 10.

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Dia 'C' i.e. larger diameter of ellipse: 451.8 ± 0.04.

Shaft seals: Shaft Dia: 450 - 0.04.

Radial clearances between shaft and seal rings are 0.31 -

0.35.

Oil catcher radial clearances are = 0.17 - 0.30

L) HYDROGEN GAS COOLERS

4 SECTIONS EACH RATED FOR 25%.

GAS FLOW 33 CUM/SEC.

HEAT DISSIPATION PER COOLER 5050 KW

HOT / COLD GAS TEMP. 75.5 / 43.7 °C

GAS PRESSURE DROP 620 Pa

COOLING WATER FLOW 114 dm3/S CW

INLET / OUTLET TEMPS. 38.7/45.8 °C

TUBES OF CuZn28Sn, FINS OF COPPER.

M) PRIMARY WATER TREATMENT SYSTEM

It is important that PW pumps have effective gland sealing

preventing air-suction. If air is sucked in, Oxygen ingress

increases and conductivity values shall go up. Also copper

corrosion rate goes up. Mixed bed ion exchanger is

provided to keep water conductivity low. 5 Micron filter is

provided in the system to arrest resin particles.

Integrating flow meter and conductivity meter are also

provided. Make up water quantity upstream and total

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make up volume is monitored. DM plant to give clean

water for the winding make up etc, free from iron oxides

to prevent deposits in winding. Whenever there is need to

test PW circuit, it should be done with 6 bar N2 pressure

in PW tank and the PW system full of water.

N) STATOR WINDING HOLLOW COPPER CORROSION

Corrosion of hollow conductors is harmful since it leads

to decrease in water flow. Oxygen corrodes copper - CuO

and Cu2O are formed. Corrosion is uniform along length

but deposits are more at conductor outlets. Each hollow

conductor is air checked for clear flow worthiness. Air /

water or mild acid flushing is followed by water flushing.

Flow is checked in each hollow conductor.

Very low or very high oxygen content in winding water

both give low corrosion levels of hollow copper. For 500

MW low oxygen levels 10 - 20 ppb are recommended.

NaOH added water with pH value of 8.5 - 9 gives

optimum results. Water conductivity at these pH values

tends to increase. Conductivity to be less than 10 micro

mho/cm, say : 0.5 micro mho/cm. CO2, Chlorides and

other anions to be minimum. CO2 content to be nil.

Conductivity after strongly acidic cation exchanger < 0.2

Micro mho/cm. Ammonia to be minimum. Test with

Nessler’s solution shall not cause change in color. Copper

and Iron in dissolved or undissolved form to be less than

20ppb. Ph value of 8.5 to 9 gives optimum results.

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Dilute 1 - 2% NaOH is added to obtain high pH levels.

Integrated alkalyzer unit is used. But conductivity shall

slightly increase.

O) Generator& Auxiliaries

Each alternator is coupled to a steam turbine and converts

mechanical energy of the turbine into electrical energy.

The alternator may be hydrogen or air or water cooled

where stator is water cooled and rotor is gas cooled. The

necessary excitation is provided by means of main and

pilot exciters directly coupled to the alternator shaft.

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CHAPTER 8

TRANSFORMERS

8.1 INTRODUCTION

A transformer is an energy transfer device. It has an input

side (primary) and an output side (secondary). Electrical

energy applied to the primary is converted to a magnetic field

which in turn, induces a current in the secondary which

carries energy to the load connected to the secondary. The

energy applied to the primary must be in the form of a

changing voltage which creates a constantly changing current

in the primary, since only a changing magnetic field will

produce a current in the secondary.

A transformer consists of at least two sets of windings wound

on a single magnetic core. There are two main purposes for

using transformers. The first is to convert the energy on the

primary side to a different voltage level on the secondary

side. This is accomplished by using differing turns counts on

primary and secondary windings. The voltage ratio is the

same as the turns ratio. The second purpose is to isolate the

energy source from the destination, either for personal

safety, or to allow a voltage offset between the source and

load.

Transformers are generally divided into two main types.

Power transformers are used to convert voltages and provide

operating power for electrical devices, while signal

transformers are used to transfer some type of useful

information from one form or location to another.

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Following are the Main Power transformers used in the

Simhadri power plant.

Generator Transformer

Unit Transformer

Standby Transformer

8.2 GENERATOR TRANSFORMER (GT)

There are two Generator Transformers one to each of the

Generator. This Generator Transformer is connected between

generator and switch yard which steps up 21 KV to 400 KV. It

is connected in star-delta connection with the secondary star

neutral is solidly grounded.

Rating of Generator Transformer are as follows:

Phase: 3 x 1 phase

MVA rating: 120/160/200 MVA

KV rating: 420/sqrt (3)/21 KV

Current rating: 11000 Amps

Cooling: ONAN/ONAF/OFAF

Z = 13.5%, +/- 5% Tolerance at principle tap

Z min = 12% at maximum tap

Z max = 15% at minimum tap

Off circuit tap changer: +5 to -5% in steps of 2.5%

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8.3 UNIT TRANSFORMERS (UT)

It is a transformer which steps down the voltage from 21 KV

to 11 KV which is supplied to the other auxiliaries. There are

four Unit Transformers, two for each Generator.

These two Unit Transformers are connected to Generator to

supply auxiliary power to plant. Each Transformer supplies to

one 11KV switchgear. Four such switchgears are provided in

the station. Vacuum Circuit Breakers are used in the 11KV

Switchgear for feeding power supply to motor and

transformers.

Each Unit Transformer is connected in delta-star connection

with star side neutral resistively grounded.

If fault occurs in one Unit Transformer then loads connected

to that transformer will change over to 400KV/11KV Standby

Transformer .If there is a fault in one unit the loads

connected to that unit are fed by the 400KV/11KV Standby

Transformer.

Rating of UT are as follows:

Phase: 3-phase

MVA rating: 40/50 MVA

KV rating: 21/11.5 KV

Current rating:

Cooling: ONAN/ONAF

Z = 13% at principal tap

Z min = 10.5% at minimum tap

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Z max = 14% at maximum tap

On load tap changer: +7.5% to -12.5% in steps of 1.25% on

HV side

8.4 STANDBY TRANSFORMER (ST)

It is a transformer which steps down the voltage from 400 KV

to 11 KV supply. There is only one Standby Transformer in

the total plant. This transformer supplies power to the unit

switch gears whenever any one or both the Unit

Transformers fail. Standby Transformer is connected in star-

star fashion with both primary and secondary neutrals being

solidly grounded.

Rating of ST are as follows:

Phase:

MVA rating: 40/50 MVA

KV rating: 400/11.5 KV

Current rating:

Cooling: ONAN/ONAF

Z = 12.5% at principle tap

Z min = 9.5% at maximum tap

Z max = 16.5% at minimum tap

On load tap changer: +/- 10% in steps of 1.25% on HV side

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8.5 DG SETS

DG set is provided for the safe shutdown of the unit, in the

event of a grid failure. To safely shut down the unit, the

turbine has to be brought to rest gradually, and there are

several units like the generator seal oil system, emergency

lighting, and Data Acquisition Units, which have to be

constantly powered.

If the grid is active, then these loads are powered from the

grid by use of the Station Transformers. If the grid has failed,

the DG sets are used to run the loads till the unit is

completely turned off.

MAKE Rating

STAGE

1

Poweri

ca

415V, 3x1500

KVA

STAGE

2

Jackso

n

415V, 3x1250

KVA

There is 1 no. of DG per unit and 1 no. of standby per stage.

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CHAPTER 9

OFFSITE AREAS

9.1 WATER SYSTEM

The water system forms one of the vital systems of the Plant.

It constitutes the generation and circulation of de mineralized

(DM) water and cooling water. The water system mainly

consists of the following sections

A) Sea water pump house:

In NTPC Simhadri, Sea Water is used for cooling purposes.

A Sea Water Pump House is set up at 685 meters from

shore into sea. There are total of 2 pumps of 1 meter

diameter and ratings are 2500 litres/second and total

head of 43.3 meters and pump input is 1152.4 KW. The

pump motors are electrically mounted type. They have

the facility of electro chlorination to separate chlorine

from water through electrolysis.

B) CW system:

The CW pumps are used to circulate the sea water

through the plant from the Sea Water Reservoir. They are

a total of 5 pumps of concrete volute type. The pump

motors are squirrel cage.

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C) Cooling Towers:

The cooling towers are huge concrete structures used to

cool the hot sea water from the condenser and they use

natural draft. Sweetwater is used for the production of

steam in the boiler .In the heat exchanger in order to cool

this water, sea water is used as a heat exchange medium.

In the cooling tower to cool this hot water either natural

drought or forced drought cooling towers are used. In

Natural draft type design no pumps or fans are used to

circulate or cool the water. Where as in forced draft

cooling towers pumps and fans are used to circulate the

water. Here in NTPC Simhadri natural drought cooling

towers are used. In this type, scrubbers are arranged

through which hot sea water is forced to pass through.

While passing through these scrubbers, the water gets

cooled. As it is a closed loop the cooled water is again

sent back to the heat exchanger. There are two towers.

The height of each tower is 165 meters and hot water

temperature is 43.5 degrees and cool water temperature

is 32. 5 degrees.

E)Sweet Water Pump House:

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The Plant needs Sweet water for the Boiler. This

requirement is fulfilled by the Sweet Water Pump House.

The Pump House takes water from yelluru Canal.

D) Pre Treatment and DM Plant

The water used for generation of steam inside the boiler

should be free from any minerals or corroding materials

or else there is a high risk of chocking of tubes and this

may lead to damage of boiler. Hence, the water is being

de mineralized.

The impurities in the raw water input to the plant

generally consist of calcium and magnesium salts which

impart hardness to the water. Hardness in the make-up

water in the boiler will form deposits on the tube water

surface which leads overheating and failure of tubes.

Thus the salts have to be removed from the water and

that is done by water de-materialization treatment (DM).

A DM plant generally consists of cation, anion and mixed

bed exchangers. The final water from this process

consists essentially of hydrogen and hydroxide ions which

is the chemical combination of pure water. The DM water

being very pure becomes highly corrosive once it absorbs

oxygen.

The capacity of DM plant is decided by the type and

quantity of salts and raw water input. However some

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storage is essential as the DM plant may be down for

maintenance. For this purpose a storage tank is installed

from which DM water is continuously withdrawn for boiler

make-up. It is made up of material such as PVC. The

piping and valves are generally stainless steel. DM water

make-up is generally added at the steam space of the

surface condenser. This arrangement not only sprays

water but also DM water gets de-aerated, with the

dissolved gases being removed by the ejector of the

condenser itself.

9.2 COAL HANDLING PLANT:

Coal is stored in the coal storage plant. From the coal storage

plant, coal is delivered to the coal handling plant where it is

pulverized (i.e., crushed into small pieces) Pulverization is

done in order to increase its surface exposure, thus

promoting rapid combustion without using large quantity of

excess air.

9.3 ASH HANDLING PLANT

Ash produced may be to the tune of 10% to 15% of coal fired

.Ash slurry is made by wetting the fly ash and is pumped and

dumped in ash dykes which are located 10-15fkms away

from the power plant. The produced ash is pumped to sumps

in the form of wet ash and the fly ash is sent to the cement

companies.

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9.4 FUEL OIL PUMP HOUSE

For burning the coal at starting the oil is used and for safety

measures the fuel oil (HFO &LDO) tanks are placed at very far

away from the main plant. For pumping the fuel from there

fuel oil pump house is constructed where it employs drives

for pumping the fuel.

9.5 H2 PLANT

The Hydrogen plant of Simhadri has a capacity to generate

7.5 cubic meters of hydrogen per hour. The hydrogen is

produced by means of water electrolysis in the Electrolyser.

The electrolyser is filled with a solution of KOH in DM water

at a concentration of 25%. The electrolysis is achieved by the

passing of direct current from a rectifier through the cells

block. The oxygen generated in this electrolysis is vented out

to the atmosphere through a pressure balancing seal.There

are three important sections for this plant, namely the

Electrolyser section, the compressor section and the filling

station.

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CHAPTER 10

SWITCHYARD

10.1 INTRODUCTION

Switchyard as a main connecting link between the generating

plant and transmission systems has a large influence on the

security of supply. As the switchyard handles large amount of

power, it is considered essential that it remains secure and

serviceable to supply the outgoing transmission system even

under conditions of major equipment or busbar failure. The

choice of a bus switching scheme is governed by various

factors which ultimately aim at achieving the objective of the

security.

In all these regions there are switchgears. The switchgear in

generating stations can be classified as

Main switchgear

Auxiliary switchgear.

Main switchgear comprises of circuit-breakers, isolators, bus

bars, current transformers, potential transformers, etc. in the

main circuit of generator associated transformers of

transmission lines. It is generally of EHV and outdoor type.

Auxiliary switchgear is generally indoor type and controls the

various auxiliaries of the generator, turbine, boiler and the

station auxiliary.

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The functions of switch yard are as follows:

Main link between generating plant and Transmission

system, which has a large influence on the security of the

supply.

Step-up and/or Step-down the voltage levels depending

upon the Network Node.

Switching ON/OFF Reactive Power Control devices, which

has effect on Quality of power.

10.2 M

AIN EQUIPMENTS USED IN SWITCH YARD:

A) Bus bars:

These are conducting bars to which a number of local

feeders or numbers of circuits are attached. They are of

hollow aluminum circular conductors. Bus bars are merely

convenient means of connecting switches and other

equipment into various arrangements. The usual

arrangements of connections in most of the substations

permits working on almost any piece of equipment

without interruption to incoming of outgoing feeders

B) Solid Core Post Insulator

They prevent any leakage current from conductor to

earth.

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C) Capacitor Voltage Transformer (CVT):

To step-down the high magnitude of voltage to a safe

value to incorporate Measuring and Protection logics .The

primary voltage is applied to a series of capacitors group.

The voltage across one of the capacitor is taken to

auxiliary PT. The secondary of the aux PT is taken for

measurement and protection.

D) CURRENT TRANSFORMERS (CT):

To step-down the high magnitude of current to a safe

value to incorporate Measuring and Protection logics .

Current transformers are used for the instrumentation,

protection or metering of power systems.

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Current transformers are divided into two groups they

are:

Protective current transformers: They are used in

association with relays, trip coils, pilot wires etc.

Measuring current transformers: They are used in

conjunction with ammeter, wattmeter etc.

Combined together PT’S and CT’S are called as instrument

transformers.

E) SURGE ARRESTERS (SA):

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Safe guards the equipment by discharging the high

currents due to Lightning and to discharge the high

voltage surges in the power system due to lightning to

the ground.

F) ISOLATORS AND EARTH SWITCHES:

Isolators are disconnecting switches, which operate under

no-load conditions and it is not designed to make a

circuit under load or short-circuit condition.

Earth switch is connected between the line conductor and

earth and it is earthed. Normally it is open and it is closed

to discharge the voltage trapped on the isolated or

disconnected line. When the line is disconnected from the

supply end there is some voltage on the line to which the

capacitance between the line and earth is charged. This

voltage is significant in hv systems. Before

commencement of maintenance work it is necessary that

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these voltages are discharged to earth by closing the ear

thing switch. Normally, the earthing switches are

mounted on the frame of the isolator.

Isolator cannot be opened unless the circuit breaker is

opened and circuit breaker cannot be closed unless the

isolator is closed and these two are interlocked to serve

the above functions.

G) CIRCUIT BREAKERS:

Makes or automatically breaks the electrical circuits under

loaded condition.

On the basis of type of current they may be classified as

Ac circuit breakers

Dc circuit breakers

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However, most general way of classification of circuit

breakers is on the basis of medium of arc extinction such

as

Air-break circuit breakers

Oil circuit breakers

Minimum oil circuit breakers

Air-blast circuit breaker

Sulphur Hexafluoride circuit breaker

Vacuum circuit breaker

But in NTPC all the breakers used in switch yard are SF6

Breakers because of following advantages.

Minimum current chopping tendency at low

pressure and velocity

High dielectric strength

Outstanding arc quenching properties (small arcing

times)

Not affected due to atmospheric conditions.

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H) Overhead earth wire:

Protects the over head transmission line from lightning

strokes.

I) Reactive power control devices:

Controls the reactive power imbalance in the grid by

switching ON/OFF the Shunt Reactors, Shunt Capacitors

etc

J) Current Limiting Reactors:

Limits the Short circuit currents in case of faulty

conditions.

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K) Batteries:

In electric power stations and large capacity sub stations,

the operating and automatic control circuits, the

protective relay systems, as well as emergency lighting

circuits, are supplied by station batteries. The latter

constitute independent sources of operative dc power and

guarantee operation of the above mentioned circuits

irrespective of any fault which occurred in the station or

sub- station, even in the event of complete disappearance

of the supply in the installation.

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CONCLUSION

The current generation of the electric power is unfortunately

unable to suit the emerging demands of the country. If “India -

2020 “vision is to be reached for the country becoming a major

superpower it is the power-sector which needs tremendous

growth.

Thermal power plants are catering to a great extent in the regard.

In the process, the NTPC is successful in powering India’s growth

by providing a world class integrated power major with innovative

and eco-friendly technologies, thus increasing global presence.

But still there is scope for improvement by installing thermal

power plants of larger MW-like 660 MW & 800 MW units. Also

there is need to exploit the vast hydro-power potential of about

1,50,000 MW available in the country and last but not the least

there is the need of the mighty “Nuclear power” which all

together will make India a real superpower

Thus increase in power will automatically aid to economic growth

which will give India the position in the world which it truly

deserves.

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NTPC is also successfully in adopting new technologies like VFD

system and that to first time in Simhadri which has been studied

here and it had been observed that it got less power

consumption when operating at different speeds and this is the

advantage when compared to its competitors like inlet guide vane

control, outlet damper control and flow control.

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Power plant overview_2

Engineering

Transcript of Power plant overview_2