THERMAL POWER PLANT PROJECT REPORT

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A MINI PROJECT REPORT ON

THERMAL POWER PLANT FAMILIARISATION

Submitted in partial fulfillment for the award of the degree

Of

BACHELOR OF TECHNOLOGY

IN

MECHANICAL ENGINEERING Submitted By

B.MOUNIKA 13J41A0311

Under the Supervision of

RAHUL

ASSISTANT ENGINEER

MALLA REDDY ENGINEERING COLLEGE

(Autonomous)

Maisammaguda, Dhulapally(Post via Kompally), Secunderabad. 500 100

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MALLA REDDY ENGINEERING COLLEGE (Autonomous)

Maisammaguda, Dhulapally(Post via Kompally), Secunderabad- 500018.

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Department of Mechanical Engineering

CERTIFICATE

This is to certify that the Mini Project work entitled “ Thermal Power Plant

Familiarisation’’ is submitted in partial fulfillment of the requirement for the award of degree of

Bachelor of Technology in Mechanical Engineering discipline of JNTUH, Hyderabad for the

academic year (2016-17) is a record bonafide work carried by out by

B.MOUNIKA 13J41A0311

Co-ordinator HOD P.SNEHITH RAM A.RAVEENDRA

External Exam

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CONTENTS

Title Page NO

CHAPTER 1 INTRODUCTION……………………………7-11

1.1 GENERAL……………………………………………….. ..7

1.2 SPECIAL DESIGN FEATURES………………………. 8

1.3 ALTERNATIVE COOLING WATER SYSTEM…….. 9

1.4 ENVIROMENT…………………………………………... 9

1.5 PERFORMANCE…………………………………………10

CHAPTER 2 GENERAL LAYOUT AND BASIC IDEA . ..12-14

2.1 FUEL AND ASH CIRCUIT…………………………………13

2.2 AIR AND GAS CIRCUIT…………………………………..13

2.3 FEED WATER AND STEAM CIRCUIT………………….13

2.4 COOLING WATER CIRCUIT ……………………………13

CHAPTER 3 COAL HANDLING PLANT……………………15-22

3.1 INTRODUCTION……………………………………15

3.2 WAGON UNLOADING SYSTEM ………………....19

3.3 CRUSHING SYSTEM……………………………….21

3.4 CONSTRUCTION AND OPERATION ……………21

3.5 CONVEYING SYSTEM …………………………….22

CHAPTER 4 ASH HANDLING PLANT………………………23-30

4.1 COARSE ASH REMOVAL SYSTEM………………………23

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4.2 FLY ASH HANDLING SYSTEM……………………………23

4.3 BOTTOM ASH HANDLING SYSTEM ……………………..28

CHAPTER 5 ELECTRO-STATIC PRECIPITATOR……… 31-35

5.1 SCOPE AND PRINCIPLE OF OPERATION……………31

5.2 CONTROLLER ……………………………………………34

5.3 HIGH VOLTAGE RECTIFIER …………………………..34

5.4 ESP FIELD ………………………………………………….35

CHAPTER 6 BOILER…………………………………………. 37-46

6.1 BOILER CLASSIFICATION……………………………………..37

6.2 FURNANCE…………………………………… ………………….39

6.3 PULVERISED FUEL SYSTEM……………… ………………….39

6.4 FUEL OIL SYSTEM……………………………………………… 39

6.5 BOILER DRUM…………………………………………………… 40

6.6 DRAFT SYSTEM……………………………………………………41

6.7 DRAUGHT FAN…………………………………………………….41

6.8 ECONOMIZER………………………………………………………42

6.9 AIR-PREHEATER………………………………………………… 43

6.10 SUPERHEATER…………………………………………………. 44

6.11 REHEATER……………………………………………………….45

6.12 CIRCULATION SYSYTEM………………................................. 45

6.13 SOOT BLOWER………………………………………………….45

CHAPTER 7 STEAM TURBINE……………………………. 47-49

7.1 PRINCIPLE …………………………………… ………………..47

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7.2 DESCRIPTION OFSTEAMTURBINE…………………….. ..48

CHAPTER 8 TURBO GENERATOR……………………….50-53

8.1 THEORY…………………………………………………... 50

8.2 ROTOR………………………………………………………51

CHAPTER 9 COOLING SYSTEM……………………………54-55

9.1 INTRODUCTION…………………………………………….. 54

9.2 HYDROGEN DRYER………………………… ……………….55

CHAPTER10 EXCITATION SYSTEM……………………….56-57

10.1 FUNCTION OF EXCITATION SYSTEM…………………… 56

10.2 TYPES OF EXCITATION SYSTEM…………………………. 56

10.3 STATIC EXCITATION SYSTEM……………………………. 56

10.4 GENERAL ARRANGEMENT…………………………………57

CHAPTER 11 WATER TREATMENT PLANT………….…58-59

11.1 D.M. PLANT………………………………………………… 58

11.2 C.W.PLANT………………………………………………… 58

11.3 B.C.W PUMP HOUSE……………………………………… 59

CHAPTER 12 SWITCH YARD………………………………60-65

12.1 TYPES OF SWITCH YARD……………………………….60

12.2 COMPONENTS OF SWITCH YARD……………………60

CONCLUSIONS ………………………………………………. 66

REFERENCES ………………...……………............................ 67

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ACKNOWLEDGEMENT

It is a matter of great pleasure and priviledge for me to

present this report of 15 days on basis of practical knowledge gained by me during practical training at Dr.N.T.T.P.S , Vijayawada

during session 2016-2017. I with full pleasure converge my hearties thanks to Head of Mechanical Department, Malla Reddy Engg

College and to my guide Rahul , Assistant Engineer, Training institute Dr .N.T.T.P.S.

B.MOUNIKA

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CHAPTER-1

Dr. NARLA TATA RAO THERMAL POWER STATION

1.1 GENERAL:

Dr. Narla Tata Rao Thermal Power Station (Vijayawada Thermal Power Station) is located on the left bank of river Krishna with in a distance of 2 KM and is in between Ibrahimpatnam – Kondapalli Villages and 16 KMs of the North side of Vijayawada City in Krishna District.

The site lies at an elevation of about 26.5 Mtrs. Above the mean–sea-level.

Dr. Narla Tata Rao Thermal Power Station (Vijayawada Thermal Power Station) complex

consists of four stages. For Stage-I, II & III each stage consists of 2 x 210 MW Units and for Stage-IV the unit is of 500 MW rating. Stage-I, II, III & IV Units are commissioned as detailed

below:

Stage No. Unit No. Capacity Date of Commissioning

I 1

2

210 MW

210MW

01-11-1979

10-10-1980

II 3

4

210 MW

210MW

05-10-1989

23-08-1990

III 5

6

210 MW

210MW

31-03-1994

24-02-1995 IV 7 500 MW 06-04-2009

The total capacity of the station is 1760MW.

Dr. Narla Tata Rao Thermal Power Station (Vijayawada Thermal Power Station) is a unique one in the country, unique in its layout and numerous facilities provided for easy operation and maintenance.

The large reservoir created by the PRAKASAM Barrage provides an efficient Direct

Circulation Cooling Water System and also other requirements of the plant.

Originally the Dr. Narla Tata Rao Thermal Power Station (Vijayawada Thermal Power Station) is linked to Singareni Collieries Company Limited (S.C.C.L.) for supply of coal. The

average distance of S.C.C.L. coal fields by train is about 250 KM.

Dr.NTTPS, Stage-II,. III & IV are linked to Talcher Coal Fields in Orissa to meet the increased demand. The average distance of Talcher Coal Fields by train in 950 KMs.

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1.2 SPECIAL DESIGN FEATURES OF Dr.NARLA TATA RAO THERAML

POWER STATION (Vijayawada Thermal Power Station) :

STAGE-I:

The Coal bunkers and Mills are located in between the Boiler house and ESPs unlike usual arrangement elsewhere in the country, of placing the bunkers and mills in between the Turbine

House and Boiler. Thus, the Turbine House is completely isolated from the Mils to ensure dust – free atmosphere in the Turbine House and also to ensure easy accessibility of Mils of

maintenance. Multiple Flue Chimney is also a new feature at this Power Station.

STAGE – II & III:

1) The Second and Third Stage Boilers, Turbines and Generators are of a completely new design

TOWER Type Boilers of Single pass design manufactured by M/s B.H.E.L. under

collaboration with M/s. Stein Industries (France), KWU Turbines and Generators of West Germany design are installed in the Second and Third Stages.

2) TOWER TYPE BOILERS:

Among the advantages: Drainable heat exchangers and their edge over Two Pass Boilers

when using high ash content coals, lesser erosion of the heating surfaces compared to Two Pass Boilers etc. The spacing of the tubes and velocity of gases can be suitably adjusted at the Design

stage to achieve better results. Maintenance of this Boiler could be faster as there is no need for scaffolding or sky climber for maintenance of Super Heaters and Economizer.

3) DIRECT FIRED TUBE MILLS:

The Tube Mills can run for a very long time (Several thousand hours) without stopping as the forged balls are fed into the running mill while a vertical Bowl Mills is prone to frequent shut

downs due to its design consisting of several moving and wear parts with in system. Moreover the mill rejects system is completely dispensed with.

4) 6.6 KV Vacuum Circuit Breakers – Free from oils and Maintenance.

5) DISTRIBUTED DIGITAL CONTROL SYSTEMS (DCS):

Several advantages are there with Distributed Digital Control System as compared to conventional Hardwired system.The performance of the plant right from its commissioning has been highly satisfactory.

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STAGE –IV ( 1 x 500 MW):

The 7th Unit of Dr. N.T.T.P.S. with an installed capacity of 500 MW was synchronized with

grid on 06-04-2009. The commercial operation of the above unit was commenced form 28-01-2010.

Details of Capital / Investments made on each Stage:

SNo Stage Amount spent in crores

1 I ( 2 X 210 MW ) 193.00

2 II ( 2 X 210 MW ) 533.33

3 III ( 2 X 210 MW ) 840.00

4 IV ( 1 X 500 MW ) 2100.00

1.3 ALTERNATIVE COOLING WATER SYSTEM (A.C.W.S.):

The scheme of Alternative Cooling Water System was constructed in 2003-04 to facilitate repair works at Prakasam Barrage.

It is facilitating to deplete the reservoir level at PRAKASAM Barrage to still level i.e.

El+13.73 Mtrs. for about 3-4 months every year; during these months, the water requirement of Dr. N.T.T.P.S. is to be met by the Alternative Cooling Water System.

The Alternative Cooling Water System commissioned in March’2004 mainly consists of (a)

River Water Pump House at Bhavanipuram on the bank of River Krishna, to pump 1100 cusecs of water into existing cooling water canal (b) Three Nos. induced draft cooling towers in Dr. N.T.T.P.S premises to bring down the temperature of Hot Water to normal temperature so as to

re-circulate the same by adding into inlet canal through energy dissipation system and (C) Hot Water Pump House near Cooling Towers in Dr. N.T.T.P.S. premises to pump 1000 cusecs of

Hot Water into 3 cooling towers from Budameru Diversion Canal.

The Alternative Cooling Water System was completed at a cost of Rs.85 Crores. It was commissioned in March’2004.

1.4 Environment:

APGENCO is striving hard to maintain greener and cleaner atmosphere in and around the

Power House premises. 1,25,000 Nos. trees have been planted so far and further plantation on regular basis is being done. Ash is being issued free of cost for the users like, Cement / Asbestos industries and brick manufacturers. 2Nos. Brick manufacturing units at Dr. Narla Tata Rao

Thermal Power Station (Vijayawada Thermal Power Station) each with a capacity of 15,000 bricks per day for beneficial utilization of fly ash, have been in operation. So far utilization of

Ash up to 62% is achieved. APGENCO is advocating utilization of ash for better yield in agricultural sector and soil conservation and improving its fertility. Fly ash is being issued in

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large scale to farmers in Eluru, Nuziveedu and Ibrahimpatnam. The station has bagged ‘Green tech’ environment award for its best environment practices in the plant for the year 2013.

1.5 Performance:

The high level performance of Dr. N.T.T.P.S. has been a benchmark for the Power Sector in India; Winning & Awards at National level has been a routine for this unique power station. The station has received Meritorious Productivity Awards from the Government of India for the last

21 years consecutively and also Gold Medals for 12 years in a row. It has also got incentives for its Economic operation by improved Specific Oil Consumption / Auxiliary Consumption for 12

consecutive years.

His Excellency Dr. A.P.J. ABDUL KALAM, Hon’ble PRESIDENT OF INDIA presented a GOLD SHIELD to Dr. Narla Tata Rao Thermal Power Station (Vijayawada Thermal Power

Station) on 24-08-2004 at New Delhi in recognition of its outstanding performance for the period from 2000-01 to 2003-04.

In the year 2004-05, Capital overhaul works of Unit-I were carried out.

For the year 2005-06 V.T.P.S. was awarded Bronze Shield under Comprehensive Performance Award Scheme of GOI by the Hon’ble Prime Minister Sri Manmohan Singh on 21-

03-2007. Bronze shield could be bagged inspite of backing down of generation on the units to the tube of 692 MU to comply with the load dispatch instructions.

For year 2006-07 & 2008-09 also Dr. N.T.T.P.S. has bagged Bronze shield in recognition of

outstanding performance from the Ministry of Power, Govt. of India.

DR. Narla Tata Rao Thermal Power Station (Vijayawada Thermal Power Station) has accredited for ISO 9001:2008 Certification by M/s Lloyds Register Quality Assurance n May,

2010.

Dr. Narla Tata Rao Thermal Power Station (Vijayawada Thermal Power Station) continues to maintain its prominence among the best performing power stations in the Country.

Distinciton of Unit – V:

Unit-5 has recorded all time high financial year generation of 1818.35 MU with a PLF of

98.84% in 2009-10. This is the highest PLF ever achieved by any single unit of APGENCO in any financial year.

Unit III has established a grand record of 441 days of uninterrupted running from 14-12-

2004 to 28-02-2006 and proved its reliability as one of the best units in the country.

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Unit-I has also proved its unmatched reliability even after 27 years of service, by running continuously for 238 days from 09-12-2005 to 05-08-2006.

Dr. NARLA TATA RAO THERMAL POWER STATION Stage-V (1x800MW)

APGENCO has taken up the proposal for establishment of 1x800 MW Thermal Power

Project at Dr. NTTPS complex as a expansion unit. The unit is a coal based plant with super critical technology which is highly efficient and environment friendly, thus

minimizing Sox and NOXEmissions, ash generation.

APEGNCO and GoAP entered into MoU on 13-01-2012 during the Partnership Summit-2012 to take up 800 MW Unit at Vijayawada.

Detailed project Report for the project is ready.

The land requirement of the project is 315 acres. 85 acres of the land is readily available

for main plant and the additional land of 230 acres for the ash dyke will be acquired.

GoAP approval was received vide Lr.No. 1990 / Power.I(1)/2012-5, dt.30-01-2013.

Source of water is existing CW canal for the Dr. NTTPS and the water requirement for the project is 2000 M3 / hr.

A letter addressed to CEA for pre qualification and fixing inter-se priority on 26-05-2012.

The proposal for issue of coal linkage for 4.72 million tones per annum has been sent to

Ministry of coal vide letter dated 07-05-2012 along with the necessary application fee of Rs.5.0 lakhs.

Board approved to take up the project in 116th & 117th board meetings.

Airport Authority of India of issued of NOC for chimney on 03-10-2012.

TOR issued vide Lr.No. J-13012/26/2012-IA.II(T); dt.26-09-2012.

Entered PPA with APDISCOMs on 22-01-2013.

Public hearing was conducted on 10-01-2014.

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CHAPTER-2

COAL HANDLING PLANT

General Layout & Basic Idea

A control system of station basically works on Rankin Cycle. Steam is produced in Boiler is

exported in prime mover and is condensed in condenser to be fed into the boiler again. In

practice of good number of modifications are affected so as to have heat economy and to

increase the thermal efficiency of plant.

The Thermal Power Station is divided into four main circuits :

Fuel and Ash Circuit.

Air and Gas Circuit.

Feed water and Steam Circuit.

CoolingWater Circuit.

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2.1 Fuel & Ash Circuit:-

Fuel from the storage is fed to the boiler through fuel handling device. The fuel used in KSTPS

is coal, which on combustion in the boiler produced the ash. The quantity of ash produced is

approximately 35-40% of coal used. This ash is collected at the back of the boiler and removed

to ash storage tank through ash disposal equipment.

2.2 Air and Gas Circuit :-

Air from the atmosphere is supplied to the combustion chamber of Boiler through the action of

forced draft fan and induced draft fan. The flue gas gases are first pass around the boiler tubes

and super heated tubes in the furnace, next through dust collector (ESP) & then economizer.

Finally, they are exhausted to the atmosphere through fans.

2.3 FeedWater and Steam Circuit:-

The condensate leaving the condenser is first heated in low pressure (LP) heaters through

extracted steam from the lower pressure extraction of the turbine. Then its goes to dearator

where extra air and non-condensable gases are removed from the hot water to avoid pitting /

oxidation. From deaerator it goes to boiler feed pump which increases the pressure of the water.

From the BFP it passes through the high pressure heaters. A small part of water and steam is lost

while passing through different components therefore water is added in hot well. This water is

called the make up water. Thereafter, feed water enters into the boiler drum through economizer.

In boiler tubes water circulates because of density difference in lower and higher temperature

section of the boiler. The wet steam passes through superheated. From superheated it goes into

the HP turbine after expanding in the HP turbine. The low pressure steam called the cold reheat

steam (CRH) goes to the reheater (boiler). From reheater it goes to IP turbine and then to the LP

turbine and then exhausted through the condenser into hot

2.4 Cooling Water Circut:-

A large quantity of cooling water is required to condense the steam in condenser and marinating

low pressure in it. The water is drawn from reservoir and after use it is drained into the river

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CHAPTER-3

C0AL HANDLING PLANT

3.1 INTRODUCTION:-

Coal is the prime fuel for a thermal power plant.Hence adequate emphasis needs to be given for its proper

handling and a storage . Also,it is equally important to have a sustained flow of this fuel to maintain

uninterrupted power generation. Coal is transported to the power station by rail or road from the

mines.Loading as well as unloading of the wagons is automatic while the wagons are moving at a

predetermined speed. Coal is unloaded from wagons into track hopper . From the track hopper conveyor

takes coal to crusher for crushing.

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CONSTITUENTS OF COAL :-

CARBON :- 42.9%

HYDROGEN :- 2.96%

NITROGEN :- 0.91%

SULPHUR :- 0.33%

TRANSPORTATION OF COAL :-

BY RAILWAY

80-90% of the requirement is fulfilled by this way.

Safe mode of transport and fast delivery

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Demurrage calculations on Coal Rakes :-

We receive the coal wagons in the form of rakes [55-60 wagons in each rake]

Free time normally 7 hours from receipt of coal.

Free time is calculated from the receipt of written intimation of coal rakes from APGENCO

to the railway.

Rate of demurrage is Rs.100/wagon/hr.

ANALYSIS OF COAL :-

Sample of coal is randomly collected from each rake and detaled chemical analysis,calculation of

calorific value is carried out and is confirmed whether it is carried out and is agreementwith the coal

mines or not.

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Coal is received from singareni collaries and talcher (Orissa state).Coal wagons are received by rakes

of 58 wagons.The railways engine will place the loaded rake inside the Dr.NTTPS,at a sliding point

(placement point) and take away the empty wagons. Coal is also received in bottom discharge wagons

B.O.B.R – Bogies open bottom rapid discharge wagons.These wagons are unloaded on a track hopper

and from there,fed on to the underneath conveyers,by the paddle feeders, which will scoop the coal

from the hopper platform on to the running conveyer.

The coal handling plant can broadly be divided into three sections :-

1) Wagon Unloading System.

2) Crushing System.

3) Conveying System.

3.2 WAGON UNLOADING SYSTEM:-

3.2.1Wagon Tripler :-

It unloads the coal from wagon to hopper. 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 rollers roll with the help of a rope moving on pulley operated by a slip ring induction motor with

specification.

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Figure 3.1 WagonTripler

Rated Output. : 71 KW.

Rated Voltage. : 415 V.

Rated Current. : 14.22 Amp

Rated Speed. : 975 rpm

No. of phases. : 3

Frequency. : 50 Hz.

No. of Wagon Tripler : 5

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.

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3.3 CRUSHING SYSTEM:-

3.3.1Crusher House:-

It consists of crushers which are used to crush the coal to 20 mm. size. There are 10 Coal Crushers in

N.T.T.P.S.

There are mainly two type of crushers working in NTTPS:-

PrimaryCrushers i.e. i) Rail crushers or ii) Rotarybreaker.

SecondaryCrushers. i.e. Ring granulators.

3.3.1.1 PrimaryCrushers:-

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.

3.3.1.2 SecondaryCrusher:-

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.

3.4 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 gearboxby 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

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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 shaftmounted 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.

3.5 CONVEYING SYSTEM

3.5.1 Stacker Reclaimer :-

The stacker re-claimer unit can stack the material on to the pipe or reclaim the stack filed material and fed

on to the main line conveyor. While stacking material is being fed from the main line conveyor via

Tripler unit and vibrating feeder on the intermediate conveyor which feds the boom conveyor of the

stacker cum reclaimer. During reclaiming the material dis discharged on to the boom conveyor by the

bucket fitted to the bucket wheel body and boom conveyor feeds the material on the main line conveyor

running in the reverse direction.

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CHAPTER-4

ASH HANDLINGPLANT

This plant can be divided into 3 sub plants as follows:-

1) Coarse ash removal system

2) Fly ash handling system

3) Bottom Ash handling system

4.1COARSE ASH REMOVAL SYSTEM :-

Ash collected in four nos. of economizer hoppers will be removed once in a shift. The coarse ash hoppers

are divided in to 2 groups and each group of hoppers is operated one by one in sequence.

Each coarse ash hopper is provided with one number manually operated hopper isolation valve,

pneumatically operated valve, expansion joint and feeder ejector.

OPERATION OF CAR SYSTEM :-

The removal of coarse ash starts,as soon as removal of bottom ash is complete.Each group of coarse ash

hoppers are operated one by one in sequences.In auto mode of operation,the first group feeder ejector

water valve opens first.Knife gate valve connected to that group next,if adequate water pressure is

available.While closing,the knife gate valve closes first then feeder ejector water valve closes.Water valve

of next group in sequences opens,when the water valve,which was open,use fully closed.

Manual operation is also possible through the “close-open” control switch provided, “collect-Bypass”

switches are also provided for by passing any group of hoppers,When ash is not desired to be removed

during any particular operating cycle.

4.2FLY ASH HANDLING SYSTEM :-

Fly Ash Handling System, the major objective is to collect and transport the fly ash from the ash hoppers

of the ESP to the Fly ash silo or to the Ash Slurry making tank. Generally the power plants prefer Dry

Fly ash Disposal instead of making Ash Slurry from the Fly ash and the reason is that the fly ash collected

from the ESP Bottom Hopper is very fine and suitable for Cement making, if we are making slurry of it

then it will not be suitable for Cement making and economically also it is very good if you are selling the

Ash to the Cement Plants. So these are the reasons why most of the plants are going for Fly ash Disposal

instead of Slurry Disposal (Ash Water).

Slurry Type Fly Ash Disposal System: This is one of the simplest system for ash disposal from ESP

hopper to the slurry pond.High Pressure water and fly ash is mixed below the ESP hopper and below in

the diagram you can see that tapping for mixing of water is provided.

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Dry Type Fly Ash Disposal System: Fly Ash from the ESP Hoppers is collected in the Ash Vessels and

from there it is transported to the Fly Ash Silos by the help of Compressed air and from the Ash Silos, the

ash is transported to the Bulkers(Sealed Vessel Trucks).

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ESP Hopper: Hopper is a large conical type container used for dust or ash collection. After the field

charging in ESP we go for hammering of collecting plates and the fly ash deposited on the collecting

plates gets stored in the hopper. To ensure free flow of ash into the ash vessels from the hopper, the lower

portions of the hoppers are provided with electric heaters. Because if the temperature of the ash falls

below the ash fusion temperature then the ash will form big clusters and may choke the entire conveying

system.

Dome valve: It is situated between the ESP hopper and Ash vessel; it is a special type of valve which is

highly leak proof. It consists of a dome type structure with a rubber seal which is continuously getting

supply from the compressed air.

Air Vent Line: To remove the trapped air from the vessel, we use vent line and due to this line air from

the vessel is transported to Hopper and ash come down. It basically does two things, first of all by

removing the air from the vessel, it is removing the back-pressure from the Vessel and simultaneously it

is pressurizing the ash hopper.

Compressor: A compressed air station is set up in the plant. The compressed air station provides air for

the pneumatic conveying system and purging of fabric filters as we already explained in ESP. After

compressing the air, we have to remove all the moisture content from the air. To remove the moisture

from air we use Adsorbent Air Drier (AAD) and Refrigeration Air Drier (RAD).The pressure of the

compressor is depended on the system design.

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Ash Vessels: Ash vessels are present just below the ESP hoppers with the Dome Valve assembly.They

are supposed to contain the fly ash for a certain amount of time which will be carried to the fly ash

silos.Their ash holding capacity is depended on the conveying capacity of the ash line to the Ash Silos.

Fly Ash Silo: Fly Ash Silos store the fly ash generated by the Boiler in the maximum continuous

operating conditions (BMCR).The bottom of each fly ash silo is equipped with two ash discharging

chutes. One ash discharging chute is used for discharging the comprehensively used dry fly ash and the

other one is connected with a wet mixer, discharging the wet fly ash. The wet ash mixer is just a back-up

for the dry ash disposal system. Each fly ash silo is equipped with the bag filters and bag filter cleaning

facilities with exhaust fans.

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(Fly Ash Silos)

Air extraction fan: It is used to create a negative pressure inside the vessel of the silo and the air goes out through the bag filters.

Extractor: It is used to evacuate the Air from the Bulkers (Closed Vessel Truck), which

is connected to the ash disposal chute and the discharge is connected to ash vessel.

Diverting and dump valve: If one ash silo will not work we divert the line into another silo with the help of diverting valve and to dump the ash into ash silo dump valve is used.

Wet Fly Ash Disposal System:Up to the hopper part it is same as that of Dry Fly Ash handling system. After the hopper instead of going into the vessel, the ash gets mixed with a high Pressure

water and this mixture goes to a slurry tank for further pumping. The slurry formed is further pumped through a series of pumps or a single GEVO pump for dumping in the Ash yard. For

mixing of fly ash with water, a tapping is provided for High Pressure water below the hopper.

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4.3Bottom ash handling System :-

The bottom ash quantity is around 20% of the total Ash generation and there are mainly two

types of bottom ash disposal systems.

Dry Type Bottom Ash Disposal Wet Ash Slurry Disposal

Dry Type Bottom Ash Disposal: First of all we will discuss about the Dry type bottom ash

disposal system.

Submerged Scrapper Conveyor: Submerged Scraper Conveyor is used for cooling and

transmitting the hot bottom ash. The scraper conveyor used to send the bottom ash to the bottom ash silo. The Bottom ash hoppers are partially filled with water in order to avoid the direct impact of the Clinkers due to free fall. Whatever the ash, falling on the SSC conveyor is getting

scrapped by the scrappers to the clinker grinder.

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(Submersed Scrapper Conveyor)

Clinker Grinder: A clinker grinder is provided at the outlet of SCC to control the bottom ash size as in the bottom ash there will be some big clinkers and to make the ash of even size we use

a clinker grinder.The output of the bottom ash after the clinker grinder is around 25mm to 50mm,it is adjustable.

Drag Conveyor: It transmits the crusher output to the bottom ash silo. It is same as that of scrapper conveyor. Just for conveying purpose for the bottom ash.

Bottom ash silo: Each boiler is equipped with a bottom ash silo. It is used for storing the bottom

ash for a period of time and then it is dumped in the trucks for disposal.

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Slurry Type Bottom Ash Disposal:

Here the bottom ash from the 2nd pass of the Boilers goes to the Clinker Grinder in the 1st pass

by the help of high pressure water and from the Clinker Grinder all the ash goes to a slurry sump for further pumping.

BOILER PRESSURE PARTS

FAULTS IN GENERATOR

SSS)

http://www.power4you.co.in/2016/02/10/boiler-pressure-parts/

http://www.power4you.co.in/2016/03/18/generator-protection/

31

CHAPTER-5

ELECTRO-STATIC PRECIPITATOR

5.1 Scope &Principle of Operation:-

For general mankind, today an Eco friendly industry is must. As far as air pollution is concerned now a

days various flue gases filter are there in service. The choice depends on the size of suspended particle

matter. These filters are E.S.P. Fabric filter high efficiency cyclone separations and sitelling room. Fop fly

ash , where the particle size vary from 0.75 microns to 100 micron use gradually use E.S.P. to purify the

flue gases due to its higher efficiency & low running cost etc. In an ESP the dust lidder gas is passed

through an intense electric field, which causes ionization of the gases & they changed into ion while

traveling towards opposite charged electrode get deposited as particles and thus dust is electric deposited

an electrode creating the field.

ESP works on the principle of electrostatic attraction. In this phenomenon a negatively charged particle or

molecule is attracted to a positively charged molecule. In ESP, the flue gas passes into a chamber where

the individual particles of fly ash are given an electrical charge (Negative Charge) by the absorption of a

negative ion from a high voltage Negative DC ionizing field. So for that we have to provide a high

voltage of DC in a chamber where a high voltage negative corona will generate and all the particles will

be ionized.

Ionization of gases and charging of dust particles with the help of corona generation.

Movement of the particles to the collector plates & their Deposition

Removing particles from the collecting surface with the help of hammer.

Construction of ESP:

The ESP consists of two set of electrodes,

Thin wires called discharge or emitting electrodes

Collecting electrodes in the form of plates

The emitting electrodes are placed in between two plates (Collecting plates) and the emitting electrodes

are connected to the negative polarity of a high Voltage of DC source. The collecting electrodes are

connected to the positive of the source and grounded.

COMPONENTS OF ESP :-

Gas distribution screen: It is located at the inlet of the ESP. It is used to give an even distribution of gas over the precipitator’s entire cross sectional area.

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Collecting System:

Above we already explained about collecting system, basically used for the deposition of all the charged particulate matters. The upper edges are provided with hooks, which are hung from support welded to the roof structure.

The Lower end of every plate has a shock receiving provision. Collecting system are connected to the positive of the source and grounded.

Emitting System:

Emitting system is used for emit the ion to charge the particulate matter. Mostly it is a wire in

shape.

Rapping mechanism: Rapping mechanism is used in order to release/remove the deposited dust

particles from the collecting plate. It is of two types:

CERM: CERM stands for collecting electrode rapping mechanism. It consist tumbling hammer which is used to hammer the shock bar. Shock bar mounted at collecting plate lower end. When hammer hit the shock bar dust particles release from the collecting plate.

EERM: EERM stands for emitting electrode rapping mechanism. During ESP operation a fraction of the dust will be collected on the emitting electrode. it is therefore necessary to rap the emitting electrodes. The rapping mechanism for EERM is located on the roof.

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(Emitting Electrode Rapping Mechanism)

(Collecting Plate Rapping Mechanism)

Hopper:

Hopper is a large container used for dust or ash collection and lower portions of hoppers are

provided with electrical heaters.They are pyramidal in shape.

Electrical system:

As we know that ESP action required corona generation, Due to this we required high voltage DC (25kV-80kV).So we use rectifier transformer, who steps-up and rectifies the voltage.

Bag filter:

Flue gas (fine particles) enters the bag house and passes through fabric bags, which act as filter.

The bags are woven or felted cotton, synthetic or glass fiber material. Bags are supported by cages.

The separated fly ash is collected in a hopper from where this can be removed through mechanical screw conveyor or pneumatic conveying system.(Bag fabric = P84+ PTFE)

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5.2 CONTROLLER :-

Now a day micro-processor based intelligent controllers are used to regulate the power fed to the HVR.

The controls the firing / ignition angle of the thyristor connected in parallel mode. Input out waves of the

controller and HVR are also shown above, which clearly indicates that average power fed to ESP field

can be controlled byvariation of thefiring angle of thyristor. The output of controller with respect to time

is also controlled by microprocessor, so that ESP operation is smooth and efficient . The chars are as

shown: As can be seen in the event of spark between electrode the output of controller is reduced to zero

for few millisecond for quenching the spark. Controller also takes place care of fault in KVR and gives a

trapping and non-trapping alarm as per the nature of fault.

5.3 HIGH VOLTAGE RECTIFIER TRANSFORMER:-

HVR receives the regulated supply from controller. It steps up to high voltage rectifier. The D.C. supply

is fed to E.S.P. field through its negative bushing. The positive bushing so connected to earth through

small resistance which forms a current feed back circuit. A very high resistance column is also connected

with negative bushing . It forms the voltage feed back circuit. These two feedback are used in the

controller for indication and control purpose.

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5.4 E.S.P. FIELD:-

The field consists of emitting and collecting electrodes structure which are totally isolated from each

other and hanging with the top roof of field. The emitting is also isolated from the roof through the

support insulators which are supporting the emitting electrode frame works and also the supply to these

electrodes is fed through support insulators. The collecting electrodes are of the shape of flat plates. By

several similar plates which the emitting electrodes are of the shape of spring. Strong on the emitting

frame work with the help of hooks in both theends. The ash depositing on these electrode is rapped down

by separate wrapping mechanism happens at the bottom of the field. From these hoppers ash is

evacuated by ash handling system and dispose to the disposal area. The wrapping system is

automatically controlled with the help of the programmable metal controller, located in the ESP

auxiliaries control panels.

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CHAPTER-6

BOILER

A boiler (or steam generator) is a closed vessel in which water, under pressure is converted into steam. It

is one of the major components of a thermal power plant. A boiler is always designed to absorb maximum

amount of heat released in process of combustion. This is transferred to the boiler by all the three modes

of heat transfer i.e. conduction, convection and radiation.

FLOW CHART:-

Feed Water from Economizer → Boiler Drum → Low Temperature Super heater → Radiant

Super heater →Final Super heater → High pressure Turbine →Re-heater → Intermediate

Pressure Turbine →Low Pressure Turbine → Steam condenses in Condenser

6.1 Boilers are classified as:-

6.1.1 Fire tube boiler: -

In this type the products of combustion pass through the tubes which are surrounded by water.

These are economicalfor lowpressure only.

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6.1.2Water tubeboiler:-

In this type of boiler water flows inside the tubes and hot gases flow outside the tubes. These tubes are

interconnected to common water channels and to steam outlet.

water tube boilers have many advantages over the fire tube boiler

High evaporation capacity due to availability of large heating surface.

Better heat transfer to the mass of water.

Better efficiencyof plant owing to rapid and uniform circulationof water in tubes.

Better overall control.

Easy removal of scale from inside the tubes.

In NTTPS, Natural circulation, tangentially fired, over hanged type, Water tube boilers are used. Oil

burners are provided between coal burners for initial start up and flame stabilization. Firstly, light oil

(diesel oil) is sprayed for initialization then heavy oil (high speed diesel oil) is used for stabilization of

flame. Pulverized coal is directly fed from the coal mills to the burners at the four corners of the furnace

through coal pipes with the help of heated air coming from PA fan. Four nos. of ball mills of 34MT/hr.

capacity each have been installed for each boiler. The pressure inside boiler is -ive so as to minimized the

pollution and looses & to prevent the accidents outside the boiler.

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For ensuring safe operation of boilers, furnace safe guard supervisory system (FSSS) of combustion

engineering USA designed has been installed. This equipment systematically feed fuel to furnace as per

load requireme. The UV flame scanners installed in each of the four corners of the furnace, scan the flame

conditions and in case of unsafe working conditions trip the boiler and consequently the turbine. Turbine -

boiler interlocks safe guarding the boiler against possibility furnace explosion owing to flame failure.

6.2 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 turbulance, which causes

rapid mixing of fuel and air. In modern boilers,water-cooled furnacesare used.

6.3 PULVERISED FUEL SYSTEM:-

The boiler fuel firing system is tangentially firing system in which the fuel is introduced from wind

nozzle located in the four corners inside the boiler.

The crushed coal from the coal crusher is transferred into the unit coalbunkers where the coal is stored for

feeding into pulverizing mill through rotary feeder The rotary feeders feed the coal to pulverize mill at a

definite rate. Then coal burners are employed to fire the pulverized coal along with primary air into

furnace. These burners are placed in the corners of the furnace and they send horizontal streams of air and

fuel tangent to an imaginary circle in the center of the furnace. Figure6.2 Pulverised System

6.4 Fuel Oil System:-

The functional requirement of the fuel burning system is to supply a controllable and uninterrupted

flammable furnace input of fuel and air and to continuously ignite and burn the fuel as rapidly as it is

introduced into the furnace. This system provides efficient conversion of chemical energy of fuel into heat

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energy. The fuel burning system should function such that fuel and air input is ignited continuously and

immediately upon its entry into furnace.

The Fuel air (secondary air) provided FD fan, surrounds the fuel nozzles. Since this air provides covering

for the fuel nozzles so it is called as mantle air. Dampers are provided so that quantity of air can be

modulated. Coal burners distribute the fuel and air evenlyin the furnace.

Ignition takes place when the flammable furnace input is heated above the ignition temperature. No

flammable mixture should be allowed to accumulate in the furnace. Ignition energyis usuallysupplied in

the form of heat.This ignition energyis provided by oil guns and by igniters.

6. 5 Boiler Drum :-

The drum is a pressure vessel. Its function is to separate water and steam from mixture (of steam & water)

generated in the furnace walls. It provides water storage for preventing the saturation of tubes. It also

houses the equipment needed for purification of steam. The steam purification primarily depends on the

extent of moisture removal, since solids in steam are carried by the moisture associated with it. The drum

internals reduce the dissolved solids content of the steam to below the acceptable limit. drum is made up

of two halves of carbon steel plates having thickness of 133 mm.

The top half and bottom half are heated in a plate heating furnace at a very high temperature and are

pressured to form a semi cylindrical shape. The top and bottom semi cylinders with hemispherical dished

ends are fusion welded to form the boiler drum. The drum is provided with stubs for welding all the

connecting tubes i.e. down comer stubs, riser tubes stubs and super-heater outlet tube stubs.

Boiler drum is located at a height of 53m from ground. The drum is provided with manholes and manhole

covers. Manhole is used for facilitating the maintenance person to go inside the drum for maintenance.

The drum form the part of boiler circulating system i.e. movement of fluid from the drum to the

combustion zone and back to boiler drum. Feed water is supplied to the drum from the economizer

through feed nozzles. Water from the drum goes to water walls through six down comers.

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Main parts of boiler drum are:-

1. Feed pipe

2. Riser tube

3. Down comer

4. Baffle plate

5. Chemical dosing pipe

6. Turbo separation

7. Screen dryer

8. Drum level gauge

6.6 DraftSystem:-

The combustion process in a furnace can take place only when it receives a steady flow of air and has the

combustion gases continuously removed. Theoretically balanced draft means keeping furnace pressure

equal to atmospheric pressure, but in practice the furnace is kept slightly below atmospheric pressure. It

ensures that there is no egress of air or hot gas and ash into boiler house.

6.7 Draught Fans:-

A fan can be defined as volumetric machine which like pumps moves quantities of air or gas from one

place to another. In doing this it overcomes resistance to flow by supplying the fluid with the energy

necessary for contained motion. The following fans are used in boiler house.

6.7.1 Primary air fan (P.A. fan) or Exhauster fan :-

Pulverized coal is directly fed from coal mills to the burners at the four corners of the furnace through

coal pipes with the help of heated air coming from PA fan. Secondly, this fan also dries the

coal.Usuallysized for 1500 RPM due to high pressure.

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6.7.2 Forced draught fan (F.D. fan):-

The combustion process in the furnace can take place only when it receives a steady flow of air. This air

is supplied by FD fan. Thus FD fan takes air from atmosphere at ambient temperature & so provides

additional draught. Its speed varies from 600-1500 RPM.

6.7.3Induced Draught fan (I.D. fan):-

The flue gases coming out of the boiler are passed to the ESP & then dust free gases are discharged up by

the chimney to the atmosphere through the ID fan.

6.8 Economizer:-

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The flue gases coming out of the boiler carry lot of heat. An economizer extracts a part of this heat from

the flue gases and uses it for heating the feed water before it enters into the steam drum. The use of

economizer results in saving fuel consumption and higher boiler efficiency but needs extra investment. In

an economizer, a large number of small diameter thin walled tubes are placed between two headers. Feed

water enters the tubes through the other.The flue gases flowoutside the tubes.

6.9 Air preheaters:-

Air preheaters are employed to recover the heat from the flue gases leaving the economizer and are used

to heat the incoming air for combustion. This raises the temperature of the furnace gases, improves

combustion rates an efficiency and lowers the stack (chimney) temperature, thus improving the overall

efficiency of the boiler. Cooling of flue gasesby20% raises the plant efficiencyby1%. Air preheaters are

employed to recover the heat from the flue gases leaving the economizer and are used to heat the

incoming air for combustion. This raises the temperature of the furnace gases, improves combustion rates

and efficiency and lowers the stack (chimney) temperature, thus improving the overall efficiency of the

boiler. Cooling of flue gasesby20% raises the plant efficiencyby1%.

In NTTPS regenerative type of preheater is used. They use a cylindrical rotor made of corrugated steel

plate. The rotor is placed in a drum which is divided into two compartments, i.e. air compartment

(primary air coming from primary air fan and secondary air for air coming from FD fan with + ive

pressure) and flue gases (from economizer with – ive pressure) compartments. To avoid leakage from one

compartment to other seals are provided.

The rotor is fixed on an electrical shaft rotating at a speed of 2 to 4 rpm. As the rotor rotates the flue

gases, are pass through alternatively gas and air zone. The rotor elements are heated by flue gases in their

zone and transfer the heat to air when they are in air zone. The air temperature required for drying in the

case of coal-fired boiler decided the size of the air heaters

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6.10Super heater:-

Superheated steam is that steam, which contains more heat than the saturated steam at the same pressure

i.e. it, has been heated above the temperature corresponding

to its pressure. This additional heat provides more energy to the turbine and thus the electrical power

output is more.

A super heater is a device which removes the last traces of moisture from the saturated steam leaving the

boiler tubes and also increases its temperature above the saturation temperature.

The steam is superheated to the highest economical temperature not only to increase the efficiencybut

also to have following advantages –

Reduction in requirement of steam quantity for a given output of energy owing to its high

dry so the mechanical resistance to theflowof steam over them is small resulting in high

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6.11 Re-heater:-

Re-heaters are provided to raise the temperature of the steam from which part of energy has already been

extracted by HP turbine. This is done so that the steam remains dry as far as possible through the last

stage of the turbine. A re-heater can also be convection, radiation or combination of both.

6.12 Circulation System :-

In natural circulation system, water delivered to steam generator from header, which are at a temperature

well below the saturation value corresponding to that pressure. After header, it is delivered to economizer,

which heated to above the saturation temperature.

From economizer the water enters the drum and thus joins the circulation system through down covering

water wall tubes. In water wall tubes a part of the water is converted to steam due to boiler and the

mixture flows back to the drum. In the drum, the steam is separated out through the steam separators and

passed to the super heater. After the super heater when the steam temperature becomes high and pressure

upto 150 Kg./cm3 steam is allowed to enter the turbine to convert potential energy to kinetic energy.

6.13Soot Blower:-

The boiler tubes are cleaned with the help of steam by the process called soot blowing. We are well

known that a greater no. of tubes are presented inside the boiler. Slowly and slowly the fine ash particles

are collected on the tube surface and from a layer this is called soot. Soot is a thermal insulating material.

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There are mainly three types of soot blower are used in NTTPS: -

1. Water wall soot blower

2. Super heater sootblower

3. Air pre heater soot blower

GENERAL DESCRIPTION:-

Boilers are tangentially fired, balance draft, natural circulation , radiant type, dry bottom with direct fired

pulverized coal from bowl mills. They are designed for burning low grade coal with high ash content. Oil

burners are located between coal burners for flame stabilization. Pulverized coal is directly fed from the

coal mills to the burners at the four corners of the furnace through coal pipes. The pulverized fuel pipes

from the mills to the bunkers are provided with basalt lined bends to reduce erosion and to improve the

life of these pipes owing to poor grade of coal there is a high percentage of mill rejects. The mill rejects

are conveyed in a sluice way to an under- ground tank. From this tank the mixture is taken to an overhead

hydro-bin where water is decanted and the mill reject are disposed off by trucking. ESP with collection

efficiency of 99.8% have been provided to reduce environmental pollution and to minimize induce draft

fan wear. A multi-flue reinforced concrete stack with two internal flues has been provided. Two boiler

feed pumps each of 100 % capacity are driven by AC motor through hyd. coupling with scoop tube

arrangement for regulating feed water pressure for each unit. The air required for combustion is supplied

by two forced draft fans. Due to anticipated high abrasion of ID fans impellers. Three ID fans each of

60% capacity have been provided one ID fan to serve as standby. For ensuring safe operation of boilers,

furnace safe guard supervisory system (FSSS) of combustion engineering USA designed has been

installed. This equipment systematicallyfeedfuel to furnace as per load requirement. The UV flame

scanners installed at two elevation in each of the four corners of the furnace, scan the flame conditions

and in case of unsafe working conditions but out fuel and trip the boiler and consequently the turbine.

Turbine – boiler interlocks safe guarding the boiler against possibilityfurnace explosion owing to flame

failure. Facilities have been provided to simultaneously unload and transfer 10 light oil and 40 heavy oil

tankers to the designated tanks. Oil preheating arrangement is provided on the tanks floors for the heavy

oil tanks. Superheated steam temperature is controlled by attemperation. Re-heater steam temperature is

primarily by tilting fuel burners through + 30o and further control if necessaryis done by attemperation.

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CHAPTER-7

STEAMTURBINE

7.1 INTRODUCTION:-

Turbine is a machine in which a shaft is rotated steadily by impact or reaction of current or stream of

working substance (steam, air, water, gases etc) upon blades of a wheel. It converts the potential or

kinetic energy of the working substance into mechanical power by virtue of dynamic action of working

substance. When the working substance is steam it is called the steam turbine.

PRINCIPAL OF OPERATION OFSTEAM TURBINE:-

Working of the steam turbine depends wholly upon the dynamic action of Steam. The steam is caused to

fall in pressure in a passage of nozzle doe to this fall in pressure a certain amount of heat energy is

converted into mechanical kinetic energy and the steam is set moving with a greater velocity. The rapidly

moving particles of steam, enter the moving part of the turbine and here suffer a change in direction of

motion which gives rose to change of momentum and therefore to a force. This constitutes the driving

force of the machine. The processor of expansion and direction changing may occur once or a number of

times in succession and may be carried out with difference of detail. The passage of steam through

moving part of the commonly called the blade, may take place in such a manner that the pressure at the

outlet side of the blade is equal to that at the inlet inside. Such a turbine is broadly termed as impulse

turbine. On the other hand the pressure of the steam at outlet from the moving blade may be less than that

at the inlet side of the blades; the drop in pressure suffered by the steam during its flow through the

moving causes a further generation of kinetic energy within the blades and adds to the propelling force

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which is applied to the turbine rotor. Such a turbine is broadly termed as impulse reaction turbine. The

majority of the steam turbine have, therefore two important elements, or Sets of such elements . These are

(1) the nozzle in which the system expands from high pressure end a state of comparative rest to a lower

pressure end a status of comparatively rapid motion. The blade or deflector , in which the steam particles

changes its directions and hence its momentum changes . The blades are attach to the rotating elements

are attached to the stationary part of the turbine which is usually termed the stator, casing or cylinder.

Although the fundamental principles on which all steam turbine operate the same, yet the methods where

by these principles carried into effect very end as a result, certain types of turbine have come into

existence.

1. Simple impulse steam turbine.

2. The pressure compounded impulse turbine.

3. Simple velocitycompounded impulse turbine.

4. Pressure-velocitycompounded turbine.

5. Pure reaction turbine.

6. Impulse reaction turbine.

7.2 Description of Steam Turbines:-

7.2.1 Steam flow:-

210 MW steam turbine is a tandem compound machine with HP, IP & LP parts. The HP part is single

flow cylinder and HP & LP parts are double flow cylinders. The individual turbine rotors and generator

rotor are rigidly coupled. The HP cylinder has a throttle control. Main steam is admitted before blending

by two combined main stop and control valves. The HP turbine exhaust (CRH) leading to reheated have

tow swing check valves that prevent back flow of hot steam from reheated, into HP turbine. The steam

coming from reheated called HRH is passed to turbine via two combined stop and control valves. The IP

turbine exhausts directlygoes to LP turbine bycross groundpipes.

7.2.2 HP Turbine:-

The HP casing is a barrel type casing without axial joint. Because of its rotation symmetry the barrel type

casing remain constant in shape and leak proof during quick change in temperature. The inner casing too

is cylinder in shape as horizontal joint flange are relieved by higher pressure arising outside and this can

kept small. Due to this reason barrel type casing are especially suitable for quick start up and loading.The

HP turbine consists of 25 reaction stages. The moving and stationary blades are inserted into

appropriately shapes into inner casing and the shaft to reduce leakage losses at blade tips.

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7.2.3 IP Turbine:-

The IP part of turbine is of double flow construction. The casing of IP turbine is split horizontally and is

of double shell construction. The double flow inner casing is supported kinematically in the outer casing.

The steam from HP turbine after reheating enters the inner casing from above and below through two

inlet nozzles. The centre flows compensates the axial thrust and prevent steam inlet temperature affecting

brackets, bearing etc. The arrangements of inner casing confines high steam inlet condition to admission

branch of casing, while the joints of outer casing is subjected only to lower pressure and temperature at

the exhaust of inner casing. The pressure in outer casing relieves the joint of inner casing so that this joint

is to be sealed only against resulting differential pressure. The IP turbine consists of 20 reaction stages per

flow. The moving and stationary blades are inserted in appropriately shaped grooves in shaft and inner

casing.

7.2.4 LP Turbine:-

The casing of double flow type LP turbine is of three shell design. The shells are axially split and have

rigidly welded construction. The outer casing consist of the front and rear walls , the lateral longitudinal

support bearing and upper part. The outer casing is supported by the ends of longitudinal beams on the

base plates of foundation. The double flow inner casing consist of outer shell and inner shell. The inner

shell is attached to outer shell with provision of free thermal movement. Steam admitted to LP turbine

from IP turbine flows into the inner casing from both sides through steam inlet nozzles.

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CHAPTER– 8

TURBOGENERATOR

8.1THEORY

TURBO GENERATOR manufactured by B.H.E.L. and incorporated with most modern design concepts

and constructional features, which ensures reliability, with constructional & operational economy.

The generator stator is a tight construction, supporting & enclosing the stator windings, core and

hydrogen coolers. Cooling medium hydrogen is contained within frame & circulated by fans mounted at

either ends of rotor. The generator is driven by directly coupled steam turbine at a speed of 3000 r.p.m.

the Generator is designed for continuous operation at the rated output. Temperature detectors and other

devices installed or connected within then machine, permit the windings, teeth core & hydrogen

temperature, pressure & purity in machine under the conditions. The source of excitation of rotor

windings is thyristor controlled D.C. supply. The auxiliary equipment‟s supplied with the machine

suppresses and enables the control of hydrogen pressure and purity, shaft sealing lubricating oils. There is

a provision for cooling water in order to maintain a constant temperature of coolant(hydrogen) which

controls the temperature of windings.

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8.2 ROTOR :-

8.2.1 STATOR FRAME:-

The stator frame of welded steel frame construction, which gives sufficient & necessary rigidity to

minimize the vibrations and to withstand the thermal gas pressure. Heavy end shields enclose the ends of

frame and form mounting of generator bearings and radial shaft seals. Ribs subdivide the frame and axial

members to form duct from which the cooling gas to & fro radial ducts in the core and is re-circulated

through internally mounted coolers. All the gas ducts are designed so as to secure the balanced flow of

hydrogen to all parts of the core. The stator constructed in a single piece houses the core and windings.

The horizontally mounted water cooled gas coolers being so arranged that it may cleaned on the water

side without opening the machine to atmosphere. All welded joints exposed to hydrogen are specially

made to prevent leakage. The complete frame is subjected to hydraulic test at a pressureof 7ATA.

8.2.2 STATOR CORE:-

It is built up of special sheet laminations and whose assembly is supported by a special guide bass. The

method of construction ensures that the core is firmly supported at a large number of points on its

periphery. The laminations of high quality silicon steel which combines high permeability with low

hysteresis and eddy current losses. After stamping each lamination is varnished on both sides with two

coats. The segment of insulating material is inserted at frequent intervals to provide additional insulation.

The laminations are stamped out with accurately fine combination of ties. Laminations are assembled on

guide bass of group separated by radial ducts to provide ventilation passage. The ventilation ducts are

disposed so as to distribute the gas evenly over the core & in particularly to give adequate supports to the

teeth. At frequent intervals during stacking the assembled laminations are passed together in powerful

hydraulic press to ensure tight core which is finally kept between heavy clamping plates which are non-

magnetic steel. Use of non-magnetic steel reduces considerably by heating of end iron clamping. The

footed region of the core is provided by pressing figures of non-magnetic steel, which are welded to the

inner periphery of the clamping plates. In order to reduce the losses in the ends packets special dampers

are provided at either ends of core. Mostly dampers are provided to prevent hunting in ac machines.

51

8.2.3 STATOR BARS:-

Stator bars are manufactured as half bars. Each stator half coil is composed of double glass cover and bars

of copper transposed in straight portion of “Robill Method” so that each strip occupies every radial

portion in the bar. For an equal length along the bar. They are made in strips to reduce skin effect. The

winding overhead is in volute shape. The overhung portion of the bar is divided into four quadrants &

insulated. The arrangement reduces additional losses due to damping currents which otherwise be present

due to self- induced non-uniform flux distribution in the coil slots. The main distribution for the bar

consists of resin rich mica loosed thermosetting epoxy. This has excellent mechanical and electrical

properties & does not require any impregnation. Its moisture absorbing tendency is very low and behavior

of mica is for superior than any other conventional tape insulation system. Semi-conductor coating is also

applied to a part of overhung with a straight overlap of conductive coil in the sides to reduce eddy

currents to minimum. Conductor material is electrolytic copper connections brazed with free coating

silver alloy to obtain joints, which are both electrically& mechanicallysound.

8.2.4 STATOR WINDINGS

Stator windings are double star layers, lap wound, three phase, and short pitch type. The top & bottom are

brazed and insulated at either end to form turns. Several such turns form a phase. Phases are connected to

form a double star winding. The end of winding form involutes shape ends, inclined towards machine

axis by 20o, thus form a basket winding with total induced conical angle of 400 . Due to this stray load

losses in the stator ends to zero. The arrangement of complete stator winding electrical circuit is viewed

from turbine end of generator & rotor windings. Slot numbering is clockwise from turbine end. A thick

line identifies the top bar in slot No.1. End windings will be sealed against movement of short circuit by

both axial & peripheral bracing. The later consists of hardened glass laminated blocks inserted between

adjacent coil sides in coil overhangs, so that with the coils, they form a continuous rigid ring. Glass cord

or top is used lashing the packing of blocks. The complete assembly is secured b y high tensile brass

blots. The winding is designed to withstand short circuit stresses. The exposed portion of windings is

finally coated. Insulation of individual bars & stator windings at various stresses is tested with applied

high voltages of AC of Hz.

8.2.5TERMINAL BUSHINGS

Six output leads (3 long, 3 short) have been brought out of the coming on the exciter side. External

connections are to be made to the three shorter terminals, which are phase terminals. The large terminals

are of neutral & current transformer is inserted. The conductor of Generator terminal bushing having

hollow copper tubes with Copper brazed at the ends to avoid leakage of hydrogen. Hollow portions

enable bushings to be hydrogen cooled. Ends of bushings are Silver-plated: middle portion of the bushing

is adequately insulated & has a circular flange for bolting the stator casing. Gaskets are provided

between the Flange of terminal bushings andcastings to make it absolutely gas tight.

8.2.6 BEARINGS

Generator bearings have electrical seats of consists of steel bodies with removable steel pads. The

bearings are formed for forced lubrication of oil at a pressure of 2-3 ATM/ from the same pump that

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supplies oils to the turbine, bearings & governing gears. There is a provision to ensure & measure the

rotor bearing temperature by inserting a resistance thermometer in the oilpockets.

8.2.7 VENTILATION SYSTEM

The machine is designed with ventilation system having 2 ATM rated hydrogen pressure. Two axial fans

mounted on either side of the rotor to ensure circulation of hydrogen. The stator is designed for radial

ventilation by stem. The end stator core packets & core clamping & plates are intensively cooled by

Hydrogen through special ventilation system. Design of special ventilation is so as to ensure almost

uniform temperature of rotor windings and stator core. Rated load operating temperature is well within

the limits corresponding to the Class B operation. Embedded Resistance Temperature Detectors do

continuousmonitoringof Hydrogen temperature at active parts of Generator.

8.2.8RESISTANCE TEMPERATURE DETECTORS (R.T.D.)

An R.T.D. is a point resistance element. Operation of R.T.D. depends on the principal that electrical

resistance of metallic conductor varies linearly with temperature.

8.2.9 APPLICATIONS

RTD & its associated equipments are designed for use with Generator to determine temperature at various

parts & places.The equipment‟sconsistsof two parts:-

1. Switch Board Equipment: is usually includes a temperature indicating meter, test resistor transfer

switch & leads.

2. Machine Equipment: is usually includes temperature R.T.D.leads and terminal blocks with grounding

connect

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CHAPTER– 9

COOLINGSYSTEM

9.1 INTRODUCTION:-

In NTTPS hydrogen cooling system is employed for generator cooling. Hydrogen is used for cooling

medium primarily because of its superior cooling properties & low density. Thermal conductivity of

hydrogen 7.3 times of air. It also has higher transfer co-efficient . Its ability to transfer heat through

forced convection is about 75% better than air. Density of hydrogen is approx. 7/14 of the air at a given

temperature and pressure. This reduces the wind age losses in high speed machine like turbogenerator.

Increasing the hydrogen pressure the machine improve its capacity to absorb & remote heat. Relative

cooling properties of air and hydrogen are given below:-

1) Elimination of fire risk because hydrogen will not support combustion.

2) Corona discharge is not harmful to insula. since oxidation is not possible.

3) Smooth operation of machine in view of vertical elimination of wind age noise & the use of heavygas

light enclosure and dirty probe casing.

At pressure 0.035 atm. of hydrogen heat carrying capacity is 1. But at 2.0atm. of hydrogen heat

carrying capacity is 1.95 to overcome the serious possibility of hydrogen explosion with in the machine

and to ensure the safety of operation purity of hydrogen on the generator. Casing must be maintained as

high as possible. The purity of hydrogen should be 98% above but should not be less than 98% . In case

of hydrogen puritydrops below98% an alarm is provided.

9.2 HYDROGEN DRYERS:-

Two nos. of dryers are provided to absorb the hydrogen in the Generator. Moisture in this gas is absorbed

bysilica gel in the dryer as the absorbed gas passes through it. The satural of silica gel is indicated by

change in its color from blue to pink. The silica gel is reactivated byheating. Bysuitable change over from

drier to the other on un-interrupted drying is achieve.

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55

CHAPTER-10

EXCITATIONSYSTEM

The electric power Generators requires direct current excited magnets for its field system. The excitation

system must be reliable, stable in operation and must response quickly to excitation current requirements.

When excitation system response is controlled by fast acting regulators, it is chiefly dependent on exciter.

Exciter supply is given from transformer and then rectified.

10.1 Function of excitation system:-

The main function of excitation system is to supply required excitation current at rated load condition of

turbo Generator. It should be able to adjust the field current of the Generator, either by normal controller

automatic control so that for all operation & between no load and rated load. The terminal voltage of the

system machine is maintained at its value. The excitation system makes contribution improving power

system stability steady state condition. The excitation system that are commonly termed quick response

system and have following principal feature :- Exciter of quick response & high voltage of not less than

1.4 times the rated filed voltage and nominal exciter response of minimum 0.5.

10.2 Type of Excitation System:-

There have been manydevelopments in excitation system design. There has been continuing reac makes

turbo-generator I. Conventional DC excitation system. Brushes excitation system.

10.3 STATIC EXCITATION SYSTEM :-

In NTTPS static excitation system is provided it mainlyconsists of the following:-

1) Rectifier transformer.

2) Nos. of thyristor converters.

3) An automatic voltage regulator (AVR).

4) Field suppression equipment

5) Field flashing equipment.

10.4 GENERAL ARRANGEMENT:-

In the excitation system the power required for excitation of Generation are tapped from 11 KV bus ducts

through a step down rectifier transformer. After rectification in thermistor, converter, the DC power is fed

to the Generator field winding through a field breaker. The AVR control the o/p from thyristor converter

by adjusting the firing angle depending upon Generator voltages. The field flashing system facilitates

initial built up of the Generator voltage from the static AC or DC supply

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10.4.1 RECTIFIER TRANSFORMER :-

Transformer steps down the bus voltage 11 KV to 640 V and has a rating of 1360 KVA. It is dry type, it

is however provided with current relays and two temperature sensors.

10.4.2 ATHYRISTOR CONVERTOR:-

The thyristor panel and are intended for controlled rectification of AC Input power. 6. Thyristor converter

are connected in parallel each rates for continuous current o/p of 20 % of the rated capacity i.e. 20 %

reserve. Each thyristor converter consists of 6 thyristor connected in 3-3 , full wave, 6-pulse bridge from

and they are cooled byfans provided with a fuse for protection against shortcircuit.

10.4.3 AUTOMATIC VOLTAGE CONTROLS :-

The AVR is transistorized thyristor controlled equipment with very fast response. The AVR is also

having provision of stator and rotor currents limits and load angle limits for optimum utilization of

lagging and leading reactive capacities of generator.

10.4.4 FIELDSUPRESSIONEQUIPMENT:-

The field equipment consists of a field breaker with discharge resistors. The field breakers have 4 main

breaking contacts and two discharge contacts, which close before main contact break.

(a) A veryfast response.

(b) Extremelyreliable in view of static components.

(c) Lowmaintenance cost

(d) High efficiency.

(e) Fast field suppression through field and discharge resistance as well as through Thyristor Bridge,

feeding the Generator field.

10.5 OPERATION:-

After bringing the speed to operation speed say 3000 r.p.m. , the voltage is slowly built up with the help

of excitation system. This action is taken for synchronizing the Generator. 10.5.1 SYNCHRONIZING:-

For synchronizing the Generator to the grid system 5 condition of equality have to be satisfied. These are

(I)_Voltage (II) Frequency (III) Phase displacement (IV) Phase sequence (V) Wave form. Wave form and

phase sequence of the Generator are determined at the design of each connectionSYNCHRONIZING of

the generator.

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CHAPTER– 11

WATER TREATMENT PLANT

The principle problem in high pressure boiler is to control corrosion and steam quality. Internal corrosion

costs power station crores of rupees in repair without strict control impurities in steam also form deposit

over turbine blades and nozzles. The impurities present in water are asfollows :-

1) Un-dissolved and suspended solid materials

2) Dissolved slats and minerals.

3) Dissolved gases

4) Other minerals ( oil, acid etc

5). a) Turbidity& Sediment. b) Silica.c) Micro Biological. d) Sodium & Potassium Salt. e) Dissolved

Sales Minerals.

6). a) O2gas. b) CO2 gas.

11.1 D.M. PLANT:-

In this plant process water is fed from all these dissolved salts. Equipment for demineralization cum

softening plant is supplied and erected by M/s. Wanson (India) Ld., Pune. This plant consists of two

streams each stream with activated carbon filter, weak acid , cation exchanger and mixed bed exchanger.

The filter water to DM plant through 250 dia. header from where a heater top off has been taken to

softening plant. Two filtered water booster pumps are provided on filtered water line for meeting the

pressure requirement in DM Plant. Sodium Sulphate solution of required strength is dosed into different

filtered water by mean of dosing pump to neutralize chlorine prior to activated carbon filter. When water

passed an activated carbon filter will remove residual chlorine from water. Provision is made for back

washing the activated carbon filter. When pressure drop across filter exceeds a prescribed limit from the

activated carbon filter the works acid cation unit. The deception water the weak base anion exchanger unit

water then enters de-gasified unit where free CO2 is scrubbed out of water by upward counter flow of low

pr. air flow through degasified lower and degassed water is pumped to strong base exchanger ( anion

exchanger). Arrangement for dosing ammonia solution into de-mineralized water after mixed bed unit has

been provided p+1 correction before water is taken in de-condensate transfer pump the DM water to unit

condensor as make up.

11.2 C.W. PLANT:-

Circulating water pump house has pumps for condensing the steam for condensor. Five pumps are used

for condensing Unit No.1 & 2 and after condensing this water is discharged back into the river. Each

pump has capacity of 8275 M3/Hr, and develop pressure about 1.94 Kg./Cm2.Three seal water pump are

used for sealing circulating water pump shaft at pr. 4.5 kg./cm2. Two pump for unit 1 & 2 with one stand

by is used for supplying raw water to chlrofied chemical dosing is tone between and chlorified water is

58

taken through main line. From main line water passes through filter bed to filter the water. Chlorified

water is pumped to 42 m elevation by two pumps of capacity 270 M3/Inch at discharge pressure of 6.9

Kg./Cm2. At 42 M elevation the water is stored in tank and used for cooling the oil coolers and returned

back to river. Oil coolers are situated on ground and there are no. of tress for each unit.

11.3 B.C.W. PUMPHOUSE:-

Filter water after demineralization is used for bearing cooling from BCW pump house after passing

through strainer and heat exchanger it enters at 30-32oC and leave exchanger at 38oC. The raw water

used in ash handling plant and remaining quantity is stored in sumps of BCW Pump House. From here the

water is pumped to CW Pump by TWS (Traveling water screens) pumps are run by motors of 90 KW and

has a capacity of 240 Cum/hr/pump at pressure of 5 kg/cm2. BCW here stand for water used for cooling

oil used for cooling the bearing. In CW pump house water is discharged from nozzle and impinged for

traveling water screens for cleaning it

59

CHAPTER-12

SWITCH YARD

Definition: The main function of switchyard is to transmit & distribute the power at incoming

voltage from the generating station and provide facilities of switching by the help of switchgears.

Earlier we have explained about the various types of switchgears in our previous

article.Switchyard is the point in the power network where transmission lines and distribution

feeders or generating units are connected through circuit breakers and other switchgears via bus

bars and transformers. Switchyard acts as interface between the power plant electrical system

and electrical grid.

12.1Types of Switchyard :-

AIS (Air Insulated Switchyard): This is the most common type of switchyard; here the

switchyard is present outside and open to the atmosphere. The high voltage lines are

isolated by the air, for that reason they occupy more space as compared to the GIS.

GIS (Gas Insulated Switchyard): This type of switchyard is generally found where the

space available is very less and they are generally located inside a closed room with

proper isolation. The high voltage cables are kept inside the duct with insulation.

12.2 Components of Switchyard:-

Gantry Structures: Gantry structures are made of steel and are used to support high voltage

conductors throughout the substations that interconnect sections of electrical equipment. In

general there are two types of gantry structures and out of them Tubular gantary is mostly used

in switchyards as it takes lesser time for installation and easy to install.

60

Bus-bar: Bus-bars receive the power from incoming circuits or we can say a grid and deliver the

power to an outgoing Circuit. It can be single phase or three phases, but most of the cases it is 3-

phase and one bus consists of 3 conductors(R-Y-B).There are also various types of bus bar

arrangements depending upon their requirements. The various arrangements are mentioned

below:

Single Bus System: This type of bus arrangement is the cheapest and the simplest one. In this

scheme all the feeders and transformers are connected to only one single bus as shown below.

The major disadvantage of this kind of system is that for the maintenance of the breakers and

other equipment we have to isolate all the systems and keep it in offline. This scheme is

generally employed for the gas insulated switchyards and another disadvantage is that if you are

going for maintenance then the respective transformer or feeder should be disconnected.

Single Bus System with Bus-sectionalizer: In this type of arrangement the main bus is divided

into two different circuits by the help of a circuit breaker. The advantage of this kind of

arrangement is that if one section of the bus bar is under maintenance then the other part of the

system, which is isolated by the bus-coupler or bus-sectionalizer, is kept energized, but here also

61

if we are going for maintenance on any breaker then the respective feeder or the transformer has

to be disconnected.

Double Bus System: In this arrangement, two identical bus bars will be there, one as Main Bus-1

and the other as Main Bus-2.Here both the buses are connected through a bus coupler. The bus

coupler does two works during line charging it matches the voltage level of both the lines and

connect both the lines. Here the flexibility of the system is increased as another bus-bar acts as a

backup for the other bus-bar, but here also without any interruption we can’t go for the

maintenance.

One And A Half Breaker Scheme: This is the most advanced and widely used scheme in

modern power plants. In this type of scheme

Two feeders are connected to two different buses through their circuit breakers respectively and

these two feeders are connected by a third breaker as a tie breaker. During failure of any feeder

breaker, the third breaker comes into play and transfers power to the other feeder. This scheme

increases the availability of the feeder during maintenance or failure of the other feeder. If there

is some fault on the Bus-1 then also without tripping the units we can continue the power flow by

the help of the tie-breaker.

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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

Post type and strain type insulators are mostly used in switchyard.

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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.

Isolator: Isolators are generally no- load switches which are used to isolate the electrical lines

during maintenance. They are only operated for isolation after the circuit breaker is operated.

They are operated by means of a motor present below the isolator assembly.

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.

Wave trap: Wave trap is a resonant circuit connected in series with the HV transmission line to

prevent the transmission of high frequency signals. The communication wave is having a high

frequency of 150 KHz to 200 KHz and the electrical power has a frequency of 50 Hz. So to

avoid the communication waves to travel to the electrical equipment we are using this Wave-

trap. It creates a high reactance path for the High –frequency signal and blocks it. We are

employing these Wave-traps is due to the use of PLCC (Power Line Carrier Communication).

PLCC: PLCC stands for Power Line Carrier Communication. This technology is used in all sub-

stations for communication with other sub-stations. The information regarding the generation

and other parameters are transmitted to other sub-stations or grid by the help of this PLCC. By

the help of PLCC, we are avoiding the use of an extra wire for communication and the

information flows through the transmission lines and it is much faster than any other medium.

Circuit breaker: A circuit breaker is equipment which can make and break a circuit under

normal as well as during fault conditions. It is operated during on load condition and the arc

generated while opening the circuit is quenched by a strong di-electric medium. The most widely

used arc quenching mediums for HV Lines are Vacuum and SF6 Gas.

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Current transformer: Basically this is a step down transformer which is used for measuring

purpose as well as protection purpose. For both these purposes the CTs are designed with

different types of core. For measuring purpose, the CT saturation point is given at ankle point on

the characteristic curve between the Flux (⌀) and current (i) and for the Protection purpose the

saturation point is given at ankle point of the curve. The CTs generally have a ratio of 100:1 or

200:1 so that they will reduce the transmission line current to a very lower value suitable for

measurement and relay protection (around 5 to 4 Amps).These are connected in series with the

transmission line.

Potential transformer: Potential transformers are used to step down the line voltages up to

measurable quantity i. e 110v from any voltage level (for measurement of voltage).They are

connected in parallel with the transmission line.CTs and PTs almost look alike, but depending

upon their connections we can distinguish them.

Protective 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. Whenever there is

a fault in the bus,the relay senses it 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).The total relay circuit is given below,

(Circuit Diagram for the Relay & Circuit Breaker(CB))

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CONCLUSION

The first phase of practical training has proved to be quiet fruitful. It provided an opportunityfor

encounter with such huge machines like wagon tippler .210 MW, 210 MW & 500 MW turbines and

generators.

The architecture of the power plant the way various units are linked and the way working

of whole plant is controlled make the student realize that engineering is not just learning the structured

description and working of various machines, but the greater part is of planning proper management.

It also provides an opportunities to lean low technology used at proper place and time can

cave a lot of labour e.g. wagon Tripler (CHP).But there are few factors that require special mention.

Training is not carried out into its tree sprit. It is recommended that there should be some project specially

meant for students where presence of authorities should be ensured. There should be strict monitoring of

the performance of students and system of grading be improved on the basis of work done.

However training has proved to be quite fruitful. It has allowed an opportunity to get an

exposure of the practical implementation to theoretical fundamentals.

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REFERENCES

Power system by V.K.Mehta.

Power system design and analysis by B.R.Gupta.

Steam and gas turbines and power plant engineering by R.Yadav.

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

Power plant familirisation by DR.N.T.T.P.S(V.T.P.S).

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

THERMAL POWER PLANT PROJECT REPORT

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