Summer Project Report (Prakhar Gupta ,A2305106167)

1 | P a g e Familiarization with DCCPP (Dholpur Combined Cycle Power Project )

DCC PP

Submitted in partial fulfilment of the requirements

for the award of the degree of

Bachelor of Technology

In

Electronics & Communication Engg.

Supervisor: Submitted By:

Mr. H.P. SINGH Mr. PRAKHAR GUPTA

B.Tech ECE ,21008

Mrs. EILA SHARMA

AMITY SCHOOL OF ENGINEERING TECHNOLOGY, NOIDA

AMITY UNIVERSITY

UTTAR PRADESH

(2006-10)


CERTIFICATE

This is to cert ify that the dissertation enti t led “Familiarization with DCCPP”

is being submitted by PRAKHAR GUPTA (A2305106167) in partial fulfi l lment

for the award of the degree of Bachelor of Technology in Electronics and

Communication Engineering to the Amity University has been carried out by

them under our guidance and supervision. The results embodied in this thesis

have not been submitted to any other University or Insti tution for the award of

any other degree by them.

Date: Supervisor:

Mr. H.P. SINGH

Mrs. EILA SHARMA


ACKNOWLEDGEMENT

Setting an endeavor may not always be an easy task; obstacles are bound to come in its

way and when this happens, help is welcome and needless to say without help of those

people whom I am mentioning here, this endeavor would not have been successful.

My primary obligation is to Mr. S.B. GUPTA (Chief Engg.) who provided me the

opportunity and platform to undergo summer training in Dholpur Combined Cycle

Power Project (D.C.C.P.P.),DHOLPUR [Raj.]

During my project work many helping hands came across my way, I would like to

acknowledge my sincere and endless gratitude to them. First and foremost I express my

deep sense of gratitude to Mr. R.C. Meghwal (XEN Opr.) for his constant advice and

valuable time he has given to me for my project. They encouraged me to put forward my

best effort towards the completion of this project. I would also like to extend my special

thanks to Mr. S.B. Meena (XEn) and Mr. Gaurav(JEn) for his support at every step. I

am very much thankful to each and every member of DCCPP who helped me during the

course of training.

I am thankful from the core of my heart for the precious contribution of DG Mam, HOD

and faculty guides Mr. H.P. Singh and Mrs. Eila Sharma of ASET who provided their

best possible help. The successful completion of this training has been possible due to

sincere co-operation, guidance, inspiration, moral support and timely advice of each and

every one who devoted their utmost co-operation in this training.

PRAKHAR GUPTA


ABSTRACT

DCCPP is situated in the outskirts of Dholpur which is about 55Km.

South West of Agra. DCCPP is a Project of Rajasthan Rajya Vidhyut Utpada Nigam

Ltd.

The total estimated cost of the plant is Rs. 1155 crore. The main equipments were

supplied by M/s BHEL and it was also the main contractor for erection, testing and

commissioning of the plant. The BOP (Balance of plant) was given to M/s GEA Energy

System. The main fuel used for this plant is R-LNG (liquified natural gas) which will be

supplied by M/s GAIL. The gas required per day for both units is 1.3MM SCM at

9000Kcal.

The unique feature of this plant is that waste heat from the gas turbine is recovered by a

heat recovery steam generator to power a conventional steam turbine in a combined cycle

configuration. And also a MARK- 6 control system has been introduced for the first time

in the northern region in INDIA.


CONTENTS

Chapter Title Page No.

Chapter 1. Introduction Of The Organisation

1.1 Dholpur Combined Cycle Power

Project (DCCPP) 10

1.2 Working Principle of Combined cycle

Power Plant 11

1.2.1 Method of Transforming other

power into electrical power 12

1.3 Selection of site for the Gas Power Plant 13

1.4 Features of the Plant 15

1.5 Plant Lay Out 17

Chapter 2. Gas Turbine (GT) 18

2.1 Working of Gas Turbine (GT) 19

2.2 Theory of Operation 20

2.2.1 Gas Power Cycle 21

2.2.2 Bray ton Cycle 21

Chapter 3. Heat Recovery Steam Generator (HRSG)

3.1 HRSG 26

3.2 Application of HRSG 28


3.3 Component of HRSG 29

3.3.1 Economizer 30

3.3.2 Superheater 31

3.3.3 Evoporator 31

3.4 Salient Features of HRSG 32

3.5 Arrangement of HRSG DCCPP Plant 34

3.6 Working of HRSG 35

3.7 Specification of Boiler Drums 36

Chapter 4. Steam Turbine (ST) & Condenser

4.1 Steam Turbine (ST) 37

4.2 Advantages & Losses of ST 37

4.3 Working of ST 39

4.4 Condenser 40

4.5 Element of a Condensing Plant 41

Chapter 5. Combined Cycle Power Generation

5.1 Combined Cycle Electricity Generation 42

5.2 Advantages &Disadvantage. Of Combined

Power Plane 42

5.3 Classification of CCGPP 43

5.4 Environmental effect of Combined Cycle

Electricity Generation 43

5.5 Working of a CCPP 45

5.5.1 Power Generation 46

5.5.2 Emission Control 48

5.5.3 Transmission of Generated Power 49


5.6 Water Tanks, Natural Gas Pipeline

& Control Room 50

Chapter 6. Water Clarification cum Filtration Plant & Turbo

Generator and Extation System

6.1 Water Clarification cum Filtration Plant 53

6.1.1 Various Process that are involved in

Treatment of Water 53

6.1.2 DeMineralizing Plant (DM Plant) 54

6.1.3 Degassifire 55

6.1.4 Weak base Anion Tank 55

6.1.5 Polishinging Unit 55

6.1.6 DM Water Quality 56

6.1.7 Water Softner 56

6.1.8 Analyzer DM Plant 56

6.1.9 CW Pump House 58

6.1.10 Water Classifier 58

6.2 Turbo Generator and Excitation System 59

6.2.1 Theory behind the working of a

Turbogenerator 59

6.2.2 Main Component of Generator 60

6.2.3 Functions of excitation System 60

6.2.4 Brushless Excitation System 60


Chapter 7. 220KV Switchyard & Transformer and Maintenanc

Work

7.1 220KV Switchyard 62

7.1.1 Bus Scheme 62

7.1.2 Bus System 63

7.1.3 SF6 Gas Circuit breakers 63

7.1.4 Isolator 65

7.2 Transformers 65

7.2.1 Current and Capacitive voltage

Transformer 65

7.2.2 Lightning Arrestor and Arc Horns 65

7.2.3 Change over Schemes(Bus the Sys.) 65

7.2.4 Synchronization of the Generator

To the Grid 66

7.3 Maintenance Job to be Done on 220 KV Switchyard

7.3.1 Daily Job 67

7.3.2 Monthly Job 67

7.3.3 Quarterly Job 68

7.3.4 During annual ShutDown of Unit 70

Chapter 8. DC System & Power Line Communication

8.1 DC System 73

8.1.1 Batteries 73

8.1.2 Switchyard Building Battery bank 73

8.1.3 Battery Room 73

8.1.4 Electrolyte 74

8.1.5 Temperature Correction 74


8.1.6 Normal operation of Batteries 74

8.2 Power line carrier Communication 75

8.2.1 Earth Shielding 75

8.2.2 Working 76

RESULT AND CONCLUSION 77

BIBLIOGRAPHY


CHAPTER-1

INTRODUCTION OF THE ORGANISATION

1.1 DHOLPUR COMBINED CYCLE POWER PROJECT

DCCPP is situated in the outskirts of Dholpur which is about 55Km.

South West of Agra. Dholpur was considered an ideal location for setting up of a gas

power plant having regards to the availability of land, water, transmission network,

proximity to broad gauge railway , also well connected by roads (G.T. road passes

through this city) and being an important load center for eastern Rajasthan.

The total estimated cost of the plant is Rs. 1155 crore. The main equipments were

supplied by M/s BHEL and it was also the main contractor for erection, testing and

commissioning of the plant. The BOP (Balance of plant) was given to M/s GEA Energy

System. The main fuel used for this plant is R-LNG (liquified natural gas) which will be

supplied by M/s GAIL. The gas required per day for both units is 1.3MM SCM at

9000Kcal.

The unique feature of this plant is that waste heat from the gas turbine is recovered by a


configuration. And also a MARK- 6 control system has been introduced for the first time

in the northern region in INDIA.

A combined cycle is characteristic of a power producing engine or plant that employs

more than one thermodynamic cycle. Heat engines are only able to use a portion of the

energy their fuel generates (usually less than 50%). The remaining heat from combustion

is generally wasted. Combining two or more "cycles" such as the Brayton cycle and

Rankine cycle results in overall improved efficiency.


In a combined cycle power plant (CCPP), or combined cycle gas turbine (CCGT) plant, a

gas turbine generator generates electricity and the waste heat is used to make steam to

generate additional electricity via a steam turbine; this last step enhances the efficiency of

electricity generation. Most new gas power plants in North America and Europe are of

this type. In a thermal power plant, high-temperature heat as input to the power plant,

usually from burning of fuel, is converted to electricity as one of the outputs and low-

temperature heat as another output. . As a rule, in order to achieve high efficiency, the

temperature difference between the input and output heat levels should be as high as

possible (see Carnot efficiency). This is achieved by combining the Rankine (steam) and

Brayton (gas) thermodynamic cycles. Such an arrangement used for marine propulsion is

called Combined Gas (turbine) And Steam (turbine) (COGAS).

1.2 WORKING PRINCPLE OF COMBINED CYCLE POWER PLANT

In a steam power plant water is the working medium. High pressure steam requires

strong, bulky components. High temperatures require expensive alloys made from nickel

or while the lower temperature of a stem plan is fixed by the boiling point of water.

With these cobalt, rather than inexpensive of steel. These alloys limit practical steam

temperatures to 655 ° limits, a steam plant has a fixed upper efficiency of 35 to 40%.

For gas turbines these limitations do not apply. Gas cycle firing temperatures

above 1,200 °C are practicable. So, a combined cycle plant has a thermodynamic

cycle that operates between the gas-turbine’s high firing temperature and the waste

heat temperature near the boiling point of water.


1.2.1 Method for transforming other power in to electrical power :-

Rotating turbines attached to electrical generators produce most commercially available

electricity. Turbines may be driven by using steam. Water wind or other fluids as an

intermediate energy carrier. The most common usage is by steam in fossil fuel power

plants or nuclear power plants and by water in hydroelectric dams. Alternately turbines

can be driven directly by the combustion of natural gas.

Power plants are classified in the following categories according to the fuel used:

(a) Coal based thermal power plant

(b) Nuclear power plant

(c) Hydro electric power plant

(d) Solar power plant

(e) Wind power plant

(f) Gas power plant

Electricity From Natural gas :-

Power plant uses several methods to convert gas into electricity. One method is to burn

the gas in a boiler to produce steam, which is then used by a steam turbine to generate

electricity. A more common approach is to burn the gas in a combustion turbine to

generate electricity.

Another technology that is growing in a combustion turbine and used the hat combustion

turbine exhaust to make steam to drive a steam turbine. This technology is called

combined cycle and achieves a higher efficiency by using the same fuel source twice.


1.3 SELECTION OF SITES FOR THE GAS POWER PLANT

1. SUPPLY OF WATER

A large quantity of water is required in steam power plants. It is required:

(I) It raises the steam in the boiler.

(II) For cooling purposes such as in condensers.

(III) As a carrying medium such as in disposal of ash.

(IV) For drinking purposes.

The efficiency of direct cooled plant is about 0.5% higher than that of the plant in which

cooling towers are used. This means a saving of about Rs. 7.5 lakhs per year in fuel cot

for a 2000 MW station

2. REQUIREMENT OF LAND

The land is required not only for setting up of the plant but also for other purposes such

as staff colonies, coal storage, ash disposal etc. cost of land adds to the final cost of the

plant. So it should be available at a reasonable cost. Land should be of good bearing

capacity since it has to withstand about 7 Kg. per Sq. Cm. Moreover, land should be

reasonably level. It should not be low lying.

3. TRANSPORTATION FACILITY

The land and rail connections should be proper and capable of taking heavy and over

dimensioned loads of machines etc. To carry coal, oil etc. which are daily requirements,

we need these transport linkages.

4. LABOUR SUPPLIES

Skilled and unskilled laborers should be available rates near the site the plant.


5. ASH DISPOSAL

Ash is the main waste product of the steam power plant. Hence some suitable means for

disposal of ash should be applied. Ash can be purchased by building contractors, cement

manufacturers or it can be used for brick making near the plant site. Otherwise wasteland

should be available near the plant site for disposal of ash.

6. DISTANCE FROM THE POPULATED AREA

Since most of the modern generating stations employ pulverized fuel residues and fumes

from them are quite harmful. Therefore the site for the plant should be away from the

populated area.

7. CLIMATIC CONDITIONS

Climate conditions of a place play a significant part in economics of capital investment.


1.4 FEATURES OF THE PLANT

Two 250 MW Turbo-generator sets together with two boilers machine capacity along

with associate auxiliaries. The boilers are of natural circulation water tube single drum

pulverized fuel fired, dry bottom, balanced draft type using the direct firing system. The

steam turbines are of tandem compound operating on reheat and regenerating cycle and

condensing type. The turbo-generators. The cooling of stator is done by means of

Dimeneralized water and rotor by hydrogen. Brushless excitation system has been

provided.

TECHNICAL DATA:

1. COST OF THE PLANT Rs. 1155.15 Crore (STAGE-1)

2. DATE OF SYNCHRONIZATION:

UNIT 1 1sep2007__UNIT 2 1sep2007__UNIT 3 1 Jan 2008 __

3. CHIMNEY HEIGHT

Unit: 1, 2 220 Mt

4. WATER REQUIREMENT

400 m / hr (3 x 110m.w.)


BOILER

Type high pressure boiler drum

Capacity 780 tons/hr

Make BHEL

Steam Temperature 550 c

Steam Pressure 150 kg /cm2

GENERATOR Make Bhel

Type Tg -Hh-0250-2

Capacity 250mw

Kva 294100 Kva

Stator

Voltage 16,500 Volt

Current 10,290 Amp

Rotor

Voltage 319 Volt

Current 2386amp

Power Factor 0.85 Lag.

Speed 3000 Rpm

Frequency 50 Hz

Phase 3

Connection

Coolant Hydrogen

Gas Pressure 3 Bar

Insulation Class F


1.5 PLANT LAY OUT


CHAPTER-2

GAS TURBINE (GT)

A gas turbine extracts energy from a flow of hot gas produced by combustion of gas or

fuel oil in a stream of compressed air. It has an upstream air compressor (radial or axial

flow) mechanically coupled to a downstream turbine and a combustion chamber in

between. Gas turbine may also refer to just the turbine element.

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

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



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

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


2.1 WORKING OF GAS TURBINE

DCCPP located at Dholpur has a unique feature that the same energy source (i.e. natural

gas) is used to rotate both gas and steam turbine without wasting much of energy. As the

name implies it is a combined cycle i.e. waste heat from the gas turbine is recovered by a


configuration. Hence, the working of both gas and steam turbine is discussed here.

A gas turbine, also called a combustion turbine, is a rotary engine that extracts energy

from a flow of hot gas produced by combustion of gas in a stream of compressed air. It

has an upstream air compressor radial or axial flow mechanically coupled to a

downstream turbine and a combustion chamber in between. Gas turbine may also refer

to just the turbine element.

Energy is released when compressed air is mixed with fuel and ignited in the combustor.

The resulting gases are directed over the turbine's blades, spinning the turbine, and,

mechanically, powering the compressor. Finally, the gases are passed through a nozzle,

generating additional thrust by accelerating the hot exhaust gases by expansion back to

atmospheric pressure.

Energy is extracted in the form of shaft power, compressed air and thrust, in any

combination, and used to power electrical generators.


2.2 THEORY OF OPERATION

Gas turbines are described thermodynamically by the Brayton cycle, in which air is

compressed isentropically , combustion occurs at constant pressure, and expansion over

the turbine occurs isentropically back to the starting pressure.

In practice, friction, and turbulence cause:

a) Non-isentropic compression: for a given overall pressure ratio, the compressor

delivery temperature is higher than ideal.

b) Non-isentropic expansion: although the turbine temperature drop necessary to

drive the compressor is unaffected, the associated pressure ratio is greater, which

decreases the expansion available to provide useful work.

c) Pressure losses in the air intake, combustor and exhaust: reduces the expansion

available to provide useful work.


2.2.1 Gas Power Cycle

although any cycle may in principle be used as a heat engine or as a refrigerator and heat

pump by just reversing the direction of the process in practice there are big difference and

the study is split between power cycle and refrigeration cycle.

Many gas cycle have been proposed and several are currently used to model real heat

engines. From the academic point of view we will the brayton cycle.

2.2.2 Bray ton Cycle:-

The Brayton Cycle nomad after the American engineer George bray ton is a good model

for the operation of a gas turbines engine. Now a days used by practically all aircraft

except the smallest once by fast boast and increasingly been used for stationary power

generation.

Particularly when both power and heat are of interest the ideal bray ton cycle in the T-S

and P-V diagram and the regenerative cycle. As with all cyclic heat engines, higher

combustion temperature means greater efficiency. The limiting factor is the ability of the


steel, nickel, ceramic, or other materials that make up the engine to withstand heat and

pressure. Considerable engineering goes into keeping the turbine parts cool.

Most turbines also try to recover exhaust heat, which otherwise is wasted energy. the heat

released from the exhaust gas has been absorbed by many kms of tubing which line the

boiler. Inside these tubes is water, which takes the heat and is converted into steam at

high temperature and pressure. The type of boiler is called heat recovery steam

generation (HRSG) This steam at high temperature and pressure is sent to the turbine

where it is discharged through the nozzles on to the turbine blades.

The energy of the steam striking on the blades makes the turbine to rotate. Coupled to the

turbine is the rotor of the generator. So when the turbine rotates the rotor of the generator

turns. The rotor is housed inside a stator having heavy coils of copper bars in which

electricity is produced through the movement of magnetic field produced by the rotor.

Electricity passes from stator winding to the transformer, which increases its voltage

level so that it can be transmitted over the lines to far off places.

The steam, which has given away its energy, is changed back into water in the condenser.

Condenser contains many kms of tubing through which cold water is continuously

pumped. The steam passing over the tubes continuously loses heat and is rapidly changed

back into water. But the two waters i.e. the boiler feed water and cooling water must

never mix. Boiler water must be absolutely pure otherwise the tubing of the boiler may

get damaged due to the formation of salts inside the tubes due to the presence of different

impurities in water.

To condense large quantities of steam huge and continuous volume of water is required.

In some power stations same water has to be used again and again because there is not

enough water. So the hot water tracts are passed through the cooling towers. The cooling


towers are simply concrete shells acting as a huge chimney creating a draught of air. The

design of cooling towers is such that a draught of air is created in the upward direction.

The water is sprayed at the top of the tower. As it falls down the air flowing in the

upward direction cools it. The water is collected in a pond from where the water is

recirculated by the pumps to the condenser. Inevitably, however some of the water is

taken taken away by the draught of water in the form of vapours and it is this water with

familiar white clouds emerging from the cooling towers.

AnOther One:

Mechanically, gas turbines can be considerably less complex than internal combustion

piston engines. Simple turbines might have one moving part: the

shaft/compressor/turbine/alternator-rotor assembly (see image above), not counting the

fuel system.

As a general rule, the smaller the engine the higher the rotation rate of the shaft(s) needs

to be to maintain tip speed. Turbine blade tip speed determines the maximum pressure

that can be gained, independent of the size of the engine.

Thermal power station burn fuels and use the resultant steam to drive the turbo generator.

The object is to convert heat into mechanical energy in the turbine and to convert

mechanical energy into electrical energy by rotating magnets inside a set of magnets. The

coal brought to the station by means of trains travel from the coal handling plant by

conveyor belts to the coal bunkers. From where it is fed to pulverizing mills which grind

it to a fine powder. Finely powdered coal mixed with preheated air is blown into the

boiler by primary air fan where it burns more like a gas than as a solid with additional

amount of air called the secondary air supplied by the secondary draft fan.


As the coal has been ground finely the resultant ash is fine powder. Some of its contents

bind together to form lumps which fall in ash pits at the bottom of the furnace. The ash

mixed with water is then taken to the pits for subsequent disposal. The electrodes charged

by high voltage electricity in the electrostatic precipitator trap most of the ash. The dust is

then conveyed by water to the disposal area or to the bunkers while the cleaned flue gases

pass on through the ID fan to discharge through the chimney. Meanwhile the heat

released from the burning of coal has been absorbed by many kms of tubing which line

the boiler. Inside these tubes is water, which takes the heat and is converted into steam at

high temperature and pressure.

This steam at high temperature and pressure is sent to the turbine where it is discharged

through the nozzles on to the turbine blades. The energy of the steam striking on the

blades makes the turbine to rotate. Coupled to the turbine is the rotor of the generator. So

when the turbine rotates the rotor of the generator turns. The rotor is housed inside a

stator having heavy coils of copper bars in which electricity is produced through the

movement of magnetic field produced by the rotor. Electricity passes from stator winding

to the transformer, which increases its voltage level so that it can be transmitted over the

lines to far off places.

The steam, which has given away its energy, is changed back into water in the condenser.

Condenser contains many kms of tubing through which cold water is continuously

pumped. The steam passing over the tubes continuously loses heat and is rapidly changed

back into water. But the two waters i.e. the boiler feed water and cooling water must

never mix. Boiler water must be absolutely pure otherwise the tubing of the boiler may

get damaged due to the formation of salts inside the tubes due to the presence of different

impurities in water.


To condense large quantities of steam huge and continuous volume of water is required.

In some power stations same water has to be used again and again because there is not

enough water. So the hot water tracts are passed through the cooling towers. The cooling

towers are simply concrete shells acting as a huge chimney creating a draught of air. The

design of cooling towers is such that a draught of air is created in the upward direction.

The water is sprayed at the top of the tower. As it falls down the air flowing in the

upward direction cools it. The water is collected in a pond from where the water is re-

circulated by the pumps to the condenser. Inevitably, however some of the water is taken

away by the draught of water in the form of vapours and it is this water with familiar

white clouds emerging from the cooling towers.


CHAPTER-3

HEAT RECOVARY STEAM GENERATOR (HRSG)

3.1 HRSG

A heat recovery steam generator or HRSG is a heat exchanger that recovers heat from a

hot gas stream. It produces steam that can be used in a process or used to drive a steam

turbine. A common application for a HRSG is in a combined-cycle power station, where

hot exhaust from a gas turbine is fed to an HRSG to generate steam which in turn drives a

steam turbine. This combination produces electricity more efficiently than either the gas

turbine or steam turbine alone. The HRSG is also an important component in

cogeneration plants. Cogeneration plants typically have a higher overall efficiency in

comparison to a combined cycle plant. This is due to the loss of energy associated with

HRSGs consist of three major components. They are the Evaporator, Superheater, and

Economizer. The different components are put together to meet the operating requirements of the

unit. See Modular HRSG GA.


Modular HRSGs normally consist of three sections: an LP (low pressure) section, a

reheat/IP (intermediate pressure) section, and a HP (high pressure) section. Each section

has a steam drum and an evaporator section where water is converted to steam. This

steam then passes through superheaters to raise the temperature and pressure past the

saturation point.

Packaged HRSGs are designed to be shipped as a fully assembled unit from the factory.

They can be used in waste heat or turbine (usually under 20MW) applications. The

packagaged HRSG can have a water cooled furnace which allows for higher

supplemental firing and better overall efficiency.


Some HRSGs include supplemental, or duct, firing. These additional burners provide

additional energy to the HRSG, which produces more steam and hence increases the

output of the steam turbine. Generally, duct firing provides electrical output at lower

capital cost. It is therefore often utilized for peaking.

HRSGs can also have diverter valves to regulate in the inlet flow into the HRSG. This

allows the gas turbine to continue to operate when there is no steam demand or if the

HRSG needs to be taken offline.

Emissions controls may also be located in the HRSG. Some may contain a Selective

Catalytic Reduction system to reduce nitrogen oxides (a large contributor to the

formation of smog and acid rain) and/or a catalyst to remove carbon monoxide. The

inclusion of an SCR dramatically affects the layout of the HRSG. NOx catalyst performs

best in temperatures between 650°F and 750°F. This usually means that the evaporator

section of the HRSG will have to be split and the SCR placed in between the two

sections. Some low temperature NOx catalysts have recently come to market that allows

for the SCR to be placed between the Evaporator and Economizer sections (350°F-

500°F).

3.2 APPLICATIONS OF HRSG

Heat recovery can be used extensively in energy projects.

In the energy-rich Persian Gulf region, the steam from the HRSG is used

for desalination plants.

Universities are ideal candidates for HRSG applications. They can use a gas

turbine to produce high reliability electricity for campus use. The HRSG can recover

the heat from the gas turbine to produce steam/hot water for district heating or

cooling.

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

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

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


3.3 COMPONENT & ARRANGEMENT OF HRSG

There are two boiler drums in HRSG-

1.High pressure drum

2.Low pressure drum

There are deviation in boiler drums . Steam accumulated in upper part of drum water in

the lower part of the drum water is drawn out by a pipe at the bottom of the drum

If there are excess pressure and temperature. Then to remove these there are two

controlling arrangements

1.Pressure controlling arrangement.-pressure safety valves like pressure cooker

whistle loaded there and design to release excess pressure.

2.temprature controlling arrangement-a “D”shape pipe is there for control the

excess temp. If temp. exceed demineralized water is sprayed in it. And the temp.

lowered

There are two HRSG plant for two gas turbine.

The combined steam of HRSG-1& HRSG-2 produce the power of 110MW.

In a boiler drum there are riser pipes. from which steam comes into the drum.

HP drum is bigger then LP drum

There are three main components of HRSG

1.Economisers

2.superheaters

3.evoporator


3.3.1 Economiser

The greatest item of heat loss in a boiler plant is that pf the heat is carried away in the

flue gases of the chimney stack. some of this heat may be recovered and sent back into

the boiler in the feed water by an economizer a saving of 10 percent.

The advantage of economizer are

1. increase the efficiency of boiler plant

2. reduce the range of temp.b/w different parts of boiler and hence reduces the stress

due to unequal expansion

3. more rapid evaporation and hence quicker circulation of water making the heating

surface increase the efficiency of boiler plant

4. reduce the range of temp.b/w different parts of boiler and hence reduces the stress

due to unequal expansion

5. more rapid evaporation and hence quicker circulation of water making the heating

more effective

Disadvantage of economiser

1. there is a loss of draught for the flue gases and natural draught is un sufficient. the

plant has to provided with an artificial draught equipment


3.3.2 Superheater

A superheater is a device used to convert saturated steam into dry steam used for power

generation or processes. There are three types of superheaters namely: radiant,

convection, and separately fired. A superheater can vary in size from a few tens of feet to

several hundred feet (a few meters or some hundred meters)

It is surface heat exchanger in which the heat of the combustion product is utilized first

to dry wet steam and then to raise the temp. in super heater there is no change of pressure

of steam but its volume increased and temp is raised.

3.3.3 Evoporator

Within a downstream processing system, several stages are used to further isolate and

purify the desired product. The overall structure of the process includes pre-treatment,

solid-liquid separation, concentration, and purification and formulation. Evaporation falls

into the concentration stage of downstream processing and is widely used to concentrate

foods, chemicals, and salvage solvents. The goal of evaporation is to vaporize most of the

water from a solution containing a desired product. After initial pre-treatment and

separation, a solution often contains over 85% water. This is not suitable for industry

usage because of the cost associated with processing such a large quantity of solution,

such as the need for larger equipment

Evoporator-in this phase change is done .in this water change into steam

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

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

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

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

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

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


3.4 SALIENT FEATURES OF HRSG

Horizontal Natural Circulation Design.

Steam generation at multiple pressure levels with or without reheaters.

Modular construction with spiral finned tubes for compactness.

Fully drainable heat transfer section

Short installation time.

Ease of operation.

Supplementary Fuel firing system to meet specific customer requirements.

o -In duct firing/Furnace firing.

o Multiple Fuel firing (Oil/Gas).

Low NOx and CO emission.

o Stand by fresh air firing with FD fan for uninterrupted steam supply ( FD

Fan mode ).

Unfired boiler.

Exhaust gases are used to generate steam.

500 c lower portion.

High pressure circuit two.

6H bar upper portin economizer.

Low temperature portion.

6 bar 202 c (ragging)

Discharge pressure 1H bar steam

Water tube boiler.

Forced circulation boiler.

Vertical boiler.

At 100 c leaver boiler.

Deareater feed storage tank


Circuit feed regulating

Economizer station controls

Evaporator flow

Super heater H.P. turbine and L.P. turbine

Twin cyclender turbine.

Tendon compound turbine.

HP STEAM (RATED PARAMETERS)

• PRESSURE : 78.2 Kg/Cm2.

• TEMPERATURE : 514+/- 5 Deg. C

• FLOW : 187.1 TPH.

LP STEAM (RATED PARAMETERS)

• PRESSURE : 5.0 Kg/Cm2.

• TEMPERATURE : 200 Deg. C

• FLOW : 39.8 TPH.


3.5 ARRANGEMENT OF HRSG DCCPP PLANT


3.6 WORKING OF HRSG

In this the water used in steam generation is de mineralized water .because steam of DM

water not contains any particles and minerals. If these substances present in steam it may

be harmful for turbine blades.

From a water reservoir water is supplied in water clarifier .then supplied in DM plant in

which water is undergoes too many chemical reactions with diff. chemicals to remove its

impurities & minerals after which is supply to the plant.

First of all dm water comes in economizer so that increase the temp. of water. in this the

hot flue gases passes over exterior of tubes. heating of feed water by 1deg.c permits

reducing the temp. of flue gases by 2to3 deg. By this efficiency of boiler is increased.

After this water is supplied to boiler drum then evaporator. In this water is converted into

steam. this steam is wet steam. then this steam passes through superheaters to raise the

timpani pressure past the saturation point. by this dry steam is getting after this steam is

supplied to boiler drum and then steam turbine.

Wet steam may be harmful to turbine blades. So superheated steam is used to turbine.

There are so many modules of components of HRSG. These are alloy steal pipes

surrounded by small fins in which water flow for heating purpose .and these fins are used

for heat transfer and cooling of pipes,

These modules are a type of heat exchanger where heat exchange takes place b/w DM

water & exhaust of turbine.

Boiler drums are made by mild steel . because of its ductility.


3.7 SPECIFICATION’S OF BOILER DRUMS

1. HP DRUM :

Design pressure 105kg/ cm2

Working pressure 78.2kg/ cm2.

Hydraulic pressure 157.5kg/ cm2

Water temperature ambient

Holding time 10 min.

HP steam 79.8kg/cm2

Steam temp 490°c

2. LP DRUM:

Design pressure 12kg/ cm2.

Working pressure 05 kg/ cm2

Hydraulic pressure 18kg/ cm2

Water temp. ambient

Holding time 10 min.

Steam temp. 220°c

3. CHIMENY EXHAUST:

Maximum temperature 90°c

Working temperature 65-70°c


CHAPTER-4

STEAM TURBINE (ST) & CONDESER

4.1 STEAM TURBINE

In a steam turbine steam is passed through nozzles or fixed blades where the heat drops

takes place increasing the velocity of steam. the high velocity steam impinges on the

curved vanes which causes the directions of the steam to be changed. Due to this change

of momentum motive force is exerted on the moving blades and power is obtained.

4.2 ADVANTAGE OF STEAM TURBINE

1. the thermodynamic efficiency of steam turbine is higher than that of steam engine

because these work on Rankine cycle whereas steam engine works on modified

Rankine cycle. A steam turbine can thus take advantage of expansion up to the

lowest pressre. the lowest exhaust pressure of steam turbine is as low as 2.5cm

hg(.035 bar)whereas in steam engines it is 15 to 20cm of hg(.2to.3bar)

2. the mechanism is simple as inter mediate links like piston, piston rods, croos

head, etc, are absent.

3. there is no initial condensation as the parts are subjected to constant temp. and at

constant loads.

4. power is generated uniform rate ,hence no fly wheel is necessary.


5. no internal lubricant is necessary, which reduce the cost of lubrication and

supplies a purer feed to the boiler.

6. due to absence of reciprocating parts, perfect balance is possible which avoids

heavy foundations.

7. steam turbine can carry considerable overloads with only a slight reduction in

efficiency.

8. the thermal efficiency of steam turbines plants is 35to40%, whereas for steam

engine it is 15to 20 %.

LOSES IN STEAM TURBINE

1. Loss in the exit velocity of steam: The loss in the exit velocity of the steams due

to blade efficiency not being 100percent.this is because of the obliquity of

nozzles. if the nozzle angle is zero, blade efficiency would be 100 percent.

2. Loss due to friction and turbulence: Friction occurs in nozzles and blades and b/w

steam and rotating disc. also due to centrifugal action steam is thrown radially

towards the casing and dragged along the surface by the moving blades. these

losses are called the disc friction and wind edge losses.

3. Loss due to leakage: In impulse turbine leakage occurs b/w the shaft and the

stationary diaphragms carrying nozzles. in the reactions turbine the leakage is at

the blade tips.


4. Losses due to mechanical friction to the bearing , etc. this loss is less then 1 %

and it decreases with the size of the plant.

5. Losses due to radiation is negligible.

6. Governer losses: it is due to throttling. This may in order to 5to10%.

7. Exhaust losses: the steam leaves the turbine with a finite. Absolute velocity which

is partially or wholly lost.

In this plant steam turbine produces 110MW electricity, running by combined steam of

HRSG. so in this plant cost of coal handling and ash handling is negligible.

4.3 WORKING OF STEAM TURBINE

The steam turbine is a Siemens Westinghouse KN Turbine Generator, capable of

producing up to 240 MW. It is located on top of the condenser, across from the

cooling tower.

Steam enters the turbine with temperatures as high as 1000 degrees Fahrenheit

and pressure as strong as 2,200 pounds per square inch. The pressure of the steam

is used to spin turbine blades that are attached to a rotor and a generator,

producing additional electricity, about 100 megawatts per HRSG unit.

After the steam is spent in the turbine process, the residual steam leaves the

turbine at low pressure and low heat, about 100 degrees. This exhaust steam

passes into a condenser, to be turned back into water.


By using this “combined-cycle” process, two gas turbines and one steam turbine,

we can produce a total of about 110 megawatts of electricity.

4.4 CONDESER

The purpose of the condenser is to turn low energy steam back into pure water for

use in the Heat Recovery Steam Generator

A condenser makes it possible to remove exhaust economically at a pressure less

then that of atmosphere . thus by use of an condenser in a steam plant low exhaust

pressure can be used and large heat drop per kg of steam utilized increasing both

the efficiency and power output of the plant.

ADVANTAGE:

Hot feed water at 40°c to 50°c is available for returning to the boiler.

Air and non condensable gases , which have corrosive action, are removed.

Recovery of condensate reduce the make up water that must be added to the

system.

Where the feed water available is not pure , recovery of condensate reduce the

capital and running cost of the water softening plant.

In a condenser , absolute vacuum is neither possible nor economical to maintain . beside

enormous increases in the condenser size a higher vacuum result in lower temperature of

the condensate returned to the boiler and increase in the rate of flow of cooling water and

consequently the power required to derive the circulating pumps.


4.5 ELEMENT OF A CONDENSING PLANT

1. The condenser where steam is condensed.

2. The condensate pump for extracting water for the condenser to the hot well.

3. The hot well for collecting the condensate.

4. The air ejector or dry air pump for removing the non condensable gases from the

condenser.

5. The circulating water pump for circulating the cooling water.

6. The cooling tower if same circulating water is to be used again and again.

sometime the term hot well is applied to the collection space at the bottom of condenser

and the hot well is termed “surge tank”


CHAPTER-5

COMBINED CYCLE POWER GENERATION

5.1 COMBINED CYCLE ELECTRICITY GENERATION

Growth in gas fueled combined cycle system will take place, Because of the attractive

economic environmental and operating characteristics of this natural gas system .

Combined cycle gas turbine plants generate electricity more. Efficiently than

conventional fossil to percent compares with 30 to 50 percent for typical now biological

units.

5.2 Advantage of Combined Cycle Gas Power Plant

High Thermal Efficiency

Low water Requirement

Environmental friendliness

Fast start-up

Low Gestation period

Low Installation Cost

Disadvantage of Combined Cycle Gas Power Plant

Low thermal Efficiency in Open cycle

Higher Cost of Generation

Higher Maintenance Cost


5.3 Classification of Combined Cycle Gas Power Plant

SIZE PLANT CAPACITY GT CAPACITY

SMALL UP-TO 100 MW 30-40 MW

MEDIUM 150-400 MW 60-120 MW

LARGE > 400 MW > 120 MW

5.4 Environmental effects of combined cycle electricity generation

(a). Natural-gas fueled combined cycle units are environmentally performable to

conventional coal system the gas combined cycle unit produces none of the solid waste

associated with coal units less than 1 percent of the sulfur dioxide and particulate matter

and about 85 percent less nitrogen oxide produces by a similarity sized new coal unit

equipped with pollution control equipments.

(b). Cogeneration System :- Cogeneration is use of a primary energy like natural gas to

sequentially produce heat and electricity. The concept is based on the recover and use of

waste heat produced daring the generation of electricity. In most electric utility power

plants. This waste heat is lost resulting in substantially lower operating efficiencies than

with cogeneration.


A variety of natural gas cogeneration technologies are currently being used. Including

small prepackaged units that incorporate all the necessary components for a cogeneration

system as well as high efficiency industrial gas turbines. These natural gas cogeneration

system are available in sizes ranging from as small as 202 kw to as larges as several

hundred mega watts.

(c.) Air Emissions :- The average emissions rates in the united states from natural gas

fired generation are 1135 ibd/meh of carbon dioxide 0.1 ibs/mwh of sulfer dioxide and

1.7 ibs/mwh of nitrogen oxide compared to the average air emissions from coal fired

generation natural gas produces as much carbon dioxide less than a third as much

nitrogen dioxide at the power plant in addition the process of extraction treatment and

transport of the natural gas to the power plant generators additional emissions.

(d) Design Principle :- in a gas turbine set composed primarily of a compressor burner

and the gas turbine proper. The input temperature to the gas turbine is relatively high but

the output temp of the fuel gas temperature is sufficient for production of steam in the

second steam cycle with live steam temperature in the range of steam cycle depends on

the ambient temperature and the methods of waste heat disposal either by direct cooling

by lake river or sea water or using cooling towers.

(e) Efficiency of CCGT Plants :- The thurmel efficiency of a combined cycle power

plant is normally in termsof the net power output of the plant as a percentage fo the lower

heating value or net calorific value of the fuel. In the case of generating only etc. criticity

power plant efficiencies of up to 59% can be achieved in the case of combined heat and

power generation the efficiency can increase to about 85%.


5.5 WORKING OF A COMBINED CYCLE POWER PLANT

DCCPP located at Dholpur has an unique feature that the same energy source (i.e. natural

gas) is used to rotate both gas and steam turbine without wasting much of energy. As the

name implies it is a combined cycle i.e. waste heat from the gas turbine is recovered by a


configuration.


5.5.1 Power Generation:

1) Air Inlet

The amount of air needed for combustion is 800,000 cubic feet per minute. This

air is drawn though the large air inlet section where it is cleaned, cooled and

controlled, in order to reduce noise.

2) Two Siemens Westinghouse 501FD Turbine-Generators:

The air then enters the gas turbine where it is compressed, mixed with natural gas

and ignited, which causes it to expand. The pressure created from the expansion

spins the turbine blades, which are attached to a shaft and a generator, creating

electricity.

Each gas turbine produces 185 megawatts (MW) of electricity.

The blades are attached to a rotor, which spins the generator, and makes

electricity. Think of a generator as a huge spinning magnet inside a coil of wire.

As the magnet spins, electricity is created in the wire loops.

3) Heat Recovery Steam Generator (HRSG)

The hot exhaust gas exits the turbine at about 1100 degrees Fahrenheit and then

passes through the Nooter Erickson, Heat Recovery Steam Generator (HRSG).

In the HRSG, there are 18 layers of 100-foot tall tube bundles, filled with high

purity water. The hot exhaust gas coming from the turbines passes through these

tube bundles, which act like a radiator, boiling the water inside the tubes, and

turning that water into steam. The gas then exits the power plant through the


exhaust stack at a much cooler 180 degrees, after having given up most of its heat

to the steam process.

About 1 million pounds of steam per hour is generated in this way and sent over

to the steam turbine through overhead piping.

4) Steam Turbine

The steam turbine is a Siemens Westinghouse KN Turbine Generator, capable of

producing up to 240 MW. It is located on top of the condenser, across from the

cooling tower.

Steam enters the turbine with temperatures as high as 1000 degrees Fahrenheit

and pressure as strong as 2,200 pounds per square inch. The pressure of the steam

is used to spin turbine blades that are attached to a rotor and a generator,

producing additional electricity, about 100 megawatts per HRSG unit.

After the steam is spent in the turbine process, the residual steam leaves the

turbine at low pressure and low heat, about 100 degrees. This exhaust steam

passes into a condenser, to be turned back into water.

By using this “combined-cycle” process, two gas turbines and one steam turbine,

we can produce a total of about 110 megawatts of electricity.


5.5.2 Emissions Control

1) Selective Catalytic Reduction (SCR)

To control the emissions in the exhaust gas so that it remains within permitted

levels as it enters the atmosphere, the exhaust gas passes though two catalysts

located in the HRSG.

One catalyst controls Carbon Monoxide (CO) emissions and the other catalyst

controls Oxides of Nitrogen, (NOx) emissions.

2) Aqueous Ammonia

In addition to the SCR, Aqueous Ammonia (a mixture of 22% ammonia and 78%

water) is injected into system to even further reduce levels of NOx.

3) Best Available Control Technology (BACT)

Our annual average concentration of NOx is only 2 parts per million, which is

considered the “best available control technology” or BACT by the Air Board.

As exhaust gas passes out of the exhaust stack, it is continuously sampled and

analyzed, assuring that permit limits are being met.

With this kind of clean, modern technology, the exhaust stack is only 145 feet

high, compared to 500 feet, the height required by older power plants that use less

efficient emission technology.


Environmental and health organizations recognize this technology as a benefit to

the community. The local chapters of the American Lung Association and Sierra

Club both support the Metcalf Energy Center.

5.5.3 Transmission of Generated Power onto the Grid

1) Transformers

The Gas Turbine and Steam Turbine generators produce power at 13,000 volts.

The transformers take the generated 13,000 volts and “transform” them to

230,000 volts, which is the required voltage needed for transmission to the nearby

tower that sends power to the substation.

A small amount of generation is directed to “Auxiliary transformers” which

“transform” the generated voltage to a lower voltage, so it may be used by the

plant to power our own pumps, fans, and motors. The Metcalf Energy Center

requires 12 – 15 megawatts to operate.

2) Switchyard

From each transformer, the power passes underground into our switchyard. The power from all

of the generators comes together there, where it is measured, metered and directed onto the

grid.

The proximity of the site to a large, existing PG&E substation makes it a good

place to build a power plant and the nearest transmission tower is only about 200

feet away.


3) Condenser and Cooling Tower

The purpose of the condenser is to turn low energy steam back into pure water for

use in the Heat Recovery Steam Generator.

The purpose of the cooling tower is to cool the circulating water that passes

through the condenser. It consists of ten cells with large fans on top, inside the

cone-like stacks, and a basin of water underneath.

We process and treat the Title 22 recycled water after receiving it from the City,

before using it in our cooling tower. The cool basin water absorbs all of the heat

from the residual steam after being exhausted from the steam turbine and it is then

piped back to the top of the cooling tower.

As the cool water drops into the basin, hot wet air goes out of the stacks.

Normally, hot moist air mixes with cooler dry air, and typically a water vapor

plume can be formed, one that may travel hundreds of feet in the air and be seen

from miles away. The California Energy Commission considered this visually

undesirable in this community so we added a “Plume-Abatement” feature, louvers

along the topsides of the tower that control the air flow.

The cooling tower evaporates about three-fourths of the processed, recycled

water, then we send about one-fourth of it back through the sewer lines for re-

treatment by the City.

The Metcalf Energy Center purchases 3 to 4 million gallons per day of recycled

water from the City of San Jose. Evaporation of this water assists the City in

adhering to their flow cap limits and helps to protect the sensitive saltwater marsh

habitat of the San Francisco Bay environment from receiving too much fresh,

recycled water.


5.6 Water Tanks, Natural Gas Pipeline, Control Room

1) Water Tanks

The largest tank is the Service Water tank. It contains 470,000 gallons of water to

be used for drinking, fire fighting and for the high purity water train. The water

from the service water tank is pumped to the water treatment building where it

then passes through a reverse osmosis unit, a membrane decarbonater, and mixed

resin bed demineralizers to produce up to 400 gallons per minute of ultra pure

water.

The pure water is then stored in the smaller 365,000-gallon tank until it is turned

into steam for making electricity.

2) Natural Gas

Natural gas fuels the combustion turbines. Each turbine can consume up to 2,000

MMBTU per hour.

The fuel comes from the major high pressure natural gas pipeline that runs along

the east side of Highway 101, less than 1 mile to the east of our site.

During construction, “Horizontal Directional Drilling” was utilized with careful

coordination with many local authorities. The pipeline was built 60 feet

underground and passed under highways, creek, train tracks, and environmentally

sensitive areas.

The pipeline enters the site just behind the water tanks, where equipment

regulates and measures the natural gas composition, flow and pressure.

Gas compressors pump the natural gas though the facilities’ fuel gas system

where it is delivered to the gas turbine and the HRSG duct burners at the proper

temperature, pressure and purity.


3) Control Room

From the control room, the plant operators monitor and operate the facility, via

the plant’s “Distributed Control System”, with the click of a mouse, viewing

graphic representations of all MEC systems on various screens.

The system gives operators both audible and visual signals to keep them informed

of plant conditions at all times and to determine when preventative maintenance is

required.

CONTROL ROOM

WATER TANK


CHAPTER-6

WATER CLARIFICATOIN CUM FILTRATION PLANT &

TURBO-GENERATOR AND EXCITATION SYSTEM

6.1 WATER CLARIFICATOIN CUM FILTRATION PLANT

The source of water to the power station is from across river Chambal .the total water

requirement for the capacity 330 MW is estimated at 850 cusses . the river water contains

different impurities-

Suspended Impurities – Removed by Al, Cl2 , Co(OH) 2 where alum is used to

coagulate.

Colloidal Impurities – Removed by alum and filteration of water

Soluble impurities-

Biological Impurities-

6.1.1 VARIOUS PROCESS THAT ARE INVOLVED IN

TREATMENT OF WATER:

1. Coagulation with chemical addition in slash mixture.

2. Filteration in rapid gravity filter

3. Chlorinisation for removal of organic matter.

4. Clarification in clariflocculator.

The coagulated particles are removed in form of sledge. filteration plant consisting of

rapid gravity filters supplies filtered water for dm plant. Raw water is pumped by means

of pumps located in CW pump house and enters the clariflocculator through a raw water


inlet channel and flash mixer. Alum, lime and chlorine solution are dosed in raw water

channel and mixed with it. A tap of is taken from the clarified water channel to five rapid

sand filter of capacity(60 m3/hr each). Now it is purified to dm water requirement of all

the 4 units. M?S Geo Miller & Co. Pvt. Ltd. Supplies equipment for this plant

6.1.2 DEMINERALIZING PLANT

Purified water coming from classifier is sent to dm plant through pumps. Impure water

causes sludge and scale formation inside the boiler hence the need of dematerialized

water arises. The water in dm plant undergoes through various steps.

1. ACTIVATED CARBO FILTER (ACF):

Tank in which alternate layers of CO2 and sand are placed. Ac waterfalls from top,

suspend particles (not removed by classifier) are filter. Also the excess of chlorine is

removed from here water goes into SAC tank.

2. STRONG ACID CATION TANK (SAC TANK):

This tank has 2 layers of resins which is used to remove cautions or positive ions viz.

Ca2+

, Mg2+

, Fe2+

, K+.

(R) – H + CaSO4 -----> R- Ca + H2SO4/H2CO3/HCO3/HCL

Resin is a polymer of PVC. It contains polystyrene and polyvinylchloride. From SAC

tank, water is pumped to degassifire.


6.1.3 DEGASSIFIRE

In it oxygen is removed from the water to avoid corrosion at later stages water falls from

the top and air at high pressure is passed as a jet through it in a partially evacuated

chamber like vessel. This take away the oxygen from water. Now the water is pumped to

WVA tank. It improves pH of the water.

6.1.4 WEAK BASE ANION TANK

In this tank, the negative anions are removed from minerals by the reaction

(R) – OH + H2SO4 -----> H-OH + RSO4

The R SO4 part is filtered through resin layer used. The filtered from above process is free

from trivalent ions and most of the bivalent ions. Bivalent ions left and the monovalent

ions are removed in SBA tank.

6.1.5 POLISHINGING UNIT

It consists of tank which have mixed bed (layers, which have the ability remove positive

as well as negative ions). The water emerging out of this unit is dm water.


6.1.6 DM WATER QUALITY

pH between 6 to 8

Iron, free CO2 not traceable

Conductivity less than 0.3 micro siemons / cm at 20°c

Total silica less than .020 PPM

Total electrolyte less than 0.1 PPM

After both the anion and cation exchanger get exhausted, anion exchanger is then

treated with NaOH and cation exchanger is then treated with H2SO4

6.1.7 WATER SOFTNER

water softening plant also known as zeolite water softening plant has been provided to

meet bearing cooling water and make up water loss.

6.1.8 ANALYZER DM PLANT

Analyzer is an instrument, which is used for the monitor the situation of water at various

points . analyzer is an instrument because it -

1. Gives an inside picture of the process and avoid shut down of machine.

2. it prevent the change in boiler , tubes , turbine blades and generator.

3. SiO2, Na , dissolved O2 ,NH3 Are monitored when the quantity is exceeding by a

limit.


THE MONITORING POINTS ARE

1. HPH to economizer - O2

2. at boiler - SiO2 , Cl

3. Condenser to extraction pump

4. Water treatment plant to condenser – (Na , SiO2)

SPECIFICATIONS OF CW PUMPS

Power 1700KW

Rated capacity 16000m3/hr each

Rated speed 497rpm

No load current 81 amp

Full load current 193.7 amp

Direction of rotation Clock wise from top

Voltage 6.6KV


6.1.9 CW PUMP HOUSE

The cooling water for condenser should be drawn from intake sump through CW pump.

At the entrance of each CW pump, there exists a seal pit from intake sump, traveling

water screens are provided for efficient screening of cooling water and preventing devris

from going into cooling system

The hot water from each unit condenser is connected to seal pit. The CW pipe work is

provided with necessary butterfly valves and rubber expansion joints at require points.

6.1.10 WATER CLARIFIER

It is provide for removing turbidity. Suspended and colloidal solids from raw water by

chemical treatment. All pipe works, storage tanks chemical dosing equipments are

designed to meet the requirements. The raw from chambal river will be taken into the

outdoor CW sumps through CW intake channel. To collect water in this sump will be

pumped to clarification and filteration plants. Through vertical turbine raw water pumps

located in the pump house. The raw water pumps located in the pump house.


6.2 TURBO-GENERATOR AND EXCITATION SYSTEM

An Turbogenerator is an electromechanical device that converts mechanical

energy to electrical energy, using a rotating magnetic field

6.2.1 THEORY BEHIND THE WORKING OF A TURBOGENERATOR

An Turbogenerator generally includes a rotor that rotates within a stator core to

convert mechanical energy into electrical energy.

A frame-supported stator core provides a high permeability path for magnetic flux

and a rotor assembly positioned to rotate continuously within the stator core so as

to induce electrical current.

The resulting current is carried by high-current conductors through and out from

the power generator, to connectors that provide the current to a plant bus for

power distribution.


6.2.2 Main Components of Generator

• Stator

– Stator Frame (Fabrication & Machining)

• Core Assembly

– Stator Core, Core Suspension Arrangement

• End Shield

• Stator Winding Assembly

– Stator Winding , Winding Assembly, Connecting Bus bar, Terminal

Bushing

• Rotor

– Rotor Shaft, Rotor Wedges, Rotor Coils, Wound Rotor, Rotor Assembly

• Completing Assembly

– Bearing Assembly, Shaft Seal Assembly, Oil Catchers, Insert Cover etc

• Exciter

• Auxiliary Systems

6.2.3 FUNCTIONS OF EXCITATION SYSTEM

GENERATION OF AIR GAP FLUX TO GET ELECTRICAL OUTPUT.

TO GENERATE SYNCHRONISING TORQUE TO KEEP THE MACHINE IN

SYNCHRONISM.

TO GENERATE REACTIVE POWER (MVAR)

FAST RESPONSE TO SYSTEM DISTURBANCES.

CAPABILITY TO GENERATE FIELD FORCING CONDITION FOR

PROMPT CLEARANCE OF FAULTS.


6.2.4 BRUSHLESS EXCITATION SYSTEM

CONTACT LESS SYSTEM

ELIMINATES ALL PROBLEM RELATED TO TRANSFER OF POWER

BETWEEN

STATIONARY AND ROTATING ELEMENTS

COMPLETELY ELIMINATES BRUSHGEAR ,

SLIPRINGS, FIELD BREAKER .

ELIMINATES THE HAZARD OF CHANGING

BRUSHES ON LOAD

BRUSH LOSSES ARE ELIMINATED

RELIABILITY IS BETTER

IDEALLY SUITED FOR LARGE SETS


CHAPTER-7

220KV SWITCH YARD & TRANSFORMER AND

MAINTENANCE WORK

7.1 220KV SWITCH YARD

7.1.1 BUS SCHEME

Main Function Of The Stations Is To Receive The Energy And Transmit It At The

Required Voltage Level With The Facility Of Switching.

At STPS Following Are The Bays:-

1 Bus Coupler - 1

2 Sog -1

3 Sog -2

4 Generator Transformer -1

5 Ratangarh -1

6 Station Transformer -1

7 Bus Sectionalizer

8 Ratangarh - 2

9 Bus Tie

10 Generator Transformer-2

11 Interlinking-1

12 Station Transformer-2

13 Interlinking -2





7.1.2 Bus System

There Are Mainly Three Buses

1 Main Bus-1

2 Main Bus-2

3 Transfer Bus

Material of bus bar- Tarantull Al conductor with a capacity of 2400 amperes. Bus

coupler-1 can be used as GT breaker for unit 1, 2 and 3. Only one bus coupler can be

used as a GT breaker at a time.

7.1.3 SF6 GAS CIRCUIT BREAKERS:

In this type of breaker quenching of arc is done by SF6 gas. The opening and closing of

the circuit breaker is done by air.

TYPE DESIGNATION:-

E : S F 6 Gas Insulation

L : Generation

F : Out Door Design

SL : Breaker Construction

4 : Code BIL Rated Voltage 4 - 245 / 460 / 1050 kv

1 : No. of chamber


The high voltage circuit breaker type ELF SL 4-1 comprises 3 breaker poles , a common

control cubicle and a pneumatic unit ( compressed air plant)

A breaker pole consists of :-

- SUPPORT (FRAME) - 40000

- POLE COLUMN - 41309 N

- PNEUMATIC ACTUATOR ( PKA) - 90200

The actuator is operated with compressed air.

A pneumatic unit ( 97200), an air receiver and a unit compressor is installed to supply

the compressed air. the compressed air stored in the air receiver is distributor to the three

actuator via pipe line.

The common control cubicle ( 96000), which is installed separately contains all control

devices and most of the monitoring instrumentation with the exception of the density

monitor 98005 mounted on the middle breaker pole. the pressure switches are installed in

the control cubicle. all three poles columns are filled with insulating gas and

interconnected by means of pipe lines. the gas is monitored by a density monitor 98005 (

temp. compensated pressure monitor )

If all the poles of the circuit breaker do not close simultaneously then the pole

discrepancy relay will operate and trip the breaker. Also at the time of tripping, if all the

breake rs do not trip simultaneously, then again the tripping command through the pole

discrepancy relay will initiate to trip the breaker and annunciation will appear in the sub

station control room and the UCB.


7.1.4 ISOLATORS:

Isolators are used to make or break the circuit on no load. They should never be operated

on load. The isolators installed in the sub station have a capacity of 1250 amperes. They

are double end break type, motor operated and can be operated from local as well as

remote.

7.2 TRANSFORMERS

7.2.1 CURRENT AND CAPACTIVE VOLTAGE TRANSFORMERS:

These are used for metering and protection. It should always be kept in mind that a CT

should never be open circuited and a PT should never be short-circuited.

7.2.2 LIGHTINING ARRESTOR AND ARC HORNS:

Protection against lighting.

7.2.3 CHANGE OVER SCHEMES (BUS TIE SYSTEM):

When main breaker is in service (on load change over):

1 Ensure Transfer bus is free (check any temporary earthing)

2 Charge the transfer by closing bus coupler isolator and circuit breaker.

3 Put the switches provided on bus coupler on generator control cum desk panel.

4 Charge the transfer bus by closing isolator d of GT.

5 Check the isolator of GT through which it has been already connected to the bus.

6 Close the isolator e,f, & g of tie Bus.

7 By using synchronizing trolley close the circuit breaker b1


BUS COUPLER TO MAIN BREAKER

o Close the isolator 1 & 3 of GT.

o Close the breaker a 1 of GT

o Close the isolator 5,7 & breaker b 1

o After this work close the isolator 9, 10

o By using synchronizing Troley, close the bus coupler breaker c1

7.2.4 SYNCHRONIZATION OF THE GENERATOR TO THE GRID

(Generator breaker is used)

With The Main Bus:

1. Close the isolator with the bus selection

2. Close the isolator on both sides of the generator breaker.

3. On Generator control desk panel(GCDP)

a. Put the switch NIT in normal position.

b. Put the synchroscope ON.

c. Measure the voltage and speed matching. Conditions will be included by

checking the synchronizing lamp on GCDP and close the generator

breaker.

IMPORTANCE OF THE TRANSFER BUS

Transfer bus is normally free and is used to facilitate repairing job of other breakers by

transferring load on transfer bus


7.3MAINTENANCE JOBS TO BE DONE ON 220KV SWITCH YARD

7.3.1 Daily Job

Visual checking for any hot spot

Checking of air leakage from the breaker

Checking for any gas leakage from the breaker

Checking of air pressure of breaker

Checking of gas pressure of breaker

Checking of oil leakage form CT and CVT

Checking of oil level from CT and CVT

Checking of lubricating oil level in compressors

Checking healthiness of trip circuit for all breakers.

7.3.2. Monthly Job

Thermo vision scanning of conductor joints and attending to the hot spot on available

opportunity

Breaker operation checking from local and remote

Isolators operation from remote and local.

Measurement of specific gravity and voltage of 220 V D. C> Battery cells.


7.3.3. Quarterly Job

1) Breakers

1. Tightening of breaker clamps

2. Cleaning of breaker cubicles

3. Checking of oil level of compressors of SF6 breakers.

4. Lubrication of rollers, mechanism shafts, anti pumping pin and c clips.

5. Checking operation of breakers through trip coil 1, trip coil 2, both the coils,

anti pumping operation and pole discrepancy operation

6. Checking of pressure of gas and air pressure of breakers.

2) Isolators

1. Tightening of the jumper clamps

2. Tightening of electrical connections

3. Cleaning of male female connections

4. Checking of fuses and replacement there F.

5. Checking of operation of isolators

3) Current transformers

1. Checking of oil level.

2. Checking of oil and leakage

3. Tightening of jumper clamps

4. Tightening of electrical terminal secondary connection


4) Lightning Arrestors

1. Tightening of jumper connections

2. Tightening of earthing connections

3. Checking of counter reading

4. Checking of porcelain part

5. Checking of grading current

5) Capacitive Voltage Transformer

1. Checking of oil level and leakage

2. Tightening of HT jumper clamps.

3. Tightening of secondary terminal connections

6) Battery 220 V D. C.

1. Cleaning of battery terminals

2. Tightening of battery terminal connections

3. Recording of specific gravity and voltage of each cell.


7.3.4 DURING ANNUAL SHUT DOWN OF UNITS

1) Breakers

1. Checking and cleaning of porcelain part of the breaker.

2. Tightening of breaker clamps.

3. Cleaning of breaker cubical

4. Tightening of all the terminal connection

5. Lubrication of I) C and D Roller (II) Locking pins (III) Anti Pumping pins

(IV) Mechanism Shafts

6. Recording of closing and tripping of each phase

7. Recording of insulation resistance value of breaker

8. Checking of annunciator and inter locks.

a. Air pressure low

b. Air pressure very low trip circuit cut off

c. Gas pressure low

d. Gas pressure trip circuit off and other ann. of breaker

9. Checking of tripping through

a. Trip Coil I

b. Trip Coil II

c. Through both the trip coils

d. Anti Pumping operation

e. Pole Discrepancy operation

10. Measurement of resistance of trip cells and closing coils

11. Checking of air leakage and its stoppage


12. Checking the gas leakage

13. Replacing the oil of compressors

14. Checking of auto operation of compressors

15. Complete maintenance of compressors

16. Checking of closing/tripping of breaker from local remote

2) Isolators

1. Cleaning of male female connections

2. Tightening of all the jumper clamps

3. Lubrication of control rotary post insulator with grease

4. Checking of proper operation of the isolator

5. Tightening of all the nuts and bolts

6. Cleaning the motor cubical

7. Tightening of all the terminal connections

8. Greasing the gear box of motor

9. Checking of all the fuses

10. Checking of operation of isolator from local/remote

3) Current Transformers

1. Checking / cleaning of porcelain part of CT

2. Checking of oil and level and stopping it if low

3. Checking of oil leakage and its stoppage

4. Checking of N2 pressure and maintaining it at 0.2 kg/cm2

5. Tightening of earthing connection

6. Checking of BDV value of CT oil

7. Tightening of all the secondary terminal connections

8. Cleaning of marshalling box and tightening of terminal connections

9. Recording of IR values of primary and secondary side of CT

10. Tightening of bushing clamps.


4) Capacitive Voltage Transformers

1. Checking of oil level and topping thereof

2. Checking of N2 pressure and maintaining it at 0.2 kg/cm2

3. tightening of jumper clamps.

4. Tightening of secondary connection

5. Recording of IR values of primary and secondary side

6. BD value of oil

5) Lightning Arrestors

1. Cleaning of porcelain part and checking

2. Tightening of earthing connection

3. Tightening of jumper connection

4. Recording of IR values

5. Checking of counter readings

6. Checking of grading current


CHAPTER-8

DC SYSYTEM & POWER LINE CARRIER

COMMUNICATION

8.1 DC SYSTEM

8.1.1 BATTERIES

Main Building

• Wet cell battery bank

o 125 V Battery Bank – 1






• Dry cell battery

o Battery Bank

8.1.2 SWITCHYARD BUILDING BATTERY BANK

220 V Battery Bank – 1




8.1.3 BATTERY ROOM

Battery room should be well ventilated, clean, dry and temperature moderate

(Damping is dangerous due to possibility of earth leakage from the battery)

Smoking is prohibited


Battery get best result at the room temperature between 20 – 35o C

8.1.4 ELECTROLYTE

It is a mixture of Acid and Pure Water (Distilled) with proper portion.

General value of proportion is 85 % water and 15 % acid.

Gravity to be maintained 1.200 + 0.005 in al the cells.

CAUTION

Batteries and Battery Room should be clean, dry and well ventilated.

Never allow a flame, cigarette near the batteries.

Wear old clothes or terylene when working with acid or electrolyte (Terylene is

resistant to dilute acid).

Never add water to acid. It will spurt dangerously

8.1.5 TEMPERATURE CORRECTION

The specific gravity of the electrolyte works with temperatire. Any reading

observed on the hydrometer should therefore be corredted to 270o C as all the

specific gravity values indicated by use are at 27o C

For every 1o C above 27o C add 0.007 to the specific gravity as read on

hydrometer

8.1.6 NORMAL OPERATION OF BATTERIES

Keep the battery on trickle charge continuously (25 hrs. each day) except where it

is on discharge or on Boost charge.

The trickle charge current shown on milli ammeter should be so adjusted that the

battery be kept fully charges without being over charged.

The trickle charging current should be so appropriate that it should neither be too

much trickle charge not too little trickle charge.

The value above 2.3 and below 2.25 volts per cell during routine checking it

found means adjustment of trickle charging current is required.


8.2 POWER LINE CARRIER COMMUNICATION

8.2.1 EARTH SHIELDING

It is a mesh of wire upon the tower. Its main purpose is to protect the substation

equipment from direct lightning strokes. Metallic body of each equipment is properly

earthed. The earthing resistance of any switch yard is about 0.2 ohm. Before the building

up of the sub station earthing material of G. I. wire is buried in the ground whose depth

depends upon the moisture content of ground. Earthing electrodes are provided at various

points. This increases the number of parallel provided at various points. This increases

the number of parallel paths and hence resistance of earth decreases.

This is a technique in which power lines are used as communication lines by which we

can make contact with other substation

The range of frequency used for communication is 300 KHz to 500 kHz.

8.2.2 WORKING

The voice frequency if converted into electrical signal. These signals are super imposed

on a carrier frequency and transmitted on the line through a coupling capacitor. At the

receiving end wave trap does not allow the modulated signal to enter the power circuit

where as the coupling capacitor provides a low resistance path to this signal. This signal

is then given to the line matching unit. In the LMU this frequency is matched and after

wards filtration of signal is done. The signal is demodulated and again converted into the

voice signal, which is available at phone receiver.


RESULT AND CONCLUSION

The Summer Training completed in Dholpur Combined Cycle Power Project

(DCCPP) during the period 25th

May 09 to 17th

July 09 is successful in all respects. There

I studied Gas Turbine, Steam Turbine, Boilers and all equipments that are use for

generating the electricity.

On doing Summer Training there I came to know that DCCPP project is under the

RVUNL (Rajasthan Rajya Vidhyut Utpadan Nigam Ltd.) and It’s capacity is 330MW.

It has been a wonderful experience for me for working in DCCPP as a Trainee and

if given chance I would like to be a part of this Organisation.


BIBLIOGRAPHY

rvunl.com

google.co.in

wikipedia.org

Own Experience