Report Chandan

8/13/2019 Report Chandan

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INDUSTRIAL TRAINING REPORT-2012

Jai Narain College of Technology, Bhopal

Name of Student :

University ID Number :

Name of Training Place (Industry

Institution, Govt. Department, etc) :

Address of Training Place with

Telephone No. and Email :

Name and Designation of Training Incharge

(Under whom training was completed) :

Training Period : June 01 June 30, 2012

Training Subject :


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TRAINING REPORT

OF

ADANI POWER PLANT

Prepared By:-

Chandan kumar


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CERTIFICATE

Certified that Mr. Rama Kant Singh, a student of B.E. (Computer

Science and Engineering) from Jai Narain College of Technology &

Science, Bhopal was placed under the supervision of undersigned for

his Industrial Training at our Organization started from June 01, 2012

and ended on June 30, 2012. He was engaged in Computer Aided

Design (CAD) at our well equipped Laboratory. During his training

period he was busy in learning and operating the CAD system,

computing program with Pro Engineer and other software currently

in operation. Mr. Singh is hardworking person and punctual inattendance. His behavior and nature was liked by all the staff of our

organization. To the best of my knowledge, Mr. Singh bears a good

moral character. I wish him a better future.

Place. Signature of

the officer

Date. Name and

designation


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ACKNOWLEDGEMENT

The time we spent here at Adani power Ltd. has been a tremendous learning

experience. Not only we have learnt a lot by way of practical application of our

theoretical knowledge, we have also gained valuable insights into an exciting

industry, its dynamics, and the way a mega project erects.

For this I am grateful to my guide Mr. Himmat Rathod (HOD, CHP, APL)

and Mr. Vasant Patel (HOD, Switchyard, APL) for his valuable time, able

guidance, encouragement, feedback, support at every step and his timely inputs.

We would also like to thank all those who helped me in my vocational training.

Submitted By: Submitted To:

Chandan Kumar Mr. Kamlesh Jogi

(HR Dept., APL)


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CONTENTS

1. OBJECTIVES

2. INTRODUCTION

3. OVERVIEW OF POWER PROJECT AT MUNDRA4. COAL HANDLING PLANT

5. D.M AND R.O PLANT

6. BOILER

6.1.. DEFINITION OF BOILER

6.2.. BOILER CLASSIFICATION

7. COOLING TOWER

8. ELECTRICAL SYSTEM OVERVIEW

9. ELECTRICAL PROCESS IN PLANT

10.ELEMENTS OF ELECTRICAL SYSTEM

11.SWITCHYARD INTRODUCTION

12.INTRODUCTION OF 330 MW UNITS

13.SWITCHYARD OF PHASE-I AND II

14.INTRODUCTION OF 660 MW UNITS

15.SWITCHYRAD OF PHASE-III AND IV

16.INTRODUCTION OF HVDC


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OBJECTIVES

Adani Power Ltd. is one of the upcoming projects of Adani Power, using Super

Critical Technology (660 MW Capacity Boiler), which is the second time in

India. Proposed Plant Capacity is 4620 MW (5 X 660 MW +4 X 330 MW),

which needs an investment of Rs195.00bn. So my basic objectives were:-

To get familiar with the working of a thermal power plant.

To understand the current technology that is being used in the erection of a

thermal power plant.

To get an overview of the major components of a thermal power plant.


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INTRODUCTION

Electricity is the only form of energy which is easy to produce, easy to

transport, easy to use and easy to control. So, it is mostly the terminal of energy

for transmission and distribution. Electricity consumption per capita is the index

of the living standard of people of place or country.

Electricity Demand and Supply in India:India is facing energy shortages of 11% of demand and even higher peak

shortages of 14%Demand-supply gap is more acute in Western region (where

70% of the Projects power will be supplied) with energy deficit at 16% and

peak deficit at 21%

Capacity additions of 160,000 MW required in the next 10 years satisfying

Indias power needs new capacity will need to come from a combination of

coal, hydro, gas, nuclear and wind projects

Types of Power Plants:

Electricity in bulk quantities is produced in power plants, which can be

of the following types:

Thermal

Nuclear

Hydro

Gas turbine

Geothermal


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Thermal Power Plant: - Here the main fuel is used as a coal and then its steam

is used to rotate the turbine and it generates the electricity.

Nuclear Power Plant: - Here the main fuel is used as a nuclear fuel and its

process is repeated.

Hydro Power Plant: - In this power plant the turbine is rotated with the help of

water which is then used to produce electricity.

Gas Turbine Power Plant: - In this power plant the gas is used to rotate the

turbine. This gas can be produced from anywhere and is used to generate the

electricity.

Geothermal Power Plant: - The temperature difference between core of the

planet and its surface drives a continuous conduction of thermal energy in the

form of heat from the core to the surface. And this heat generated due to above

temperature difference is used to produce the electricity.

Indias Installed Capacity (132329 MW)

55%

10%

26%

3%

6%

Coal & Lignite

Gas

Hydro

Nuclear

Other Renewables


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Mundra Thermal Power Project

Power Generation Capacity

Adani Groups foray into power sector

The Groups foray into power sector is natural extension for Adani Group,

which has emerged as Indias largest coal importer and second largest power

entity in the country.

Adani Power Ltd (APL) is setting up a 4620 MW power project at Mundra

based on imported coal. The execution will be done in the following ways as

under:-

2*330 Phase I (sub critical)

2*330 Phase II (sub critical)

2*660 Phase III (super critical) 3*660 Phase IV (super critical)

PLANT CAPACITY

4620 MW

PHASE I PHASE II PHASE III

2 x 330MW 2 x 330MW 2 x 660MW

PHASE IV

3 x 660MW

Largest

Power Plant

In

INDIA ON

3rd

Largest

Thermal

Power Plant

In

World


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COAL HANDLING PLANT AND COAL MILL:

What is C.H.P ???

The Coal Handling Plant is envisaged for unloading of coal received in

wagons and conveying the unloaded coal to bunkers through crushers ,

alternatively staking the crushed or uncrushed coal, reclaiming and supplying

coal to the coal bunkers. The reclaiming process included the systems of

stacker-cum-reclaimers or through reclaiming hoppers from uncrushed coal

yard or crushed coal yard. There is a three types of switches are placed for the

protection of the conveyor belt. One is the Pull Quote Switch which is used for

emergency stop of the belt. This type of switch is placed at every 50 m distanceon the belt conveyor. Second one is the Belt Sway Switch which is used for

balancing of the belt if the belt is shifted from the centre of the pulley to the left

or right side then this type of switch will be close by the pressure of the belt.

This type of switch is placed at the Header, Centre and Ending of the belt

conveyor. Third switch is the Zero Sway Switch which is used for the giving the

feedback to the PLC system which is controlling the whole system.

COAL ANALYSIS

In thermal power plants PROXIMATE analysis is used to evaluate the

quality of coal.

Proximate analysis: It consists of analyzing the coal for

1. Moisture.

2. Ash

3. Volatile matter

4. Fixed carbon

5. Gross calorific value(GCV ) or Useful heat value (UHV )


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Types of Coal % Carbon

Peat 51-59

Lignite 59-75

Sub-bituminous 75-80

Bituminous 80-91

Carbonaceous 91-93

Anthracite 93-95

COAL MILL PROCESS:

Main parts of coal mill are:

Gear Plate

Motor

Gear Box

Bottom Housing

Grinding track carrier and Scraper

Grinding track and nozzle ring

Grinding Roller

Loading Frame

Housing Case

Hydraulic Cylinder

Rotary Unit

Rotary Classifier

Oil Lubrication Unit


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D.M.PLANT AND R.O.SYSTEM

The main requirement of Boiler is water and coal for the production of steam.

Sea Intake draws water from the sea which is then passed to 20MLD and 7MLD

where MLD stands for Million litres per day.20MLD is used for 660 MW unitsand 7MLD is used for 330 MW units.

This water is then passed to the RO plant (where Reverse Osmosis takes place)

for reducing its conductivity and heavy water is removed as waste which is

expelled back to sea. The conductivity of water is as high as 75000 W/m^2K

which if passed will damage the turbine vanes and will also corrode the blades.

Hence it is necessary to reduce the conductivity from 75000 W/m^2K to 1500

W/m^2K which is performed in RO plant. The RO purified water is stored in

RO tank which then goes to DM plant for the removal of the many impurities

present in water like Na,Cl,Mg,Ca etc.

In DM plant there are many purification systems like anion exchanger, strong

acid cat ion exchanger,degazer etc.There are many Resin plates for removing

the positive and negative ions from water. In anion exchanger there are R-H+

resin plates and in cat ion exchanger there are R-OH- resin plates so that if NaCl

is present in water then Na+ and Cl- can be removed by these R-H+ and R-OH-

plates.

The reaction can be explained as follows: The Na+ ion bonds with R replacing

H+ which then bonds with Cl- forming R-Na+ and HCl.

R-H+ NaCl R-Na+ HCl

This HCl goes to the strong acid cat ion exchanger where R-OH- plates are

present which results in the formation of H2O and R-Cl.The reaction is

expressed as:

R-OH + HCl R-Cl + HO

The water thus produced is then stored in DM storage Tank which is then

passed to the boiler for the production of the steam. To obtain the original R-H+

and R-OH-, HCl & NaOH are passed through the anion exchanger & cation

exchanger respectively .The by-product of the above process is NaCl which is

drained out by other process.


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BOILER:Definition of boiler ;

Boiler a Pressure vessels used for generating (a) steam for powergeneration, process use or heating purposes and (b) hot water for heating

purposes.

However, according to the Indian Boiler Act, 1923, a boiler is a

closed pressure vessel with capacity exceeding 22.75 litres used for generating

steam under pressure. It includes all the mountings fitted to such vessels, which

remain wholly or partly under pressure when steam is shut off.

Various Types of Boilers:

Fire Tube Boiler

Water Tube Boiler

Fire Tube Boiler:

Cornish Boiler

Simple vertical boiler

Cochrane boiler

Locomotive Boiler

Scotch Marine Boiler

Water Tube Boiler:

Benson Boiler

Waste Hear Boiler


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Fire Tube Boilers:

A fire tube boilers, is the boiler wherein the products of combustion pass

through inside of the tubes (either one or several) and water which is to be

converted in to steam is made to surround outside these tubes. Fire Tube Boilersare used where the steam pressure is normally low and the steam is not

generally required to be the superheated. Fire tube boilers are compact and can

be easily manufactured in a factory and assembled as a packaged boiler. Fire

tube boilers cannot be manufactured in large sizes beyond certain limit due to

large size of shell involved.

Fire tube boilers have the advantage of low manufacturing and operating

cost.

Water Tube Boilers:

In this type of construction of Boilers the fuel is fired in a confined

chamber and the water is circulated through divided flow path inside a number

of small-bore tubes, which are exposed to the heat generated inside the

combustion chamber. In Adani power plant water tube boiler is used.

Water tube are classified as

Sub critical boiler

Super critical boiler


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Difference between Sub-Critical and Super-Critical Boilers

SUB-CRITICAL BOILERSSUPER-CRITICAL

BOILERS

Operating pressure is below 225.5

bar.

Operating pressure is above 225.5

bar.

Normal circulation: circulation by

pump assisted or natural circulation.

Lower load start-up circulation:

below 35% NR load.

Power plant efficiency is around

35%.

Power plant efficiency is around

39%.

Pressure : 169 bar

SH Temp : 538C

RH Temp : 538C

Pressure : 254 bar

SH Temp : 571C

RH Temp : 569C

Base Additional cost to manufacturing and

erection of furnace wall.

Vertical water walls. Spirally wounded tilted water walls.

Spirally wounded water walls

ensures:

Uniform heat distribution.

Avoid higher thermal stresses in

water-walls by reducing the fluid

temp. difference in adjacent tubes.

Drum is used Drum is not used


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COOLING TOWER

Cooling tower is used for the purpose of cooling the heated sea water. In

electricity generation process steam passes through the H.P, I.P, L.P Turbines

but there is some heat which is present reduces the efficiency for next cycle. So

this heat is transferred to the sea water via use of condenser.

Here the sea water is feed into the condenser which transfers the heat of steam

to the sea water. This sea water is transferred to the cooling tower through the

pipes. In cooling tower according to the design it will flow to the upper head of

the cooling tower. At the top portion L.T motors are present which fetches the

cool air from the atmosphere. The flow of air is from top to ground which cools

the water.

Here water free falls on the fins. There is some space for the circulation of

natural atmospheric air throughout the cooling tower. By this way water looses

its heat and water is now feed to the circulating water pump through

underground water canal system.


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ELECTRICAL SYSTEM OVERVIEW

In Adani Power Plant it consist of 9 units in which unit 1,2,3,4 are subcritical

and unit-5, 6, 7, 8, 9 are supercritical plants. The power generated by these units

is then transferred to the necessary parts of Gujarat.

For the transmission of this power in Adani Power Plant four switchyard

units are placed. In which the first switchyard unit gets the power from

Unit-1 & Unity-2 and its capacity is of 220 KV. The second Switchyardunit gets the power from Unit-3 & Unit-4 and its capacity is of 400 KV.

The Third Switchyard Unit gets the power from Unit-5 & Unit-6 and its

capacity is of 400 KV. The Fourth Switchyard Unit gets the power from

Unit-7, Unit-8 & Unit-9 and its capacity is of 400 KV. Here STATIONTRANSFORMER units are also used for the input power of Plant in case

of failure or breakdown of entire plant power.

This power is supplied by the Government of Gujarat i.e. GEB to the

station transformer and it is then distributed in the plant. The powergenerated by the plant via turbines is the supplied to the Generating

transformer and it is then distributed to the switchyard units respectively.

Another small transformers of lower capacity i.e. Unit Auxiliary

Transformer UATs are then supplied power from the turbo generators

and then they are distributed. It consists of two UATs which is of 6.6 KV

output and is used for running the auxiliaries fitted in the plant.

For the Backup plan the another two systems are made they are

1) Battery Backup Plan

2) D.G.SET Backup Plan


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ELECTRICAL PROCESS IN PLANT

ADANI POWER PLANT comprises of 9 units. It is mainly divided into 4phase. Phase 1 consists of unit-1 & 2. Phase 2 consists of unit-3 & 4. Phase 3

consists of unit-5 & 6 and phase 4 consists of Unit- 7, 8, & 9. Capacity of plant

is 4620 MW. Unit 1 to 4 has a capacity of 330 MW and Unit 5 to 9 has capacity

of 660 MW. Generated power is then distributed to the different commercial

area as well as industrial and SEZs area through the different switchyard and

some amount of power is used for the plant to run the plant auxiliaries like

motors, control circuits, etc.

In Unit 1 to 4 the mechanical energy generated by the high pressure,

intermediate pressure and low pressure turbine is then transferred to the

electrical energy by turbo alternator. Here the turbine is used as a prime mover

for the turbo alternator. So by use of prime mover the armature winding rotates

in the magnetic field which is produced by the field pole and the magnetic field

is constant and when the armature winding cuts the magnetic field and induced

EMF is generated and we can obtain this EMF via brush. This generated EMF is

also called terminal voltage.

TURBO GENERATOR

TYPE 1255-460 RATED EXCITING

VOLTAGE

542 V

RATED OUTPUT 330000

KW

RATED EXCITING

CURRENT

2495 A

RATED VOLTAGE 24000 V ROTOR WINDING

COOLANT

H2

RATED CURRENT 9339 A STATOR WINDING

COOLANT

H20


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POWER FACTOR 0.85 ROTOR WINDING

INSULATION TYPE

F CLASS

FREQUENCY 50 STATOR WINDING

INSULATION TYPE

F CLASS

SPEED 3000 STATOR CORE &

ROTOR COOLANT

H2

ABSOLUTE

HYDROGEN

PRESSURE

0.4 STANDARD IEC

CONNECTION STAR PROTECTION TYPE IP54

Now the generated voltage is then distributed to the different areas and also

some part of power is used for the internal auxiliaries of the plant and for that it

passes through different networks and different equipments. The power which is

used for distribution is first send to the generating transformer and it is then

distributed to the different areas by different networks and different switchyard.

POWER THAT IS USED FOR PLANT AUXILIARIES

In ADANI POWER PLANT there is mainly two type s of auxiliaries which is

operated by 6.6. KV and 415V. The auxiliaries operated by 6.6 KV are known

as H.T. auxiliaries. The auxiliary which is operated by 415 V is known as L.T.

auxiliaries. So to operate these types of auxiliaries we need 6.6 KV and 415Volt supply. Without these auxiliaries we cannot start up the plant. So first of all

we have to take this electric power from the outsource from GEB or other

power plant and it is in form of 220 KV. In ADANI POWER PLANT for each

unit there is one station transformer which is used to step down the voltage at

6.6 KV.


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ELEMENTS OF ELECTRICAL SYSTEM: -

1) Lightning arrestor: -

A lightning arrester is a device used on electrical power systems and

telecommunications systems to protect the insulation and conductors of the

system from the damaging effects of lightning. The typical lightning arrester has

a high-voltage terminal and a ground terminal. When a lightning surge (or

switching surge, which is very similar) travels along the power line to the

arrester, the current from the surge is diverted

through the arrestor, in most cases to earth.

In telegraphy and telephony, a lightning arrestor

is placed where wires enter a structure, preventingdamage to electronic instruments within and

ensuring the safety of individuals near them.

Smaller versions of lightning arresters, also called

surge protectors, are devices that are connected

between each electrical conductor in power and

communications systems and the Earth.


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2)Current Voltage Transformer: -

A capacitor voltage transformer (CVT), or capacitance coupled voltage

transformer (CCVT) is a transformer used in power systems to step down extra

high voltage signals and provide a low voltage signal, for measurement or to

operate a protective relay. In its most basic form the device consists of three

parts: two capacitors across which the transmission line signal is split, an

inductive element to tune the device to the line frequency, and a transformer to

isolate and further step down the voltage for the instrumentation or protective

relay.

The tuning of the divider to the line frequency makes the overall division ratio

less sensitive to changes in the burden of the connected metering or protection

devices. The device has at least four terminals: a terminal for connection to the

high voltage signal, a ground terminal, and two secondary terminals which

connect to the instrumentation or protective relay.

CVTs are typically single-phase devices used for measuring

voltages in excess of one hundred kilovolts where the use of

wound primary voltage transformers would be uneconomical.

In practice, capacitor C1 is often constructed as a stack of

smaller capacitors connected in series.


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3) ISOLATORS: -

A disconnected or isolator switch is used to make sure that an electrical circuit

can be completely de-energised for service or maintenance. Such switches are

often found in electrical distribution and industrial applications where

machinery must have its source of driving power removed for adjustment or

repair.

High-voltage isolation switches are used in electrical substations to allow

isolation of apparatus such as circuit breakers and transformers, and

transmission lines, for maintenance. Often the isolation switch is not intended

for normal control of the circuit and is used only for isolation; in such a case, it

functions as a second, usually physically distant master switch (wired in series

with the primary one) that can independently disable the circuit even if the

master switch used in everyday operation is turned on.

There are two types of isolators: -

1) Single break type isolator

2) Double Side Double Break type isolator


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4) CIRCUIT BREAKER: -

A circuit breaker is an automatically operated electrical switch designed toprotect an electrical circuit from damage caused by overload or short circuit. Its

basic function is to detect a fault condition and, by interrupting continuity, to

immediately discontinue electrical flow. Unlike a fuse, which operates once and

then must be replaced, a circuit breaker can be reset (either manually or

automatically) to resume normal operation. Circuit breakers are made in varying

sizes, from small devices that protect an individual household appliance up to

large switchgear designed to protect high voltage circuits feeding an entire city.


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5) CURRENT TRANSFORMER: -

A current transformer (CT) is used for measurement of electric currents. Current

transformers, together with voltage transformers (VT) (potential transformers

(PT)), are known as instrument transformers.

When current in a circuit is too high to directly apply to measuring instruments,

a current transformer produces a reduced current accurately proportional to the

current in the circuit, which can be conveniently connected to measuring and

recording instruments.

A current transformer also isolates the measuring instruments from what may be

very high voltage in the monitored circuit. Current transformers are commonly

used in metering and protective relays in the electrical power industry.


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6) WAVE TRAP:-

Line trap also is known as Wave trap. This is relevant in Power Line Carrier

Communication (PLCC) systems for communication among various substations

without dependence on the telecom company network. The signals are primarily

teleportation signals and in addition, voice and data communication signals.Line

trap also is known as Wave trap. What it does is trapping the high frequency

communication signals sent on the line from the remote substation and diverting

them to the telecom/ teleportation panel in the substation control room (through

coupling capacitor and LMU).

This is relevant in Power Line Carrier Communication (PLCC) systems for

communication among various substations without dependence on the telecom

company network. The signals are primarily teleportation signals and in

addition, voice and data communication signals.

The Line trap offers high impedance to the high frequency communication

signals thus obstructs the flow of these signals in to the substation bus bars. Ifthere were not to be there, then signal loss is more and communication will be

ineffective/probably impossible.


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7) TRANSFORMER: -

A transformer is a device that transfers electrical energy from one circuit to

another through inductively coupled conductorsthe transformer's coils. A

varying current in the first or primary winding creates a varying magnetic fluxin the transformer's core and thus a varying magnetic field through the

secondary winding. This varying magnetic field induces a varying electromotive

force (EMF), or "voltage", in the secondary winding. This effect is calledinductive coupling.

If a load is connected to the secondary, current will flow in the secondary

winding, and electrical energy will be transferred from the primary circuit

through the transformer to the load. In an ideal transformer, the induced voltage

in the secondary winding (Vs) is in proportion to the primary voltage (Vp) and isgiven by the ratio of the number of turns in the secondary (Ns) to the number ofturns in the primary (Np) as follows:

By appropriate selection of the ratio of turns, a transformer thus enables an

alternating current (AC) voltage to be "stepped up" by making Nsgreater than

Np, or "stepped down" by making Nsless than Np. The windings are coils

wound around a ferromagnetic core, air-core transformers being a notableexception.


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8) REACTORS: -

Essentially a reactor is an inductor. Physically it is a coil of wire that allows a

magnetic field to form around the coil when current flows through it. When

energized, it is an electric magnet with the strength of the field beingproportional to the amperage flowing and the number of turns.

A simple loop of wire is an air core inductor. More loops give a higher

inductance rating. Quite often some ferrous material such as iron is added as a

core to the winding. This has the effect of concentrating the lines of magnetic

flux there by making a more effective inductor.

9) INSULATOR: -

A true insulator is a material that does not respond to an electric field andcompletely resists the flow of electric charge. In practice, however, perfect

insulators do not exist. Therefore, dielectric materials with high dielectric

constants are considered insulators. In insulating materials valence electrons are

tightly bonded to their atoms. These materials are used in electrical equipmentas insulators or insulation. Their function is to support or separate electrical

conductors without allowing current through themselves. The term also refers to

insulating supports that attach electric power distribution or transmissionconductors to utility poles or transmission towers.


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SWITCHYARD INTRODUCTION: -

A Switchyard or Substation, consisting of large breakers and towers, is usually

located in an area close to the plant. The substation is used as the distribution

center where:

electrical power is supplied to the plant from the outside, and

electrical power is sent from the plant

Often there are at least 2 main Buses. Very high voltages (typically 220,000 or

345,000 volts) are present. Gas and oil circuit breakers are used. The gas (e.g.

sulphur hexafluoride) or oil is used to extinguish the arc caused when a breaker

is opened, either by a control switch or due to a fault. Manually or motor

operated disconnects are provided on either side of the breaker to allow the

breaker to be electrically isolated so that maintenance work can be performed.

Switchyard forms an integral part of any power plant i.e. Industrial CPP,

Thermal Power Utilities, Gas Turbines based power plants or Hydel power

plants. These power plants have their main plant equipment integral controls

(Boiler / Turbine / Gas Turbine / Hydro Turbine) as well as plant DCS System

(BoP / Station C & I). While the entire power plant is integrated at the DCS

level, true unification is achieved by incorporating / integrating switchyardcontrols (SCADA) also in the plant DCS.

The Supervisory control and data acquisition system (SCADA) of switchyard

consists of Operator Stations, Engineer's Stations, Historical Storage,

Computers and associated peripherals and the switchyard bay control systems

interconnected through a high speed network .

The system constitutes several operator work stations and engineer's work

station with high resolution Colour display monitors, touch screen, function key

board, mouse, track ball and printers.

The system collects digital and analog information available throughout the

plant and presents information in various graphic displays, alarms, logs.


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INTRODUCTION OF 330MW UNITS:

There are four units of 330 MW which consists of four 24KV generator coupled

to their respective turbines. Generators are having two types of cooling systems.

Stator winding is having Water Cooled system and Stator core, Rotor windingand Rotor core having Hydrogen cooled system. There are two UATs (Unit

auxiliary transformers),one station transformer, one generating transformer per

unit. Generator generates 24 KV which is stepped up by generating transformer

to 220KV, which then is transmitted to Nanikhakhar and Tapper via the

switchyard .There are two tapings that emerge from 24 KV line which is fed to

the two UATs which steps down 24 KV to 6.6 KV .The secondary of UAT is

connected to 6.6 KV bus which is used to feed the H.T motors. Further there is

another transformer that steps down 6.6 KV from UAT to 415V which is usedto feed the L.T motors. H.T motors are used in RO plant and sea intake.L.T

motors are used in LDO, HFO,DM Plant,Cooling Tower,etc.

In case of black out the S.T draws power from GEB (Gujarat Electricity Board)

from the same 220KV bus and steps down to 6.6 KV which is used to drive the

auxiliary equipments /Components so as to enable the plant to generate power.

The generator used in 330 MW units is provided with Brushless DC excitation.

The 330 MW unit also consists of control panel which works on 220 V DCsupply. The control panel indicates the amount of current flowing as well as the

voltage of the auxiliary components and the protective devices used for

protection purpose. A control panel consists of Relays,Earth switch,CTs,Circuit

Breakers,Fuses,MCB,etc.

Rating of the STEAM TURBINE GENERATOR is as follows:

Output Power: 330 MW Power Factor: 0.85

Voltage : 24000 V Phase : 3

Current : 9339 A Speed : 3000 r/min

Frequency : 50 Hz


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Switchyard Phase-I & II:

It is define as an assembly of apparatus which transforms the characteristics of

electrical energy from one form to another i.e. AC to DC or from one voltage to

another.

And The LAYOUT of switchyard is the most convenient location where

systematic electrical apparatus arrangement done.

The switchyard is the interconnecting link between the Power Station and the

consumer. Generator generates 24 KV voltages and then the generating

transformer which is Delta/Star connected generates 220 KV voltages and by

the means of conductors the power is supplied to the MRSS lines. In between

there are many important apparatus are connected like Lightning Arrester, CVT,Isolator, Circuit Breaker, Current Transformer. There are two current

transformer are used one is for the Protection purpose and second one is for the

measuring purpose.CT for measuring purpose is having Two core on the

secondary side and which is for Protection purpose having 5 core on secondary

side. Phase I is having transfer bus for supplying power to the MRSS in case of

any one of the main bus is having the problem of maintenance or if the fault

occurs in main bus then we can switchover to the transfer bus and supply the

power to the load. Phase I is having BUS SECTIONALISER which is havingCT, Isolator and SF6 Circuit Breaker. For connecting the Phase I and II there is

a Inter Connected Transformers are placed which has a rating of 220/400 KV,

315 MVA. There are two ICT placed in the Phase I and II. Phase I is having

Line Conductor for the bus system and Phase II is having Pipe Bus System and

having 1.5 Circuit Breaker Scheme which means between the two main bus

there is a Three Circuit Breakers are placed. Phase I is having 220 KV

switchyard and Phase II is having 400 KV switchyard. Phase I is having all

control panels in the control room i.e. relay,fiber optic system etc. And 400 KVswitchyard is having all the controlling devices in the field and only fibre optic

system is in the control room.


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220 KV SWITHYARD (Phase I)

Manufacturer and Main Supplier: ABB LTD.

220KV bus configuration system

2 Main Bus and 1 Transfer Bus scheme is used.

Main Bus 1 : 220 kV, 2500 A, 40 kA for 3 sec.

Main Bus 2 : 220 kV, 2500 A, 40 kA for 3 sec.

Transfer Bus : 220 kV, 1600 A, 40 kA for 3 sec.

8

Main System Parameters

Nominal Voltage : 220 kV

Rated System Voltage : 245 kV

Frequency : 50 Hz

No. of Phase : 3


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Basic Insulation Level BIL : 1050 kVp

1 Minute Power Frequency Withstand Voltage : 460 kV

Cree page : 31 mm/kV

Short Circuit Rating (Other than CT) : 40 kA for 3 sec.

Short Circuit Rating for CT : 40 kA for 1 sec.

INTRODUCTION OF 660 MW UNITS:

There are five 660 MW units consisting of five generators that are coupled to

five turbines (each turbine consisting of two LP turbines so that vary low

pressure steam can be produced).

These five generators generates 22KV which is stepped up to 400 KV by G.T

.There are two tappings that are taken from 22KV line that emerges from

generator which are fed to the UATs.

In 660 MW units the UATs consists of two tappings producing 6.6KV as well

as 11KV.11KV is produced so as to feed the 11MW boiler feeder pump motor

which is used to feed the demineralized water from the DM plant to the boiler

for production of the steam.The generators of 660 MW unit are given DCexcitation using carbon brushes i.e. it is given brush excitation. The brush

excitation is given by the excitation transformer which is step down voltages

from 6.6KV to 415 V and then Automatic Voltage Regulation room converting

AC voltages into DC voltages. DC voltages then supplied to the carbon brushes

i.e. positive and negative supply is given to the generator excitation scheme.

The 400KV that is stepped up by the generating transformer is then passed

through the RLC filter circuit to remove the ripples and to obtain a pure sine

wave and then is stepped down to 212 KV and is fed to the rectifier circuit.

There are two buses in the rectifier house. The rectifier circuit consists of

connection of many thyristors in series. Some of the thyristors are connected in

STAR and are connected to a bus where as some of them are connected in

DELTA and are connected to another bus. Its a Twelve pulse rectifier circuit

with a firing angle of 60.

The output of the rectifier circuit DC of 500KV magnitude which is then

transmitted to Haryana spanning 1050 km.


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Rating of the MDBFP Motor:

Rated Power : 11000 KW Rated current: 654 A Connection: STAR

Rated Voltage: 11000 KV Frequency: 50 Hz Speed: 1487 r/min

Switchyard Phase III & IV:

In APL there are 5 units of 660 MW. Phase III consisting of units 5 and 6. And

Phase IV is having units 7,8 and 9. Layout and design of the switchyard is same

for the Phase III and Phase IV. Generator generating 22 KV and this voltages

directly connected to the Generating Transformer which is stepped up the

voltages from 22 KV to 400 KV. In 660 MW units there are Three Single Phase

transformers are connected for the generating purpose. Due to higher cost of the

insulation providing in the transformer there are three single phase transformer

are connected instead of connecting one three phase transformer. After the

generation of the 400 KV voltages this voltages are supplied to the HVDC

system of the 500 KV. In Phase III and Phase IV switchyard there is a Reactor

is placed for the reducing the reactance of the line. Due to the Ferranti Effect the

at the receiving end of the line the capacitance and reactance of the voltages will

be higher and it will cause damage of the equipment which is connected at the

receiving end. So for that reactor are connected in this phase. Reactor is

connected to the main bus and the output of the reactor is grounded. This

switchyard is also having One And Half Breaker scheme. Which is very costly

as compared to the other scheme. In this scheme there are three breakers are

placed one is at the Bus-1 , second one is the Tie Circuit Breaker which is used

for the connecting the two Bus and the third one circuit breaker is placed at the

Bus-2.There are many protection devices are connected in Bay like Current

Transformer for the measuring the value of current, Isolator, Earth switch.

Earth switch is provided for the earthing purpose and isolator is placed for the

protection of circuit breaker. Isolator is always run on OFF Load. When

anything is happened in the circuit breaker the isolator will be opened and

maintenance of the circuit breaker will be done. Isolator is placed both the sidesof the circuit breaker.


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INTRODUCTION TO THE HVDC:

Units 7,8 & 9 are generating 660 MW each. Steam Turbine generators are

generating 22 KV then these voltages are step up to the 400 KV. These voltages

are step up by the generating transformer. Next the power will be supplied to

the HVDC department for generating 500 KV DC voltages. In Gujarat only

ADANI POWER having this type of HVDC Sub-Station. In this sub-station the

voltages will be taken from the generating transformer and by means of line

conductor voltages are applied to the capacitor filters are placed for the

reduction in the harmonic component and for generating reactive power. Thisreactive power is applied to the Three converting transformer each has a

capacity of 500 MVA. These converting transformers are used for the step

down voltages from 400 KV to 211 KV.

Transformer having two types of bushing big and small. Big bushing is used for

the Star type connection because in the star connection the current is higher and


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the voltages are less as compared to the current. Small bushing is used for the

Delta type connection because in this winding voltages is higher than the

current. After that the voltages are applied to the Thyristor which converting

AC voltages in DC voltages. For the transformer protection one control room is

there for operating the valves. This transformers are having the oil tank capacity

of 1,35,000 Ltr. Thyristor which is used for conversion process having 12 Pulse

with the firing angle of 60 degree. When the DC voltages are generated then the

Smoothing Reactor is placed between the generation station and transmission

lines. Smoothing Reactor is used for the smoothing the DC voltages. It is also

used for the protection against the faulty current. If the fault occurs in the

system it will ground the fault current. Then the 500 KV voltages are

transmitted to the HARYANA which is 1050 Km. far from the Mundra. HVDC

project is the Turn-Key project of SIEMENS. The overall cost of this project is

approx.1400 Corers. Special room is there for the thyristor and for other

equipments to generate 500 KV DC.

Report Chandan

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