Abstract

A

PRACTICAL TRAINING REPORT

ON

TRANSMISSION & DISTRIBUTION OF ELECTRICAL POWER

Taken at

“220KV G.S.S. MADAR, AJMER”

Submitted in partial fulfillment

For the award of the degree of

BACHELOR OF TECHNOLOGY

(Rajasthan Technical University, Kota)

IN

ELECTRICAL AND ELECTRONICS ENGINEERING

SESSION (2011-2012)

SUBMITTED TO: SUBMITTED BY:

Mr. RAHUL GARG Anshu Sharma

HOD OF EEE BRANCH EEE (VII SEM)

DEPT. ELECTRICAL & ELECTRONICS 080013003

DEPARTMENT OF ELECTRICAL AND ELECTRONICS

ENGINEERING

GOVT.MAHILA ENGINEERING COLLEGE AJMER

NASIRABAD ROAD, MAKHUPURA, AJMER-305002

ACKNOWLEDMENT

It was highly educative and interactive to take training at 220KV G.S.S. MADAR,

AJMER as technical knowledge is incomplete without the practical knowledge, I couldn‘t find

any place better than this to update myself. I am highly grateful to our training co-coordinator

Mr. M.K. JARWAL (XEN) to grant me permission to take training at such a coveted institute. I

am also thankful to all those ENGINEERS & TECHNICIANS without whom it was not possible

for me to clear my doubts and difficulties.

I am grateful to training in-charge Mr. P. C. Tiwari (AEN) for giving guidelines to

make the project successful.

I want to give sincere thanks to the principal, Prof.M.C.Govil for his valuable

support.

I extend my thanks to Mr. RAHUL GARG Head of the Department (E.E.E.) for his

cooperation and guidance.

(Signature) Yours sincerely,

Mr. Rahul Garg Anshu Sharma

HOD of EEE 7th semester

EEE

GWECA

TABLE OF CONTENTS

Chapter No Title Page No

CERTIFICATE

ACKNOWLEDGEMENT

ABSTRACT 1

1 INTRODUCTION 2

SINGLE LINE DIAGRAM 3

CLASSIFICATION OF SUB – STATION 4

2 LIGHTNING ARRESTAR 5

2.1 CONSTRUCTION

2.2 ACTION

2.3 TYPE OF LIGHTENING ARRESTER

2.4 APPLICATION OF LIGHTING ARRESTER

3 POTENTIAL TRANSFORMER 7

3.1 APPLICATION

3.2 SPECIFICATION

4 CURRENT TRANSFORMER 9

4.1 CONSTRUCTION

4.2 SPECIFICATION OF C.T

5 ISOLATORS 11

5.1 CONSTRUCTION

6 CIRCUIT BREAKER 13

6.1 OPERATING PRINCIPLE

6.1.2 OPERATION

6.1.3 ADVANTAGE

6.1.4 DISADVANTAGE

6.2 AIR BLAST CIRCUIT BREAKER

6.2.1 CONSTRUCTION

6.2.2 DISCRIPTION

6.2.3 PRINCIPLE

6.3 VACUUM CIRCUIT BREAKER

6.3.1PRINCIPLE

6.3.2 CONSTRUCTION

6.3.3 WORKING

TABLE OF CONTENTS

Chapter No Title Page No

6.4 OIL CIRCUIT BREAKER

6.4.1 SPECIFICATION OF OIL CIRCUIT BREAKER

6.5 SF6 GAS CIRCUIT BREAKER

6.5.1 CONSTRUCTION

6.5.2 PHYSICAL PROPERTIES OF SF6 GAS

7 BUSBARS 20

8 INSULATOR 21

8.1 TYPES OF INSULATOR

8.1.1 PIN INSULATOR

8.1.2 SUSPENSION INSULATOR

8.1.3 STRAIN INSULATOR

9 POWER TRANSFORMER 23

9.1 TYPES OF POWER TRANSFORMER

9.2 INDICATOR APPARATUS

9.3 CORE AND FRAME

9.4 TRANSFORMER WINDING

9.5 BUSHING

9.6 TAP CHANGER

9.6.1 ON LOAD TAP CHANGER

9.7 CONSERVATOR

9.8 BUCHHOLZ RELAY

9.8.1OPERATION

9.8.2 CONSTRUCTION

9.8.3 ADVANTAGE

9.8.4 DISADVANTAGES

9.8.5 TANSFORMER OIL TESTING

10 EARTHING 29

11 CONTROL – ROOM 30

12 D.C SYSTEM 31

13 COMPRESSOR-ROOM 33

14 POWER LINE CARRIER COMMUNICATION SYSTEM 34

TABLE OF CONTENTS

Chapter No Title Page No

14.1 COUPLING CAPACITOR

14.2 LINE TRAP UNIT

14.3 PROTECTION & EARTHING OF COUPLING CAPACITOR

14.4 ELECTRONIC EQUIPMENTS

14.4.1 TRANSMITTER UNIT

14.4.2 RECEIVING UNIT

14.4.3 ADVANTAGE OF POWERLINE COMMUNICATION

15 RELAYS 37

15.1 TYPES OF RELAY

15.1.1 OVER CURRENT RELAY

15.1.2 DISTANCE RELAY

15.1.3 DIFFERENTIAL RELAY

15.1.4 EARTH FAULT RELAY

16 CAPACITIVE BANK 39

16.1 SERIES REACTOR

16.2 RESIDUAL VOLTAGE TRANSFORMER

17 SAFETY MEASURES 40

18 CONCLUSION 41

19 REFERENCE 42

LIST OF FIGURES

SR. NO TITLE PAGE NO

1 SINGLE LINE DIAGRAM 3

2 LIGHTENING ARRESTOR 5

3 POTENTIONAL TRANSFORMER 7

4 BASIC DIAGRAM OF POTENTIONAL

TRASFORMER 8

5 CURRENT TRANSFORMER 9

6 BASIC DIAGRAM OF CURRENT

TRANSFORMER 10

7 ISOLATOR 11

8 CIRCUIT BREAKER 13

9 AIR BLAST CIRCUIT BREAKER 15

10 VACCUME CIRCUIT BREAKER 17

11 SF6 CIRCUIT VREAKER 19

12 PIN TYPE INSULATOR 21

13 SUSPENSION INSULATOR 22

14 STRAIN INSULATOR 22

15 POWER TRANSFORMER 23

16 BUCHHOIZ RELAY 27

17 TRANSFORMER OIL TESTING 28

17 CONTROL ROOM 30

18 WAVE TRAP 35

19 RESIDUAL VOLTAGE

TRANSFORMER 39

ABSTRACT

G.S.S. was set up in the year 1962, with the aim to supply according to load capacity of

Ajmer. It is of 220kV. The input supply may be coming from the generating station or any other

grid sub-stations.

At Ajmer G.S.S. two lines are coming on from “BEAWAR” & other from

“PHULERA” are of 220kV lines. Two bus of 220kV are charged from these lines. One is main

bus and other is Auxiliary bus.

There are two Transformer installed. One is of 100MVA (BHEL Make) & other is

100MVA (EMCO Make). Again, two bus bars of 132kV are charged from 132kV supply. 10

Feeders are taken from 132 kV bus. Three of them are going to “KISHANGARH”

“SARADHANA” & “BHERUNDA” and seven feeders are going to in Ajmer city.

There are five other transformers for convert 132kV to 33kV & 11kV. The two

transformers are of 20/25 MVA (EMCO Make), other is 10/12.5 MVA (ECE Make), and

remaining two are 2*7.5 MVA (WESTING HOUSE Make). These convert the 132kV into 33kV.

Now again two bus bar of 33kV are charged from 33kV supply & various feeders are taken from

33kV bus.

There are several devices connected for use in protection and for running

uninterrupted

1) L.A.

2) C.T.

3) P.T. OR [C.V.T.]

4) C.B.

5) ISOLATORS

CHAPTER 1.

INTRODUCTION

When India became independent, its overall installed capacity was hardly 1900MW.

During first year plan (1951-1956), this capacity was only 2300MW. The contribution of

RAJASTHAN STATE was negligible during 1st & 2nd 5 year PLANS.

The emphasis was on industrialization for that end it was considered to make the

power system of country more reliable & efficient. Therefore, Rajasthan State Electric Board

came as existence in July 1957.

In August 1972, Rajasthan atomic power project at Rawat Bhata (Kota) was

installed with generating capacity of 430MW & entered in nuclear power generating technology.

The power generating by Hydro & Thermal technology were also introduced. (The whole

progress of RSEB may be seen from the table attached.)

Despite of all genuine efforts by RSEB it became under heavy debt turning to

4300 crores. Board has to make payment of Rs. 2 crores everyday alone on this account. The

financial position has become very miserable. Leakage & theft of electricity could not be

checked. The recovery was so poor. The cost of generation of electricity being sold very cheaply

to the rural consumers causing the heavy depreciation of cost 220kV G.S.S. Ajmer is a part of

transmission system. Therefore, the board has been dissolved & five new companies are formed

as to serve better to the consumer in 19th July 2000.

The details of the companies are as follows:

Rajasthan Rajya Vidyut Prasaran Nigam Limited.

Rajasthan Rajya Vidyut Utpadan Nigam Limited.

Vidyut Vitaran Nigam Limited

Ajmer Vidyut Vitaran Nigam Limited.

Jodhpur Vidyut Vitaran Nigam Limited.

The supply of electricity to consumers is carried out through G.S.S. & SUB-

STATION

1.1 .SINGLE LINE DIAGRAM

PHULERA

BEAWAR

SARADHANA

BHERUNDA KISHANGARH

1.2. CLASSIFICATION OF SUB - STATION

1.2.1 THE ELECTRICAL SUB-STATION CAN BE CLASSIFIED IN SEVERAL WAYS

1. CLASSIFICATION BASED ON VOLTAGE LEVEL

A Sub-station is named in accordance with its higher voltage level e.i a 220 kv Sub-

station has higher voltage level of 220 kv standard rated voltages in India are 3.3, 6.6, 11, 33,

66, 132, 220 ,& 440 kV . These voltages refer to normal power frequency phase to phase A.C

voltage. There is generally two or more voltage level in Sub-station. The Sub-station is

designated after higher voltage level i.e. A 220 kV buses besides say 110 kV. 33 kV 3 kV and

400V buses. The Bus-Bars are either in two or three horizontal planes so as to permit proper

connection and clearances. Three level sub station are more compact but complex. Conventional

open terminals Sub-station are very common at all voltages above 11 kV.

2. CLASSIFICATION BASED ON APPLICATION

A Sub-station can be classified on the basic of functional requirement related with

applications. Some of the types include:

* Sub -Station in generating station receiving station, Distribution system.

* Factory Sub-stations.

* A.C / D.C conversion Sub-stations.

* Sub-station for Load center

CHAPTER 2.

LIGHTENING ARRESTAR

A lightning arrester is a device used on electrical power systems to protect the insulation on

The system from the damaging effect of lightning.

The most common device used for protection the power system against high

voltage surges is the surge diverter the incoming high voltage wave to earth such a divider

alternatively called as lightening arrester Fig Shows the basic form of a surge diverter. It consists

of a spark gap in series.

2.1 CONSTRUCTION

Series with a non linear arrester one end of the diverter it is connected to the terminal of

the equipment to be protected and other end effectively grounded. The length of the gap is so set

that normal line voltage is not enough to cause an across the gap but dangerously high voltage

will break down the air insulation and farm of an arc.

The property of non - linear resister is that resistance decrease as the voltage or

current increase and vice versa .this is clear forms the volt /amp characteristics of the resister

shown in fig.

Fig 2.1 lightening arrester

2.2 ACTION

The action of lightening arrester as surge diverter is as under.

1. Under normal condition the lightening arrester is off. The line i.e. It Conduct

no current to earth as the gap break down an arc is formed providing an arc low voltage

resistance path the surge to the ground in this way the excess charge on the line due to

surge is harmlessly connected through the arrester to the ground instead of being sent over the

line

2. It is worthwhile to mention the function of a liner Resister in the operation

of in the arrester. Since the characteristics of resistor are to offer high arrester .As the gap spares

over due to over voltage. The arc would be short resistors to high resistance to high voltage at

current It prevent the Surge is over the resistances high resistance to make the gap none

conducting.

2.3 TYPE OF LIGHTENING ARRESTER

There are several type lightening arrester in general use they differ are in construction

details but operate on same principle viz. production low resistance path has the surge to the

ground.

The fallowing lightening arrester is used.

1. Rod gap arrester.

2. Horn gap arrester.

3. Multi gap arrester.

4. Expulsion type lightening arrester.

5. Value type lightening arrester.

2.4 APPLICATION OF LIGHTING ARRESTER

the electrical terminal equipment installed at a sub-station are often subjected to over

voltages as high frequency line such traveling impulse waves are required to be diverted to

ground by providing lighting arresters at the termination of each transmission line. These surges

also get doubled as they are reflected from inductive termination elements like transformers

which have to be protected by providing lighting arresters. (Also known as the surge

arrester) close to the H.T and L.T bushings of the transformers. At 20K.V G.S.S madar the

220kv/ 132kv/ 33kv/ and 11kv high voltage lighting arresters are used.

CHAPTER 3.

POTENTIAL TRANSFORMER

P.T which step down the voltage at the system to sufficient low values is necessary an every

power system has-

1. Indicating of voltage conditions.

2. Metering of the supply exchange of energy.

3. Relaying and Synchronizing.

The P.T is employed for voltage above 380 volt to the potential coils of metering and

indicating instrument.

The primary winding of P.T is connected to the main bus bar of the switch-gear

installation and to the secondary winding. Various indicating and metering instruments are

connected. It is located between the C.T and isolators.

Fig 3.1 Potential Transformer

Fig 3.1.1 Potential Transformer

3.1 APPLICATION

P.T is used for the measurement and protection .Accordingly these are either

measuring protective type voltage transformer. They may be either signal phase or three phases.

Fig 3.1.2 basic diagram of Potential Transformer

3.2 SPECIFICATION

The following aspects are determined while selecting P.T.

1. Rated primary voltage

2. Rated secondary voltage

3. Rated burde : 1000VA

4. Supply Frequency : 50 HZ

5. Numbers of Phases : 3

6. Temperature Catg. : --10C TO 55C

7. Total Weight : 600 kg

est voltage : 460 kV

9. Voltage Factor : FOR 30 Sec.

CHAPTER 4.

CURRENT TRANSFORMER

Measuring of A.C are of most frequency operation not only because of its inherent but

also because it is necessary in determining parameters of electrical circuit a sample of current

is required for

1. for indicating and graphic commuters.

2. K.W.H. and K.W. meters

3. Telemeter and

4. Protective relay

A current transformer is intended to operate normally with the rated current of network.

Flowing through the primary winding which is inserts in series network. The secondary winding

of C.T connected to measuring instrument & relay supplies a current which is proptional to and

in phase with the current circulating error and phase displacement inherent in the design of C.T.

Fig 4.1 Current Transformer Fig 4.1.1 Current Transformer

4.1 CONSTRUCTION

The C.T. basically consists of core on which are wound a primary and one of two

secondary winding. The primary is directly inserted in power circuit (The circuit current is to be

measured) and to the secondary winding. The indicating and metering instruments are connected

when the rated current of C.T. flows through its primary winding, a current of 5 Amp. Will a par

in its secondary windings. The primary winding usually a singal turn winding and numbers of

turns as the secondary winding depend upon the power circuit to be measured

Fig 4.1.2 basic diagram of Current Transformer

4.2 SPECIFICATION OF C.T

1. Rated primary current

2. Rated secondary current

3. Rated exciting current

4. Rated Burden

5. Supply Freq.

6. Rated system volt

7. Insulation level

8. C.T Ratio

CHAPTER 5.

ISOLATORS

Isolators as disconnecting switch are used to upon same given part of a power circuit after

breaker. Thus isolator’s surges only have preventing the voltage from being applied to same

given section of bus. In a given insulation as to one as another piece of app-rates in the

insulations.

In same case isolator may be used as a circuit breaking device but their use for

this purpose is strictly limited by thereinafter condition such as then power rating of the given

circuit . These are two types of isolators.

1. Single pole Isolators.

2. Three pole Isolators.

Fig 5.1 Isolator

Isolators operate under no load condition. It does not have any specified current

breaking capacity or current making capacity. Isolators are not even used for breaking load

current. Isolators are used in addition C.B. isolators used in power system are generally 3 pole

isolators. The 3 pole isolators have three identical poles. Each pole consists of two or three

insulation parts mounted on a fabricated support. The conduction posts are supported on the

insulator posts. During opening operation the conduction rod swings and isolation is obtained.

The simultaneous operation of three poles is obtained by mechanical inter locking of the three

poles.

While opening:

1. Open C.B.

2. Open Isolator

3. close Earthling switch

While closing:

1. Close C.B.

2. Close Isolator

3. Open Earthling switch

5.1 CONSTRUCTION

The vertical pantograph type design is preferred for rated voltages of 420 K.V. and

above fig. Shows the single pole outline of a 245 K.V.1200Amp isolator. The blades do not twist

because of adopting reverse loop contact resulting in greatly simplified construction for this

reason inspection and maintenance are almost unnecessary and sure operation is provided with

small operating torque. The insulators are mounted on a galvanized rolled steel frame. .

The three poles are interred- locked by means of steel shaft. The common operating

mechanism is provided for all the three poles. Fig. shows one pole of a triple pole isolator in

closed Position.

CHAPTER 6.

CIRCUIT BREAKER

Circuit breaker plays an important role in the design and performance of a power system

is that these are the key piece of apparatus protecting. The system and that ensure the continuity

of supply from consideration of cost .The circuit breaker represents a Males them and is perhaps

next only to the generation and transformer.

A circuit breaker is piece equipment which can –

1. Make as break a circuit either manually as key by remote control under contrition.

2. Breaker a circuit automatically under fault condition.

3. Make a circuit either manually as by remote control fault conditions.

6.1 OPERATING PRINCIPLE

A circuit essentially consist of a fixed and moving contacts, called electrodes .Under

normal operating condition these contacts remain closed and will not open automatically unit

and unless the system becomes faulty. of course , the contact can be opened manually or by

remote control whenever desired When a fault occurs in any parts of the system , The trip coils

of the breaker get energized and the moving contact are pulled operate by same mechanism, thus

opening the circuit and oil from one chamber is prevented from mixing with the chamber.

Fig 6.1 Circuit Breaker

This arrangement permits two advantage firstly the circuit breaking chamber require a small

volume of the coil which is just enough for arc extinction secondly, the amount of oil to be

replaced is reduced as the oil in the supporting chamber does not get contaminated by the arc.

The annular disc and balkanized paper is employed for insulation purpose only.

6.1.2 OPERATION

Under normal operating condition the moving contact remains engaged with the upper

fixed contact. When a fault occurs, the moving contact is pulled down by the tripping and an arc

stack. The arc energy appraises the oil and produces gasses under high pressure. The action

constrains the oil pass through. The respectiv passages of the tabulator. The process of tabulation

is orderly one , which the section of the arc are successively quenched by the effect of

separate. Streams of the oil moving across each section in turn and bearing away its gasses.

6.1.3 ADVANTAGE

An M.O.C.B has the following advantage a bulk oil C.B

1. It require lesser than quantity of oil

2. It require smaller space

3. There is reduced risk of fire.

4. Maintains problem are reduced.

6.1.4 DISADVANTAGE

1. Due to smaller quantity of oil, the degree of carbonization increased.

2. There is a difficulty of remaining the gases.

3. The dielectric strength of oil detritus rapidly due to high degree of combinations.

6.2 AIR BLAST CIRCUIT BREAKER

Air blast circuit breaker is used to day from 11to 1100 K.V. for various applications.

They offer several advantage such as faster operation ,suitability for the repeated operation ,

Auto - recto sure , Unit type multi break construction , Simple assembly ,The Modest

maintenance , ect .A compressor plant in necessary to maintain high air pressure in the air

receiver .air blast circuit breaker are especially suitable for Railways not are furnaces where the

breaker operated repeatedly . Air-blast circuit breaker is used for interconnected lines and

important lines and important lines where Rapid operation is desired.

6.2.1 CONSTRUCTION OF AN AIR BLAST CIRCUIT BREAKER

In air blast circuit breaker high pressure air is forced on there are through a nozzle

at instant of contact separation. The Ionized medium between the contacts is blown away by the

blast of the air. After the arc extinction the chamber is filled with high pressur air, which prevents

restrict. In some low capacity circuit breaker.

Fig 6.2 Air blast circuit breaker Fig 6.2.1 Air blast circuit breaker

6.2.2 DESCRIPTION

High pressure air, at a pressure between 20 cm to 30 cm is stored in the Air

Reservoir. Air is taken from compressed Air system. The opening is fast because the air takes a

negligible time of travel from the Reservoir to the moving contact. They are extinguished within

a cycle. Air blast circuit breaker is very fast in breaking the current.

Closing the also fast because the pressure in the extinction hampers drops impeded

or the Air blast circuit breaker requires an auxiliary compressed air system. Air blast circuit

breaker for 12 Kv generally has a different type of construction.

Air blast circuit breaker is preferred for the Furnace Duty and action system,

because they are suitable for repeated duty. Whereas oil circuit breaker are not satisfactory for

such duties.

They capacitors are connected across the interrupter unit for the equal distribution

of voltage between the units .closing resistors are connected across the interrupter unit of limiting

the over voltage during closing operation. Opening resistors are connected across the interrupter

units to make the circuit breaker Restrict free.

Isolator is an integral part of the circuit breaker. The circuit breaker opens and immediately

after the Isolator opens, to provide additional gap.

6.2.3 PRINCIPLE OF AIR BLAST CIRCUIT BREAKER

The air blast circuit breaker needs an auxiliary compressed air system. Which

supplies air to the air receiver of the breaker? For opening operation the air is admitted in the

extinction chamber .It pushes away moving contacts. In doing so, the contact are separated and

the air blast takes away the Inside guess along with is and assists are extinction. After a few

cycles arc is extinguished by the air blast and the arc extinction chamber is filled with high

pressure air (30 kg/cm). The high pressure air has higher dielectric strength than that of

atmosphere pressure. Hence a small contact gap of few centimeters is enough.

In the axial blast type air C.B air flow the flow air is longitudinal along the arc. In

axial blast type air flow, the from high pressure Reservoirs the atmosphere through a convergent

divergent nozzle. The difference in pressure and desire of nozzle 13 such that as the air expands

into the low pressure zone. If attains almost supreme velocity. The mass flow of air through the

nozzle 13 grounded by the parameters like pressure ratio, area of throat diameter. and is

influenced by the diameter of the arc itself .The air flowing at a high speed axially along the are

causes Removal of heat from the periphery of the area and the diameter of the are Reduces to

a low value of current Zero. At this instant the area is interrupted and the contact space is flushed

with fresh air flowing through the nozzle.

6.3 VACCUM CIRCUIT BREAKERS (VCB)

In such breaker ,Vacuum is used as they are quenching superior are quenching

properties any other medium for example, when contacts of a breaker are opened in vacuum the

interruption, occurs of first current zero with deadener strength between the contacts building up

at a rate thousands times higher than that obtained with other circuit breaker.

6.3.1 PRINCIPLE

The production of arc in a vacuum circuit breaker and its extinction can be explained

as follows. When the contact of the breakers are opened in vacuum (10 to 10 ), and are is

produced between the contact by the ionization of metallic vapors, electrons and iron produced

during are rapidly condense on the surface of the breaker contacts, resulting in quick recovery of

dielectric strength. The reader may note the salient feature of vacuum as are quenching medium.

As soon as they are produced in vacuum, it is quickly extinguished due to the fast rate of

recovery of dielectric strength in vacuum.

Fig 6.3 vacuum circuit breaker

Fig 6.3.1 vacuum circuit breaker

6.3.2 CONSTRUCTION

Part of a typical vacuum circuit breaker. It consists of fixed contact, moving contact

and are should mounted inside a vacuum chamber. The movable member 13 connected to the

control mechanism by stainless steel bellows this enables the permanent sealing of the vacuum

chamber so as the eliminate the possibility of leak glass vessel or ceramic vessel 13 used as the

other insulating body. There are shield prevents the deterioration of the internal dielectric

strength by preventing metallic various falling on the inside surface of the outer insulating.

6.3.3 WORKING

When the breaker operates, the moving contact separates from the fixed contact and an

arc is truck between the contacts the production of arc is due to the ionization of metal is quickly

extinguished because the metallic vapors, electrons and ions produced during arc diffused in a

short time and seized by the surface of moving and fixed member shields since vacuum has a

very fast rate of recovery of dielectric strength, the extinction in vacuum breaker occurs with 9

short contact separation.

6.4 OIL CIRCUIT BREAKER

O.C.B’S are used at voltages 132 kV and below as at 220 kV size of C.B becomes

large and also modular construction is necessary for 36kv, 72.5 kV and 145 kV ratings O.C.B are

outdoor type with one interrupter per pole and single operating mechanism for three poles. In

O.C.B the current interruption tasks play inside interrupter. The enclosure of interrupter is made

of insulating material like porcelain. The oil from this chamber does not mix with that in the

lower chamber acts like a dielectric support. The operating rod is operated by operating

mechanism. The three poles operate mutinously. Above 36 kV the breaker pole compares two

parts a support insulator filled with dielectric oil and extinguished chamber mounted on the

support insulator.

6.4.1 SPECIFICATION OF OIL CIRCUIT BREAKER

1. Type : HLC 36/1000

2. Voltage Rating : 36 kV

3. Current Rating : 1000 amp

4. Frequency : 50 Hz

5. Breaking cap. : 12.5 KA

6. Coil Voltage : 220V DC

7. Auxiliary Volt : 415 V

7. Making Cap. : 31.2 KA

8. Short Time : 3 sec

6.5 SF6 GAS CIRCUIT BREAKER

The SF6 circuit breaker makes use of subpar Hexafluoride (SF6) gas which has

excellent arc quenching capability and exceptionally high electrical insulating cartelistic. In this

breaker the gas flow puffed by a puffer cylinder extinguishes the arc.

The simple principle makes the breaker operation very simple, with low breaking

noise. The pneumatic operating mechanism which is operated by air pressure for opening and

spring force for closing is very simple and reliable.

6.5.1 CONSTRUCTION

Construction of the breaker is broadly the breaker consist of a 3 pole units containing

puffer type interrupter housing comprising a pneumatic operating mechanism Construction of the

breaker is broadly the breaker consist of a 3 pole units containing puffer type interrupter housing

comprising a pneumatic operating mechanism and a compressor and a motor air reserve and a

horizontal rod assembly. opening operation is carried out a compressed air stored in the air

reservoir of approximately 15 kg/cm (231 psi) pressure indicated by air pressure gauge and

closing operation is accomplished by closing operation Each interrupting unit is filled with Sf6

gas and kept at same pressure same pressure through the interconnections copper gas pipe which

is also connected to the gas pressure switch and the bags feed port .All the moving contacts of the

three interrupting units are inter – linked mechanically the operating mechanism.

Fig 6.5.1 SF6 circuit Breaker

Fig 6.5 SF6 circuit breaker

6.5.2 PHYSICAL PROPERTIES OF SF6 GAS

1. Molecular weight - 146.07

2. Melting point - 50.7 c

3. Sublimation Temp - 63.8 c

4. Critical Temp - 45.547+0.003

5. Critical pressure - 38.55 kg/ cm

6. Critical Density - 0.730.g/cm

7. Dielectric constant - 1.002 at 25 c, 1 atm.

8. Thermal conductivity at: 3.36 10 ......30 c

9. Specific heat ratio - 1.07

10. Solubility in oil - 0.297......

CHAPTER 7.

BUS BARS

Bus bar term is used for a main bus as conductor caring electric current to which many

connections may be made. Bus bar is mainly commitment means of connecting switches and

other equipment in to various arrangements.

The usual arrangement of connection in most of sub-station permits working an

almost piece of equipment two buses are provided to which the incoming and outgoing Feeders

and the principle equipment may be connected one bus bar usually called “Main Bus’’ and other

‘auxiliary’ the main bus may have a more elaborate with it.

The bus bar is usually of aluminum and of rectangular gas section.

7.1 VARIOUS BUSBAR ARRANGEMENTS

1 Single bus bar

2 Single bus bar with bus sectionalized

3 Double bus bar

4 Double breaker Scheme

5 Main and transfer bus bar

6 Breaker and a half scheme

7 Double bus bar with bypass isolator

Mesh scheme bus bar coupler is used to couple and decouple two bus bar in a bus bar

arrangement.

CHAPTER. 8

INSULATOR

To prevent the flow of current to the earth form support to transmission line as distribution

line. One all secured to the supporting towers and poles with the help of insulator. Thus the

insulator plays an important role in the successful operation of the lines.

Principally the insulator are made of porcelain and steatite the later had the advantage of

very much higher tensile and bending strength compared with porcelain tightened glass is

another material which is some time is used for insulators.

8.1 TYPES OF INSULATOR

8.1.1 PIN INSULATOR

It is attached to a steel bolt pin which is secured to a cross arm on the pole the

conductor is supported in the given at top end and side of insulator. This types of insulator is

commonly employed for operating voltage up to about 25 KV Through two piece, three piece,

four piece insulator can be constructed for a working voltage respectively 45 H.V 66 K.V and

beyond 66 K.V.

Fig 8.1 Pin Type Insulator Fig 8.1.1 Pin Type Insulator

8.1.2 SUSPENSION INSULATOR

In the insulator the conductor need in a clamp which is the suspended from the

cross arm of tower by a string of use insulator units connected to each alder by metal link and

pins. There are three type insulators.

1. Hewlett suspension insulator

2. Cement cap insulator

3. Care and link type insulator

Fig 8.1.2 suspension insulator

8.1.3 STRAIN INSULATOR

Such type of insulator agreement to take gust of tension of conductor at line terminal

Fig 8.1.3 Strain insulator

And at point the line is dead ended.

CHAPTER 9.

POWER TRANSFORMER

A power transformer is used in sub-station to step up and step down the voltage. Except

at the transformer all the sub station use step down transformer to gradually reduce the voltage of

electric supply and finally deliver it at utilization voltage. The morden practice to use three

phase transformer in sub station. In such transformer load tap changing mechanism can be used.

The transformer is generally installed upon lengths of wall fixed on concrete.

Labs having foundation 1 to1.5M Depth far rating up to 10 moves. A naturally cooled oil

immersed transformer is used. For higher rating the transformer is used air blast cooled.

Fig 9.1 Power Transformer

9.1 TYPES OF POWER TRANSFORMER

According to construction of core and winding

A. core type

B. shell type

According to type of connection

a. Star-star

b. Delta-delta

c. Star-delta

d. Delta-star

According to type of cooling

a. Oil Natural Air Natural (O.N.A.N.)

b. Oil Natural Air Forced (O.N.A.F.)

c. Oil Forced Air Forced (O.F.A...F.)

d. Oil Forced Air Natural (O.F.A.N.)

e. Oil Forced Water Forced (O.F.W.F.)

f. Air Natural

9.2 INDICATOR APPARATUS

The indicating apparatus of power transformer are as below:

1. Oil gauge : To indicate the oil level in indicator

2. Temperature indicator: To indicate the temp of all and winding.

3. Pressure Gauge : To show the interval pressure of tank.

9.3 CORE AND FRAME

Core is used to produce a closing magnetic coupling between L.V and H.V winding.

Also to minimize leakage flux and to provide a low reluctance path for the flux.

Laminated core for transformer is made lamination of high silicon contents

containing 4silicon. On each lamination insulating varnish is coated. Core and assembly is done

by two methods by built joint method and by interleaved method.

9.4 TRANSFORMER WINDING

The low voltage and high voltage windings are fitted on the limbs by these input

voltage is stepped up as stepped down. Low voltage winding are nearer to the core. Winding are

made of insulated copper wires. Wires are insulating by supper annealed paper as cotton.

Each coil can again insulate by insulated paper by separately .in distribution and

power transformer two types transformer used.

1. Concentric

2. Interleaved

Each phase winding is separately placed on separately limbs. This winding is given rectangular

shape after construction of these winding are placed inside the oil tank of transformer

The winding are complete by dipped in oil. The winding are topped to control the number of

turns of H.V. windings by which transformer ratio is changed.

9.5 BUSHING

Transformer terminal bushing parodies insulation to the terminals of windings

coming out of tank and cannot them to deferent type of electrical system.

Transformer bushings are of different types and shapes which depend on the voltage

Power and on transformer where they are to be fitted. When high current flaws through

conducting rod of bushing a high magnetic field is produced between side cares and transformer

care which heat it. These are six bushing used three of incoming 33KBV and there are for

outgoing 11kv.

A Protective relay is a device that ducts the faults and initiates the operation of the

circuit breaker to isolate the defective element from rest of the system.

9.6 TAP CHANGER

Tap changer is a type of which by which high voltage turn number is changed by

changing the taping by are done to control the voltage. Tap changer are attached the care of

transformer and the channel as vertically along the wall of the transformer tank.

Tap changer has insulated laminated base plate shaft and handle. In insulated base

plate contacts are made with pressure. In shaft electrical moving contact are there and a lock is

there is there in handle. So that handle. So that handle may be stopped at desire position. On

insulated base plate stationary contact are there which tapping of undoing join. By rating handle

the moving contact with shaft are connected respectively to fixed contacts. Hence by this way

different transformer ratio can be obtained at different conditions.

9.6.1 ON-LOAD TAP CHANGER

The Tap changer, if dispatched separately, is to be fitted to the tank. The insulation

resistance value of each tap changer lead to earth should be measure and the cause of low values,

if any investigated, the leads from the tap changer should then be connected to their respective

position on the terminal board provided on the tank. The tightness of all connections of the

selector switch and terminal board should be ensuring. Any protective taping on the diverter

switch bushing is to be removed.

In transformer of large ratings the space above the oil in the vent is usually connected by a pipe

to the top of the conservator to equalize the pressure & vent it to the atmosphere through the

breather. For transformer supplied without equalizing pipe an air-cock is fitted at the top which

must be opened when the tank is being filled with oil and closed again.

9.7 CONSERVATOR

Oil immersed power transformer has a used and its causer in which level of increase in

transformer and vice versa. With this such facilities is provide that three must be minimum

contact of oil with air so that is may be safe from oxidation and moisture. Such tank is called

conservator.

Oil conservator is a circular and cylindrical steel drum with is attached horizontally

along the cover of the tank up to so to 70 mm so that directly all may be not came from

conservator to tank.

9.8 BUCHHOLZ RELAY

Buchholz relay gas activated relay insulated in oil immersed transformer for protection

against all kinds of protection against all kinds of faults. It is used to give an alarm in case of

incipient developing fault in the transformer and to disconnect to transformer from the supply In

the event of several internal faults. It is unusually installed in the pipe connecting the conservator

to the main tank. It is a universal practice to use buchholz relay on all such oil immerged

transformer housing rating in excess of 750 K.V.A.

9.8.1 OPERATION

The operation of buchholz relay is as follow.

1. In case of incipient fault with in the transformer the heat due to faults causes the

de-composition of the same transformer oil in the main tank the product of decomposition of

contain more than 70%of hydrogen gas. The hydrogen gas being light tries to go in to the

conservator & in the process gets entrapped in the upper part of relay chamber when a pre-

determined amount of gas get accumulated. It exerts sufficient pressure on the float to cause it to

till and close the contacts of mercury switch attached to it .This complete the alarm circuit to

sound an alarm.

2. It a serious faults occurs in the transformer and large amount of gas is generated in

the main tank .the oil in the main tank riches towards the conservator via the buchholz relay and

in doing so tills the float to close the contacts of mercury switch .This completes the trip circuit

to open the circuit breaker controlling the transformer.

9.8.2 CONSTRUCTION

Fig shows the constructional details of buchholz relay. It takes them from of a

dammed vessel placed in the connecting pipe between the main tank and conservator. The device

has two elements the upper element consist of a mercury type switch attached to a float. The

lower elements consist of contains a mercury switch mounted on hinged type located in the direct

path of the flow of oil from the transformer to the conservator. The upper elements close an

alarm circuit during incipient faults whereas the lower element is arranged to trip the circuit

breaker in case of internal faults.

9.8.3 ADVANTAGE

1. It is the simplest form of transformer protection.

2. It detects the incipient faults at a stage much easier then the possible with oater

Forms of protection.

9.8.4 DISADVANTAGE

1. It can only be used with oil immersed transformer equipped with conservator.

2. The device can detect only fault below all level in the transformer. Therefore

separate protection is needed for connecting cables.

The lower part as surface of breather from where air enters has an oil. According to

the amount of moisture present in the inner air (i.e. in the cell tank). The callus of the silica get

crystals changes cellar of the silica get crystals is finished. No change these as can be again used

after heat treatment.

Fig 9.2 Buchholz Relay

9.8.5 TANSFORMER OIL TESTING

Fig 9.8.5 transformer oil testing

We provide excellent transformer oil testing services through our experienced professionals.

We test the transformers on various crucial parameters such as:

Specific Resistance (Resistivity)

Dielectric Dissipation Factor (Tan Delta)

Neutralization Value (Acidity)

Sediment (Sludge)

Flash Point

Water Contents (PPM)

Inter facial Tension

Dielectric Strength (BDV)

Dissolved Gas Analysis

Density

CHAPTER 10.

EARTHING

Connecting of electrical equipment an apparatus the earth curie with of a connecting

wire of negligible resistance is known as Earthling as grounding.

There are two types of earthling-

1. Pipe earthling

2. Plate earthling

At the sub station rush earthling is provided.

Pipe earthling is the best earthling and very cheap in cost. In this method a galvanized

steel and perfect pipe of approved length & diameter is placed. The size of pipe diameter upon

the current to the carried and type of soil.

Licensee/utility/company shall draw standards for earth resistance of the GSS and shall

maintain record of measurement of earth resistively & earth resistance carried out before the

commissioning of Grid sub-station or lines of above 33KV voltage or each earthed structure of

33 KV and lower voltage lines.

The periodicity for me measurement of earth resistance will be as specified below:

Each manned sub-station/guarding : once every year

Other sub-station/line towers : 5% randomly selected locations every year

Earthling resistance shall be measured with reference to other electrode/earthman at a

distance at least 10 times the height or length or depth of the earthling rode/electrode/earthman.

For such measurement, lead resistance will be subtracted.

CHAPTER 11.

CONTROL – ROOM

Control room is used to control the working the battery the battery room, compressor

room and electrical instrument and protecting devices present in the yard of the G.S.S.

There are four main sets of panels in the control room

1. 220kV panel set

2. 132kV panel set

3. 33kV panel set

4. 11kV panel set

Different panels of different circuit breaker, Transformer, Lightning Arresters, Isolators,

Current Transformer, and Potential Transformer P.L.LC etc. are coming to the control room. In

each sets of panel there are at least over current and one earth fault relay. From control panel the

operate can know what is happing in the sub station yard the operator can control, start,

regulate or switch off the main circuit from control panels. In substation the control and relaying

equipment is installed in control room.

The diagram of main connections are given in the front face of the panel there diagrams

indicate the position of the C.B. and Isolators. The controls operate get the idea as to which

breaker is open as closed. In medium installation and panels which can be increased to

accommodate relay and other equipment. In case complex protective scheme a separate relay

panel is necessary.

Fig 11.1 Control Room

CHAPTER 12.

D.C SYSTEM

1 (+) Plate: - It consists of lead bromide Pbo2 deposited on the grid farm.

2. (-) Plate: - It consists of porous. Sponge of lead deposited on a grid frame an antimony

lead allows similar to that (+) plate.

3. Separator: - Its function to keep the +vet & -vet plate electrically part. It consists of a

thin sheet of canon conducting porous material.

4. Container: - It is made of hard rubber it is a box in which assembly is kept.

5. Electrolyte:-It is dilute H2SO4 acid containing 31% acid by weight & 21 % by volume

the specific gravity of electrolyte is 1.23 at 27c

6. Connector:-The Function of connector is to connect two battery in series in a battery

tank, it is made of thick CU strip, specify gravity condition of Battery.

22 to 1.23 100% charged

1.2 to 1.21 75% charged

1.75 to 1.85 60% charged

1.15 to 1.16 25% charged

Less than 1.15 DISCHARGED

12.1 BATTERY CHARGING

Discharged Battery burg charged by a battery charger. There are two battery charger

one for 110V Battery & Other for 220V Battery .The different Methods are available for

charging of battery such as.

(1) Trickle charging

(2) Float charging

(3) Boost charging

(4) Const. voltage charging

(5) Const. current charging

Pb+Pbo2+2H2SO4 +2Pbso4+2H2O

1. Float charging- Cell can be float by keeping charge at different voltage such as 2.1V all

Battery slowly discharge itself, must be charge fortnight 2.15-2.25 V per cell. Very small flow

current requiring Battery to be overcharged once in two month.

2. Trickle charging: - 2.25 to 223 V per cell - This is done with trickle current of over 1 Mill

amp of nominal capacity of cell & current should be adjusted by actually monitoring system.

3. Boost charging: - During winding, condition some time we require extra charge, so for this

purpose the Battery is charged Simultaneous with loading condition.

4. Civilization charging: - For improving the performance & life of the battery, the battery

charged regularly with a slow rate of charging with battery is unloaded.

CHAPTER 13.

COMPRESSOR ROOM

Compressor Room is used to provide compressed air. Air-Blast C.B in the order to

make up compressed air and pressure of 30 kg/cm compressor room is consisting of compressor

motor.

Air dryer two compressed air cylinders and reduces. As shown in diagram compressed air

from compressor motor goes to air dryer. In air dryer moisture get separated and released through

an automatic drain valve. Then air passes through filter where other dust particles and impurities

get filtered. There is a non-return valve which controls the flow of compressed air.

Now it passes through absorbs bed where compound impurities separate out. Then this

compressed air passes through artifice plate. There is a contact manometer range 0-100 kg/cm.

This moisture free compressed air of 60 kg/cm pressure supply to the two outside cylinder

providing with safety valve. In the end air passes to the reduces which reduced the pressure

of compressed air . This reduced compressed air of pressure 30 kg/cm is supply to the ABCB

with the help of pipes and 30 kg/cm pressure is maintenance in the air blast circuit breaker.

CHAPTER 14.

POWER LINE CARRIER COMMUNICATION SYSTEM

Power line carrier communication system differs in the method of calling. The

power supply or in the modulation system. Each end of the power line is provided with identical

carrier equipment consisting of transmitter, receiver, line tuning unit, master oscillator; power

amplifier etc. brief illustration of P.L.C.C. system is given in the section.

14.1 COUPLING CAPACITOR

The carrier equipment is connected to the transmission line through coupling capacitor

which is of such a capacitance that is offers low reactance (1/we) to carrier frequency but high

reactance to power frequency.

Coupling capacitor allows carrier signals to enter the equipment but does allow 50 Hz power

frequency to enter the carrier equipment

14.2 LINE TRAP UNIT

Line trap unit is inserted between bus bar and connection of coupling capacitor to the line.

It is parallel tuned circuit comprising L & C .It has a low impedance to 50 Hz and high

impedance to carrier frequencies. This unit prevents the high frequency signals from entering the

neighboring line and the carrier current flows. Only in the protected line.

14.3 PROTECTION & EARTHING OF COUPLING CAPACITOR

Over voltage on power line are caused by lighting, switching, faults etc. produce stress on

coupling equipment & line trap unit. On liner resistor in series with a protective gap is connected

across the line trap unit & the inductor of line trap .the gap is set to spark at a set value of over

voltage. Base of coupling unit is earthed by earth rod in the vicinity to obtain low earth

resistance.

14.4 ELECTRONIC EQUIPMENTS

There are generally identical units at each end

1. Transmitter unit

2. Receiver unit

3. Relay unit

14.4.1 TRANSMITTER UNIT

Frequencies between 50 to 50 kHz are employed in different frequency bands. Each band

has certain bandwidth. Carrier frequencies are generated in oscillator. It can tune to a particular

frequency.

The output of the oscillator is fed into the amplifier to overcome the losses in

transmission path between the transmitter & receiver at remote end of line.

14.4.2 RECEIVING UNIT

The high frequency signals arriving from remote end are received by receiver. The

receiver receives the signals and feeds to carrier relay unit. Receiver unit comprises (1) an

attenuator, which reduces the signals to a safe value. (2) Band pass filter which restricts the

acceptance of unwanted signal. (3) Matching transformer to match the impedance of line &

receiving unit

Fig 14.1 Wave Trap

14.5 ADVANTAGE OF P.L.C.C.

No separate wires are needed for communication purpose, as the power lines

themselves carry power as well as communication signals. Hence the cost of constructing

separate telephone line is saved.

1) When compared with ordinary lines the power lines have appreciable higher mechanical

strength. They would normally remain unaffected under the conditions which might

seriously damage telephone lines.

2) Power lines usually provided the shortest route between the power station. Power lines

have large cross sectional areas resulting in very low resistance per unit length.

Consequently the carrier signals suffer much less attenuation than when they travel on

usual telephone lines of equal lengths.

CHAPTER 15. RELAYS

Relays are the devices that detect abnormal conditions in electrical circuits by constantly

measuring electrical quantities, which are different under normal and fault conditions. The basic

electrical quantities, which may change under fault conditions, are voltage, current, phase angle

and frequency. Having detected the faults the relays operates to competent the trip circuit which

result in opening of the circuits breaker and therefore in the disconnection of the faulty circuits.

15.1 TYPES OF RELAYS USED IN G.S.S.

a) Over – current relay

b) Differential relay

c) Earth fault relay

d) Distance relay

15.1.1 OVER CURRENT RELAY:

Directional type over current relays works on the induction principles and initiate

corrective measures when current in the circuit. Exceed the pre-determined value. The

actuating source is a current in the circuit supplied to the relay from a current transformer.

These relays are used on arc. Circuits and can operate for fault flow in either direction.

15.1.2 DISTANCE RELAY:

Distance protection is the name given to the protection, whose action depends upon the

distance of the feeding point to the fault. The time of operation of such a protection is a function

of the ratio of voltage and current, i.e. impedance. This impedance between the relay and the

fault is dependent upon the electrical distance between them. An impedance relay has an

operating force proportional to the fault current and restraining force proportional to the line

voltage at the relay. As soon as the ratio of this voltage to the fault current change i.e. falls below

a certain value, the relay operates. This value is dependent upon the distance of the fault, which is

predetermined. Hence for this reason the relay is discriminative and it does not operate for any

fault occurring outside this distance. As it is very important to localize the fault, a relay of the

above type is given a controlled time lag, so that the relay nearest to the fault operates first.

Again, the time lag characteristic is inversely proportional to the fault current that is passing

through the relay. In case of a fault, there is a steady fall of voltage along the line from the

feeding point to the fault. This voltage gradient can be utilized for longer be in balance. This

voltage difference will cause a current to flow through the operating coil of relay, which closes

the trip circuit.

15.1.3 DIFFERENTIAL RELAY:

A differential relay is one that operates when the difference of two or more electrical

Quantities exceed a predetermined value. There are two fundamental system of differential

protection viz.

1) Current balance protection

2) Voltage balance protection

A current balance differential relay is one that compares the current entering a section

Of the system of the system with the current leaving the section. Under normal operating

Condition no longer applies. If this differential current is equal to or greater than the pickup

value, the relay will operate & open the circuit breaker to isolate the faulty section.

Under healthy condition equal current flows in both primary windings. Therefore the

Secondary voltages are balanced against each other & no current will through the relay operating

coil.

15.1.4 EARTH FAULT RELAY:

Directional type over current relays work on the induction principle and initiates the

Char-active measures. When current in the circuit exceeds the predetermined values. The

actuating source is a current in the circuit supplied to the relay from a CT. these relays are

unsuitable for use as directional protective relays under short-circuit conditions. When a short

circuit occurs, the system values falls to a low value and there may be insufficient torque

developed in the relay to cause its operation. This difficult is overcome in the directional over

current relay, which is designed to be almost independent of system voltage and power factor.

CHAPTER 16.

CAPACITIVE BANK

The capacitor gives following functions

1 Voltage Rise

2 Energy storage

3 Power Factor Improvement

Generally it has 2 components-

Series reactor

Residual voltage transformer

SERIES REACTOR

During parallel operation of capacitor bank, it is necessary to limit inrush current to a

safe limit. Depending upon circuit breaker capability, this is done by series reactor. It provides

additional inductance in circuit.

RESIDUAL VOLTAGE TRANSFORMER

It provides protection to capacitor bank & for speedy discharge of it. RVT is connected

across capacitor bank. It has dual secondary winding. One for metering and another for

protection.

Fig 16.1 Residual voltage transformer

CHAPTER 17.

SAFETY MEASURES

Safety of consumers & maintenance staff from hazard of electrical shock.

Earthling of non-current part from the pt. Of view of safety of personnel.

Use of insulated shoes and gloves.

Use of rubber mats in control rooms.

Yard must be laid with stone gravel layer of 100 -150mm thick.

The equipments installed in G.S.S. must be regularly checked.

Shrubs, grass &. Trees etc should not be allowed to developing in the yard.

The fences must be checked.

Proper maintenance of each equipment in the G.S.S.

Electrical checking of PRD buchholz relay, OLTC surge relay & replacement of the gaskets

of the boxes.

IR measurement of winding

Tightening of nuts, bolts, clamps, fixtures, etc.

Checking of arcing horn gap-setting on bushing

Checking of oil level

Checking of alarm/indicator circuit & control & relay armlet wiring.

Checking of air/SF6 leakage.

Checking/cleaning of air filters.

Tightening of jumpers and bus connection.

CHAPTER 18.

CONCLUSION

The practical training at 220 kV G.S.S. Madar Ajmer has proved to be quite faithful. It

proved an opportunity for encounter with such huge components like Transformers, Circuit Breaker,

C.T. P.T., and switchyards etc. The architecture of the GSS (Grid Sub Station).

The way various units are linked and the way working of whole plant is controlled make the

students realize that engineering is not just learning the structure description and working of various

machines, but the greater part is of planning, proper management.

But there are few factors that require special mention. Training is not carried out into its tree

spirit. It is recommended that there should be some projects specially meant for students where the

presence of authorities should be ensured. There should be strict monitoring of the performance of

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

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

exposure of the practical implementation to theoretical fundamental.

CHAPTER 19

REFERENCES

I have undergone the training at 220KV G.S.S. MADAR, AJMER.I am highly grateful to

our training Co-coordinator Mr. M.K.JARWAL (XEN) and Mr. P.C. TIWARI (AEN.) to give me

guidance during training period.

1. An introduction to 220 kV GSS, Rajasthan Rajya Vidhut Prasaran Nigam Limited.

2. http:// www. Rvpnl.com

3. An introduction to transmission lines, A. Chakrabarti; Dhanpat rai & co., Delhi

4. An introduction to Electrical machinery, J.B. GUPTA.