abstract
TRANSCRIPT
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.