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INDEX
S.NO. TOPIC
1. INTRODUCTION
2. THE YARD
3. LIGHTINING ARRESTOR 4. WAVE TRAP 5. ISOLATOR 6. INSTRUMENT TRANSFORMER 7. POTENTIAL TRANSFORMER 8. CURRENT TRANSFORMER 9. POWER TRANSFORMER 10. INSULATOR 11. CIRCUIT BREAKER 12. EARTHING 13. POWER LINE CARRIER COMMUNICATION 14. PROTECTION RELAY 15. CONTROL ROOM 16.BATTERY ROOM
17. CONCLUSION
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ACKNOWLEDGEMENT
This is my first practical training which has taken at 220 KV GSS, Sanganer.
I would like to express my sincere thanks to Ms. Tarannum Khan , Who
have given his excellent guidance and shared his experience with me using en-
tire course of this training report.
We are thanks to other staff member which are guided me. Finally I would
like to say this summer training has been a valuable part in my life.
At last but not least I am thankful to the all the staff member of
“YAGYAVALKYA INSTITUTE OF TECHNOLOGY”, department of Electri-
cal Engineering.
Pawan Kumar Gupta
B.TECH. IV YEAR (EE)
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PREFACE
This is training of 30 days my training place was 220 KV ,GSS, San-
ganer, Jaipur (rajasthan). GSS is the mean of connection between generat-
ing station and consumer by providing safety and reliability of system in case of
default.
This sub station step down the incoming voltage power transmission to the
required valve and then is supplied to the consumer feeder or GSS done by
connecting auto transformer operation and requirement of various equipment
have been include in detail , further in case of report is the bus bar.
Arrangement of different feeder level and switch yards included informa-
tion of bus bar arrangement of different level isolator and growing substation
also power transformer circuit breaker oil, filtration plant, and compression pro-
tection control room and place are leveled.
3
CHAPTER-1
INTRODUCTION
When India becomes independent its overall installed capacity was hardly
1900 mw. During first year plan (1951-1956) this capacity was only 2300 mw.
The contribution of Rajasthan state was negligible during 1&2 year plans the
emphases was on industrialization for that end it was considered to make the
system of the country reliable. Therefore Rajasthan state electricity board came
into existence in July 1957.
In India electrical power is generated at a voltage of 11KV to 33 KV .
which is taken stepped up to the transmission level in the range of 66 KV to
400 KV
Member of transmission and switching have to be created. These are
known as “SUB STATION”.
Along these transmission lines secondary substation are created where volt-
age is further stepped down to sub transmission and primary distribution volt-
age.
A substation is an assembly of apparatus, which transform the characteristics
of electrical energy from one form to another say from one voltage level to an-
other level. Hence a substation is an intermediate link between the generating
station and consumer.
For economic transmission the voltage should be high so it is necessary to
step up the generated voltage for transmission and step down transmitted volt-
age for distribution. For this purpose substations are installed. The
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normal voltages for transmission are 400kv, 220kv, 132kv and for distribution
33kv, 11kv etc.
Electricity boards are setup in all states of India which are responsible for
1. Generation
2. Transmission
3. Distribution
They also construct, install and maintain all the station made for these pur-
pose. In Rajasthan ,R.R.V.P.N.L. is responsible for transmission and distribu-
tion of electrical power all over Rajasthan. It has its own generating station and
it’s also gets power from various other stations also. It gets power from follow-
ing stations:-
1. Badarpur Thermal Power Station Delhi
2. Bhakara Nangl Project (at satlaj in Punjab)
3. Gandhi Sagar Dam Kota
4. Jawahar Dam Kota
5. Rana Pratap Sagar Dam Kota
6. Rajasthan Atomic Power Plant (RAPP) Kota
7. Kota Super Thermal Power Station (KSTPS) Kota
8. Anta Gas Power Plant Anta
9. Rajasthan share in Bhakara Beas Management Board (BBMB)
Power obtain from these stations is transmitted all over Rajasthan with the
help of grid stations. Depending on the purpose, substations may be classified
as:-
1. Step up substation
2. Primary grid substation
3. Secondary substation
4. Distribution substation
5. Bulky supply and industrial substation
6. Mining substation
5
7. Mobile substation
8. Cinematograph substation
Depending on constructional feature substation are classified as:-
1. Outdoor type
2. Indoor type
3. Basement or Underground type
4. Pole mounting open or kilos type
Any substation has many types of civil and electrical works. Main compo
nents are:-
Bus bar
Power transformers
Isolators
Circuit breaker
Lightening arrester
Insulators
Instrument transformers
The control room is equipped with protective relays, ammeters, voltmeters,
energy meters and frequency and power factor meters
D.C. supply is heart of GSS batteries are used for this purpose. They have
separate charging circuit also. For communication purpose P.L.C.C. is used
which has its various components.
220 KV GSS, Sanganer is the part of the transmission system.
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INCOMING FEEDER:
400 KV Heerapura- Sanganer,
220 KV Kota –Sanganer
220 KV Heerapura-Sanganer
OUTGOING FEEDER:-
132 K.V.
1. Balawala
2. Heerapura
3. Mansrovar
4. SMS Stadium
5. Chaksu
6. Sitapura
33 K.V.
1. Durgapura I & II
2. Sanganer
3. Sitapura
4. Muhana Mandi
5. Malpura Gate
6. Vatika
7. Phagi
8. IOC
11 K.V.
1. Tajawal
2. muhana
3. Prem Nagar
4. Industrial
CHAPTER-2
7
THE YARD The yard is spread in very long area. The yard of 220 KV GSS at Sanganer
has various equipment installed at the yard of 220 KV GSS, Sanganer are:-
Lighting Arrester
Wave Trap
Current Transformer
Circuit Breaker
Bus Bars
Power Transformer
Insulator
Potential Transformer
Static earthling system
PLCC equipment including coupling capacitance
Bushing
Isolator
Figure-2.1 Switch Yard
BUS BAR SYSTEM
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This bus bar arrangement is very useful for working purpose as every GSS.
It is a conductor to which a number of cut .Are connected in 220 KV GSS there
are two bus running parallel to the each other, one is main and another is auxil-
iary bus is only for stand by, in case of failure of one we can keep the supply
continues.
If more loads are coming at the GSS then we can disconnect any feeder
through circuit breaker which is connected to the bus bar. This remaining all the
feeders will be in running position .if we want to work with any human damage.
In this case all the feeders will be on conditions.
According to bus voltage the material is used .Al is used because of the
property & features and it is cheap.
With the help of bus bar arrangement we can connect all the incoming sup-
ply which is coming from different higher order GSS.
9
LIGHTEN - ING AR-
RESTER
Lightening arrester is first
equipment of GSS. It is pro-
tecting all the equipment
against the HV. The ground wire
or earthing does not provide pro-
tection against the high voltage
waves reaching the terminal
equipment .so some protective
device is neces- sary to produce
power station ,sub-sta-
tion and trans- mission lines
against the high voltage wave
reaching here. Which is connected between line and earth it acts as a safty
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PROPERTIES
COPPER ALUMINIUM
1. Electricity resistively at 20 c
0.017241
0.00403
2. Temp coff. Of resistively
0.00411
0.00403
3. Softening tem.
200
180
4. Thermal conductivity
.932
.503
5. Meting point
1083
657
valve. .
Through the surge impedence of line limits the amplitude of the line to
earth over voltage to a value which wills safe guard the insulation of the pro-
tected equipment.
An ideal L.A should have following characteristics:-
1. It should not take any current under normal condition .i.e. its spark
over voltage must be higher then the system voltage.
2. Any abnormal transient voltage above the break down voltage must
caused it to break as quick as possible in order to provide an alternate path to
earth.
3. It must be able to carry the resultant discharge current without
causing damage to itself.
For high voltage system the thirties type L.A are used .The value type is
also known as non linear diverter .These arrester consist of a spark gape and a
non linear resistance. Both resistance and spark gape are accommodated in se-
ries with a completely light porcelain condition humidity etc.
SPARK GAPE:-
They include a number of identical elements connected in series .Each ele-
ment consist of with pre ionization device between each grounding resistance of
high ohmic value connected in parallel.
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3.3 NON LINEAR RESISTER:-
The resister disc comprises inorganic material having a silicon carbide base
in a clay board. These discs form a block. The ohmic value of which decreases
rapidly when the applied voltage and current increases as soon as the current
wave resulting from the over voltage has been discharged. The resister block
subjected to the sole. Alternating Voltage and resistance assumes great
value .So that the amplitude of the resulting current becomes zero.
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Figure-3.1 Lighting Arresters
WAVE TRAP
It is used to trap the communication signals & send PLCC room through
CVT.
Rejection filters are known as the line traps consisting of a parallel resonant
circuit ( L and C in parallel) tuned to the carrier frequency are connected in se-
ries at each and of the protected line such a circuit offer high impedance to the
flow of carrier frequency current thus preventing the dissipation. The carrier
current used for PLC Communication have to be prevented from entering the
power equipments such as attenuation or even complete loss of communication
signals. For this purpose wave trap or line trap are used between transmission
line and power station equipment to-
Avoid carrier power dissipation in the power plant reduce cross talks with
other PLC Circuits connected to the same power station.
Ensure proper operating conditions and signal levels at the PLC transmit re-
ceive equipment irrespective of switching conditions of the power circuit and
13
equipments in the stations.
Line Matching Filter & Protective Equipments
For matching the transmitter and receiver unit to coupling capacitor and power
line matching filters are provided. These flitters normally have air corral trans-
formers with capacitor assumed.
The matching transformer is insulated for 7-10 KV between the two windings
and perform two functions. Firstly, it isolates the communication equipment
from the power line. Secondly, it serves to match .
Figure-4.1 Line Matching Filter & Protective Equipments
Transmitter
The transmitter consists of an oscillator and a amplifier. The oscillator gener-
ates a frequency signal with in 50 to 500 HZ frequency bands the transmitter is
provided so that it modulates the carrier with protective signal. The modulation
14
process usually involves taking one half cycle of 50 HZ signal and using this to
create block to carrier.
Receivers
The receivers usually consist of and alternate matching transformer band
pass filter and amplifier detector.
The amplifier detector converts a small incoming signal in to a signal capa-
ble of operating a relatively intensive carrier receiver relay. The transmitter and
receiver at the two ends of protected each corresponds to local as far as trans-
mitting.
ISOLATOR :-
When carrying out inspection or maintains work in substation ,it is essential
to disconnect reliability the unit of other station on which the work is done from
all other parts on installation in order to ensure full safety of working staff .So
guard against mistake it is desirable that should be done by an apparatus is
called “ISOLATOR”. In other words a device which is used to open or close the
circuit either when negligible current is interrupted or when no significant
change in voltage across the terminal of each pole of the isolator will result
from operation .they must only be opened or closed when current is zero. There
is single ear thing Isolator used .
Isolator is switching device used to open (or close) a circuit either when a
negligible current exists or when no significant change in voltage across the ter-
minal of each pole of the isolator, will result from the operation.
15
Broadly speaking isolator are the switches which’s operate under "No cur-
rent” condition. Thus, isolator is an apparatus which makes a visible and reli-
able disconnection of the unit or the section after opening the circuit breaker.
Isolators are file with earthing blades as an integral part of it. They may be
isolators with single ear thing blades or two earthling blades on either side of it.
The isolators used at 220 KV GSS, Sanganer have single earthing blades either
side of it.They must only be opened or closed when current is zero. Isolators are
classified into following categories.
1. Bus isolator
2. Line isolator
3. Transformer isolating switch
From constructional point of view the isolator may be classified as-
1.The post- centre post rotating part, double post break type.
2.Two post single type.
3.Base: - Each pipe phase isolator is mounted on a robust base of steal construc-
tion.
16
Figure- 5.1 Isolator
MOUNTING: -
The central post rotates in gun metal bushing and tapered roller bearing pro-
vided with grease nipples for lubrication required to be alone at regular’s inter-
vals during routine check up.
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EARTH SWITCH :-
(For line side insulation only ) Earthling is achieved by means of an earthed
blade pivoted at the base steady operation mechanism .the earth contacts are
fixed either at the back or left or right side of main contact and interlocked with
them by mechanism interlock.
OPERATING MECHANISM:-
1.Hand operated: - It consists of a fulcrums and level system for easy operation
of isolators.
2.The isolators used in G.S.S Sanganer at are three post types. Each isolator has
three insulators post per phase mounted on a phase of steal construction.
INSTRUMENT TRANSFORMER
The transformers which are used in A.C. system for the measurement of current,
voltage, power and energy are called Instrument transformer. These are also
used in connection with the measurement of power factor, frequency and for in-
dication of synchronism.They are two types namely:
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1.Current transformer
2.Potential transformer.
Figure-7.1 POWER X-MER
(1) Core type
(2) Shell type
The x-mer used substation is auto-transformer which employed only single
winding per- phase. A part of winding is common to both of sides. In addition
to primary and secondary winding known as tertiary winding is also provided
19
the power transformer required at substations contain following additional part
–
1. HV winding bushing
2. LV winding bushing
3. Tertiary winding bushing
4. Jucking plate
Transformer used in conjunction with measuring are ‘INSTRUMENT
TRANSFORMER’. According to the quality measured. These may be di-
vided as
1. Current transformer
2 Potential transformer
20
These instrument transformers are used to step down these current and voltage.
So that they would be metered with instrument of moderate size.
CURRENT TRANSFORMER
The current transformers are kept in the category of the instrument trans-
former. The C.T. are used to reduce/ stepping down A.C form high value to
lower value for measurement / protection / control.
21
They are usually installed in the out door switch. The primary conductor at
high voltage with respect to earth. The secondary of C.T. is just like the ring
type C.T. the primary winding consists of a very few turns , and therefore there
is no. appreciation volt drop across injection . Current is transformed by C.T.
the current transformer is used with primary winding , connected in series with
the line carrying the current to be measured and therefore primary current is de-
pendent upon load connected in the system.
Measurement of alternating current is one of the most frequent operation not
only because of it’s inheriant but a also because it is necessary in determining
other parameters of electrical circuit. A current transformer value of current is
used for Indication of current kwh and kw meters Telementry Protective relay
etc
A current transformer is intended to operate normally with rated current of
the system flowing through the primary winding which is increased in the series
with the network .Secondary winding of current transformer Connected to mea-
suring instruments and relay supplies currents circulating in the design of cur-
rent transformer.
22
POTENTIAL TRNASFORMER
Similar to CT it is another type of instrument type of instrument
transformer .Transformer used for voltage measurements are called voltage
transformer or Potential transformer. it may be of 1 phase or 3
phase
These transformers make the instruments suitable for measurement of high
voltage and isolating then from high voltage. these transformer are connected in
parallel and secondary winding is always open ckt.
The primary winding of the potential transformer is connected to the main
GSS LINE DIAGRAM. the primary has large no of turn in secondary,which
provided step down of voltage , and then the voltmeter is connected across sec-
ondary terminal the high voltage line.
Some terms related to PT :-
A. RATED VOLTAGE :- the capacity voltage of the PT
which it can stand
B. RATED TRARNSFORMER RATIO:- The ratio of the rated
primary voltage to the rated second voltage.
C. RATED SECONDARY VOLTAGE:- 130 / root (3) = 63.3
VAR.
Voltage transformer which step down system voltage to sufficient form
high value to low value are necessary in every system for