1. HIMACHAL PRADESH STATE ELECTRICITY BOARD LTD.
220 kV GRID SUBSTATION
JASSUR , KANGRA (H.P.)
Prepared by:
Rupesh Mankotia
245/09
5th semester

2. INTRODUCTION
About substation
The substation in Jassur is one of the largest power capacity grid substation in H. P. .
It has installed capacity of 220kV , which is taken from three feeders.
1.) Pong dam ) Baira Suel ) Ranjit Sagar Dam / Thein dam
This 220 kV is step down to 132 kV, 33kV ,11 kV and distributed to nearby areas.
Instruments like circuit breakers , lightning arresters , wave traps , bus bars ,instrument transformers are used.

3. SALIENT FEATURES OF GRID SUBSTATION , JASSUR
Installed capacity of substation MVA
Transmission line feeding substation - 220kV AC
Brief specification of a transformer
1No. 25/31.5MVA  /33KV  Phase power transformer
4No. 40/50MVA  /132KV  Phase power transformer
1 No. 10 MVA No. 5 MVA  33/11KV  3Phase power transformer
 Types of breakers –
220kV SF6 gas circuit breaker
132kV SF6 gas circuit breaker
33kV minimum oil circuit breaker
11kV vacuum circuit breaker
Number of 132kV out going bays - 4
Number of 33kV out going bays - 6
Number of 11kV out going bays – 8
Area fed from substation – Nurpur , Jawali , Indora , (Kangra) and whole of distt Chamba

4. POWER LINE CARRIER COMMUNICATION
used for telecommunication ,telemonitoring between electrical substations , through power lines at high voltages
uses amplitude modulation technique
Capacitor Voltage Transformer are used for PLCC
transmit communication signal and 50/60 Hz power signal through same electric power cable
SLDC (State Load Dispatch Center ) get information by using PLCC communication

5. WAVE TRAP connected in series with the power transmission line
It blocks carrier frequency/waves (24 kHz to 500 kHz) on line
It allows power waves (50-60 Hz) to pass through it.

6. LIGHTNING ARRESTERS
It is a device used to protect the electric system from damaging effects of lightning.
lightning surge travels down the power system to the arrester
This surge current diverted around the protected insulation to earth.

7. INSTRUMENT TRANSFORMER
CURRENT TRANSFORMER
POTENTIAL TRANSFORMER

8. CURRENT TRANSFORMER
used for measurement of electric currents.
CT produces a reduced current accurately proportional to the current in the circuit
isolates the measuring instrument from high voltage circuit.
used in metering and protective relays.

9. POTENTIAL TRANSFORMER
are used to step down the voltage for:
Measurement
Protection
Control
allows protective relay equipment and measuring instruments to be operated at a lower voltages.

10. Circuit breaker An automatically operated switch
protect an electrical circuit from overload and short circuit
It is an on – load device
Classified as:
Low voltage circuit breaker
High voltage circuit breaker
Miniature circuit breaker
( an example of low voltage circuit breaker)

11. Gas circuit breaker (SF6 )
have excellent dielectric and arc quenching properties
arc is cooled by a gas blast of sufficient intensity
excellent thermal stability
100 times more effective than air in quenching arcing
SF6 circuit breaker is more efficient and reliable.
SF6 ( Sulphur Hexafluoride) circuit breaker at 132 kV side in Jassur grid substation

12. Vacuum Circuit Breaker
two electrical contacts are enclosed in a vacuum
One of the contacts is fixed, other is movable
during fault movable contact pulls away from the fixed contact, thus interrupting the current
are very durable
designed to last for an extended period of time. 
Vacuum circuit breaker used for 11 kV distribution
at Jassur grid substation

13. Isolator
used to completely de-energise the circuit for service or maintenance
have provisions for a padlock 
an isolator is an off-load device  .

14. Battery Bank Dc supply is necessary for the operation of the relays
The battery bank used in this substation is of 220V
110 cells is connected in series each of 2V
A number of batteries connected in series

15. 220 /33 kV 25/31.5 MVA transformer no. 1 at jassur substation
BUCHHOLTZ RELAY
BUSHINGS
CONSERVATOR
TRANSFORMER TANK
BREATHER

16. Transformer Tank
whole assembly of a transformer is placed in a metal sheet tank
assembly of the transformer is immersed in an oil which act as an insulator as well as coolant.
The oil will take out the heat produced by the transformer windings and core

17. Conservator
A cylindrical shaped air tight metal drum placed on a transformer tank
It provide cooling to transformer
It provide insulation between transformer windings.
Both OLTC (on load tap changer) and main tank’s oil are separated to avoid mixing of their oils

18. Breather apparatus with which breathing of the transformer takes place
SILICA GEL (DRY)
apparatus with which breathing of the transformer takes place
Oil is used to trap the dust particles , during contraction of oil & suction of outside air to inside of transformer
OIL
A Breather

19. Buchholz Relay
It gives an alarm to the operator if there is any fault in transformer
If fault continues to persist , then the relay will trip the main circuit breaker to protect the transformer
It works during:
Short-circuited core laminations
Broken-down core bolt insulation
Bad contacts
Overheating of some part of the windings
Short-circuits between phases
Earth faults puncture of bushing insulators inside tank

20. Methods of cooling of tranformer
Air natural (AN)
Air Blast(AB)
Oil Natural (ON)
Oil natural air forced (ONAF)
Oil natural water forced (ONWF)
Forced circulation of oil
Oil forced air natural (OFAN)
Oil forced air forced(OFAF)
Oil forced water forced(OFWF)
ONAF cooling provided to 220/33kV
transformer

21. RADIATOR Radiator are used in transformers to cool the transformer oil
ON & ONAF is used for cooling
It has small fins
4 – 10 radiator banks in a transformer depending upon capacity

22. The company is performing well their duties
CONCLUSION  
The company is performing well their duties
Minimizing cost of generation
State Electricity Board is a competent organization and has infrastructure to take up any challenges
I am pleased to have learnt a lot about the work culture and ethics of an organisation