Kapil Sahani

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Presented By :

Kapil Sahani

10EGIEE029

Presented to :Mr. Shakti Singh Shekhawat

Head of the Department

Electrical Engineering



Session: 2012-13



Abstract

A practical training in Grid Sub-Station helps in getting

acquainted with the way in which our knowledge is

being practically used outside the institute and this is

normally different from what we have learnt from

books theoretically.

220 GRID SUB STATION,DEBARI is one of 220 KV

capacity gss among which those are connected in this

ring.



Introduction

Single Line Diagram Power Transformer

Instrument Transformer

Circuit Bracker

Insulators Lightning Arrester

Isolators

PLCC

Battery Section

Capacitor Bank

Conclusion



Introduction

220 KV GSS, DEBARI, UDAIPUR IS A GRID OF RAJASTHANRAJYA VIDHYUT PRASARAN NIGAM LTD (RRVPNL) .

Main supplier of electricity in Udaipur district, Banswara,

Dungarpur & part of Rajsamand.

At present Total grid capacity is 300 MVA.

After installation of new X’mer capacity will be 460 MVA.

Total normal load is about 160 to 170 MW .

peak load is 250 MW. Maximum load is of HZL, Debari,which is 36 MW



Single Line Diagram



For incoming lines GSS (220

KV)

Outgoing lines in GSS (132 KV) Outgoing lines in GSS (33

KV)

1. RAPP A 1. HZL 1. CEMENT FACTORY

2. RAPP B 2. SUKHER 2. RIICO

3. CHITTORGARH (I/C & O/G both) 3. MADRI 3. BHUWANA

4. BANSWARA (I/C & O/G both) 4. NATHDWARA 4. PRATAP NAGAR

5. KANKROLI (PGCIL) 5. MAVLI 5. BICHADI

6. BHATEWAR 6.BHATEWAR

7. UCW

INCOMING AND OUTGOING LINE



POWER TRANSFORMER

static device by means of which electric power in one circuit

is transformed into electric power of the same frequency inanother circuit



TRANSFORMER EQUIPMENTS

9

CONSERVATO

R

BUCHHOLTZ

RELAYBUSHINGS

BREATHER

TRANSFORMER

TANK



Transformer Tank

10

whole assembly of atransformer is placed in a

metal sheet tank

assembly of the transformer

is immersed in an oil whichact as an insulator as well as

coolant.

The oil will take out the heat

produced by thetransformer windings and

core



Conservator

11

A cylindrical shaped air tightmetal drum placed on a

transformer tank

It provide cooling to transformer

It provide insulation between

transformer windings.



Breather

12

apparatus with whichbreathing 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

SILICA GEL

(DRY)

OIL

A Breather



Buchholz relay

13

It gives an alarm to the operator

if there is any fault in transformer

If fault continues to persist , thenthe relay will trip the main circuitbreaker to protect thetransformer

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 bushinginsulators inside tank



Cooling of transformer

14

1. Air natural (AN)

2. Air Blast(AB)

3. Oil Natural (ON)

4. Oil natural air forced (ONAF)

5. Oil natural water forced

(ONWF) 6. 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



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

Radiator



SPECIFICATION

220/132 KV TRANSFORMER MAKE

160 MVA X’mer -1 Nos. IMP POWER LIMITED -1

100 MVA X’mer -2 Nos. CROMPTION -1

TELK

50 MVA X’mer -2 Nos. CANADIAN GENERAL ELECTRIC – 1

BHEL-1

220/132 KV TRANSFORMER MAKE

14.6/20 MVA X’mer S-I NGEF

16/20 MVA X’mer S-II NGEF

10/12.5 MVA X’mer S-III NGEF

Five step down transformers are used to step down 220kv into 132kv.

Two step down transformer are used to step down 132 kv into 33kv

Total transformer installed - 8



INSTRUMENT TRANSFORMER

Current Transformer

Potential Transformer

Transformer used in conjunction with measuring instrumentsfor measurements purposes



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 protectiverelays.



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.



Circuit Braker

An automatically operated switch

Break a circuit automaticcally

under fault condition

protect an electrical circuit from

overload and short circuit

It is an on – load device

Classified as:

•OiL circuit breaker

•Air blast voltage circuit breaker

•SF6 circuit braker

•Vacuum circuit braker



Classification of circuit braker

Oil circuit breaker: -

Uses some insulating oil for arc extinction.

Air blast circuit breaker

:-

High pressure air blast is used for extinguishing the

arc.

Sulphur hexafluoride circuit breaker:-

SF6 gas is used for arc extinction.

Vacuum circuit breaker:-

Vacuum is used for arc extinction



InsulatorsInsulators is used to hold the live conductor and to prevent leakage of the current

from the conductor to the pole.

1.Pin type Insulators 3. Strain Insulators

4. Shackle Insulators 5. Stay Insulators

2. Suspension Insulators



Lightning arrester

To protect transformer from over voltage caused

by lightning.

On the occurrence of over voltage, the air

insulation across the gap breaks down an arc is

formed, providing a low resistance path for thesurge to the ground



Isolators

used to completely de-energise the

circuit for service or maintenance

used for a isolating a circuit under no

load condition only.

have provisions for a padlock

an isolator is an off-load device .





Battery house:-

DC power supply is required for the

operation of circuit breaker and as a supply

for PLCC room and also for control room

indication.

Battery charger

It is used for charging purpose of battery

house, which is based on semiconductor

devices.

Battery section

26



The capacitor gives following functions

1. Voltage Rise

2. Energy storage

3. Power Factor Improvement

Two capacitor banks of 7.2 MVAR are used for

power factor and voltage improvement.

Capacitor bank

27



Kapil Sahani

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