A Presentation

On Summer Training

At Power Grid Corporation Of India Limited,

Bahadurgarh

What is POWERGRID???

• The Power Grid Corporation of India Limited (POWERGRID), is an Indian state-owned electric utilities company headquartered in Gurgaon, India.

• POWERGRID transmits about 50% of the total power generated in India on its transmission network.

• India’s largest Electric Power Transmission Utility.

400/220 KV Substation ,Bahadurgarh

1. 400 KV Lines

2. 220 KV Lines

Key to abbreviation

BH - Bhiwani BW - Bawana S1 - Sonepat Line 1 S2 - Sonepat Line 2 N1 - Nunamajra Line 1 N2 - Nunamajra Line 2

Different parts of Bahadurgarh substation

•Switchyard•Control room•Battery room•Firefighting pump house •D.G. set room•AHU room•ACDB/DCDB room

Switchyard

1.Interconnecting transformer 5.Isolator2.Lightning arrestor 6.Circuit breaker3.Capacitive voltage transformer 7.Current transformer4.Wave trap 8.Earth switch

1.Interconnecting transformer

The ICT is a step down transformer. It has three windings. Primary or High voltage (HV)-400 KV, secondary or intermediate voltage (IV)-220 KV, tertiary or low voltage (LV)-33KV.

2.Lightning arrestor

• It avoids the over voltages from entering the switchyard.• Protection of the buses and equipment during Lightning surges.

TYPES :Silicon Carbide (SiC) – Gap typeZinc Oxide (ZnO) - Gapless

3.Capacitive voltage transformer• The CVT is used for

metering purpose for monitoring the line voltages. • The CVT is used for

protecting the line against over voltages by connecting to relays which form the protection circuits.

4.Wave trap

• A wave trap is a device that allows only a particular frequency to pass through it that is it filters the signals coming onto it.• It is installed in the phase

which is used for PLCC.

5.Isolator• An isolator is basically a switch that can be operated mechanically or electrically as well. • The isolator cannot be used to shut down a line in loaded conditions as in an isolator arc

is not quenched. This arc can damage the isolator or other equipment.

Double Break Centre Break

6.Circuit breaker• To breaks a circuit either manually or

automatically under all conditions at no load, full load or short circuit.• It can be used to discharge the line in

loaded conditions also. • The CB may be of different types:a) Air Blast Circuit Breakers

b) SF6 Circuit Breakers

c) Vacuum Circuit Breakersd) Oil Circuit Breakers

7.Current transformer• Current transformer (CT) is an equipment

that steps down or steps up the value of current as required.

Functions of CT :• Electrically isolates the instruments and

relays from High Voltage side.• Measures / monitors current.• Used in Measuring power flow.• Senses abnormalities in current for system

protection.

Current transformer

8.Earth switchAn Earth switch is used to provide ground to the Electrical circuit

required for maintenance. It is mounted with the Isolator.

Control room

Different equipment in the control room are listed below:•Metering and control panels•Protection/relay panels•PLCC

Battery room

• In the battery room, batteries are installed which provide DC supply for the substation operation. DC supply is required for the operation of relays in the control panel and for the operation of PLCC.

AHU room

• The control room is very large. The control room needs to be air conditioned so that the relays can operate normally. For cooling the control room an air conditioning plant has been installed in the substation on the roof of substation.

Firefighting pump house

• The firefighting pump house is connected with two water tanks. In the pump house four different pumps are present there which work in different conditions of water pressure. • There are two jockey pumps, one Diesel engine set pump and one

HVW pump. • There is an air vessel that maintains the pressure in the pipes when the

water flow is low.

Firefighting pump house