RECEIVING SUBSTATION (RSS) for DC Traction.

?RECEIVING SUBSTATION (RSS)

The HV (132KV/66KV) power supply received from Power Supply Authority is stepped down to 33 kV

TYPE OF RECEIVING SUBSTATION .

AIS ( AIR INSULATED SWITCH GEAR)

GIS ( GAS INSULATED SWITCH GEAR)

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RSS Scheme

The Electrical energy is fed from Power Supply Authority grid at the nominated receiving substations. The power is provided at 132 Kv/66 Kv level.

Each RSS has two incoming 132kV/66kV bays, two outgoing 132kV/66kV transformer bays and one bus coupling bay. Each RSS has 2 Power Transformers. The power from transformers is fed to 33kV main Incoming Circuit Breakers at RSS Building through 33kV power cables and then through 33kV cables, it is fed to ASS & TSS in Depot and Mainline Station having 33kV switchgears for distributing power further to auxiliary and traction networks.

Two feeders are installed at each RSS with 100% redundancy for the system. Each feeder is capable of feeding the entire load of RSS and coupling switchgear is provided at the incoming level to facilitate the power transfer from one cable to the other. One feeder in each RSS location serves the system, whereas another feeder is kept as hot standby.

?The substation is a single Bus system with the sectionizer dividing the Bus into two sections. Each section feeding Power Transformer which caters to both Auxiliary & Traction loads.

?RSS Layout

?The 132 kV bays contain:

?a) Two incoming sections

?b) One bus coupling section

?c) Two outgoing sections

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Incoming Section

Each incoming section consists of:

a) One lightning arrestor in each of the three phases

?b) One earthing isolator to earth in the incoming cable/OHL

?c) One voltage transformer in each of the 3-phases

?d) One triple pole line isolator

?e) One triple pole incoming circuit breaker

?f) One current transformer in each of the three phases

?g) One triple pole isolator

?h) Revenue metering equipment with the associated CTs, PTs and meters in each incomer

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?Outgoing Section

?Each outgoing section consists of:

?a) One triple pole isolator

?b) One triple pole circuit breaker

?c) One current transformer in each of the three phases

d) One lightning arrestor in each of the three phases

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Coupling and Busbar Section

?The three phase busbar section consists of:

a) One triple pole circuit breaker

b) Two triple pole isolators

c) Two nos. three phase current transformer

d) Two nos. three phase voltage transformers

?Changeover

?For 132 kV switchgear at RSSs, there is a provision for transfer of power from one feeder cable to the other feeder in case of failure of power. This transfer of power takes through an automatic device

?LTO ( LINE THROW OVER)

BTO ( BUS THROW OVER)

CTO ( CIRCUIT THROW OVER)

LTO

INSTALLED IN HV FEEDER IN C&R PANEL . IN CASER THE ENERGIZING FEEDER IS OUT OF SERVICE, ‘LTO’ AUTOMATICALLY TRANSFERS FROM INFECTED LINE TO HEALTHY STANDBY LINE WITH CERTAIN SET TIME DELAY

BTO

PROVIDED AT 33KV LEVEL. INCASE OF A TRANSFORMER FAULT OR ANY OTHER FAILURE THAT CAUSES POWER FAILURE AT 33KV INCOMING BAY THE OTHER INCOMING BAY BREAKER WILL CLOSE AUTOMATICALLY( 2 OUT-OF-3 CONFIGURATION)

CTO

PROVIDED AT 33KV LEVEL. INCASE OF FAILURE OF ONE RSS POWER IS FED FROM ANOTHER RSS.

METERING AT 123KV/66KV LEVEL

THE FOLLOWING METERING ARRANGEMENTS ARE PROVIDED ON THE INCOMING FEEDERS

1. AMMETERS???
2. VOLTMETR
3. ENERGY METER

RSS EQUIPMENT

The Receiving Sub-Station includes the following equipment:

?Switchyard

1. HV Lightning arrestor

2. HV Motorized Isolator with Earth Switch

3. HV Capacitive Voltage Transformer

4. HV Current Transformer

5. HV Potential Transformer

6. HV SF6 Circuit Breaker

7. HV/33kV Oil Type Power Transformer

8. Neutral Grounding Resistor

9. Nitrogen Injection Fire Prevention & Extinguishing System(NIFPES)

Control Room Building

1. Control & Relay Panel

2. 33kV Switchgear Panel

3. 200kVA (As required) Dry Type Auxiliary Transformer

4. UPS & UPS battery bank

5. ACDB

6. DCDB

7. Battery Charger

8. Battery bank

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