SAS GIS EQUIPMENT OPERATION

As per SEC requirement the GIS operations ( Open /Close) should be like below.

GIS Local Cubicle Control panel contain one multi position switch
There are four position available

1.Emergency

All operation should be in LCC panel Open/close switches

2.Local

All operation should be through Bay Control relay mounted in LCC panel

Its checks all hoard wire interlock and BCU software interlock

3. Remote

All operation from HMI and SCADA

4. OFF

There is no operation from any where.
 

BREAKER FAILURE INITIATION

Transformer Mechanical Protection BF Initiation

The Breaker failure protection is used for protect the breaker when fail to open for a Protection trip.

If any protection Lock out operate it will give a trip to CB and initiate the BF relay.

After minimum time BF relay will check the CB status and fault current flow then relay will give one more trip to the CB. Now CB is still fail to open then BF relays initiate BF second stage lock out and give trip to adjacent CBs and save faulty CB.

But transformer Mechanical protection ( Main tank Bucholz relay Operate and winding temperature high and oil temperature high, PRD ) Operation independent of fault current.

Therefore BF relay should not consider fault current for transformer Mechanical protection initiation.

This initiation separate given as digital input in Numerical relays REB 500 (ABB),7VK61 ( Siemens)

But this initiation will initiate the first and second stage timers in normal non numerical relays ( RAICA - ABB).