Breaker Failure Initiate

[pukar12345]

Hi everyone,

Can anyone explain me how BREAKER FAILUR INITIATE works ?

I have a scheme having Bus bar with 3 outgoing feeder and 1 incoming feeder.

If outgoing 1 fails to trip, then Breaker failure relay at outgoing feeder 1 sends trip signal to trip outgoing feeder 2, outgoing feeder 3 and incoming feeder 1.

Then do Breaker failure relay need to send another breaker failure initiate signal to incoming feeder as well outgoing feeder 1 and outgoing feeder 2 ? and what is the purpose of that ?

 

[odlanor]

If you assume a BF protection for a CB, there are 4 components:
1- initiation relays
refers to protection relays that trips CB. They must start BF scheme.
2-temporizer relay (62BF)
this relay is energized by initiation relays and operate 86BF after a time that is supposed CB did not work.
3-reset relay (50BF)
If current of CB circuit vanish . means CB has opened, so this relay that block trip of 62BF.
4 block relay(86BF)
After energized by 62BF , trip and block all adjacent CBs of CB with failure.

 

[davidbeach]

Any decent modern relay can do its own breaker failure. If the breaker doesn't trip and interrupt the current, trip the bus lockout. Tripping of the bus lockout should initiate breaker failure of the incoming so that if the incoming breaker also fails to interrupt the current, something upstream can be tripped.

 

[ndondo]

from my understanding of breaker fail and how it works it is there to protect the feeder in the event of a fault that occurs to that specific feeder and a protection relay does trip but the breaker fails to trip and the relay sends the signal to the incomer then the incomer should trip to isolate
the supply that goes to the feeders.