Breaker failure relays detect these conditions and initiate backup procedures.

Breaker failure relays are applied on a per breaker basis. That is, one breaker

failure relay for each breaker in the substation. BE1-BPR relay outputs must be

arranged to initiate the tripping of all the circuit breakers necessary to isolate

the fault if the protected circuit breaker fails to operate. The relay may also

need to initiate transfer tripping of remote breakers to accomplish this task.

Transfer tripping of the remote line end for a breaker failure should also block

reclosing of the remote circuit breakers. External lockout  relays are typically

used to trip and block reclosing of the backup breakers because they normally

require a positive operator action to reset them.

Typically, breaker failure protection is applied to transmission and sub-transmission

systems. However, breaker failure protection may be applied to any portion of the

power system where failure of a circuit breaker to operate properly could result in

severe system damage or instability. Breaker failure protection can also be used to

selectively clear a failed breaker in a station with multiple buses without clearing

the entire station.