What are the failure modes of a breaker?

There are two main failure modes of a breaker; failure to trip, and failure to clear. Some BFP schemes cover additional failure modes such as loss of dielectric material/pressure, loss of energy in its mechanics, and contact flashover. III. BFP SCHEMES Scheme Varieties Clause 6 of the guide discusses a variety of BFP schemes.

What is a breaker failure?

Breaker failure can be defined as a misoperation or failure of a circuit breaker to operate as intended. This can result in failure to trip, close, and/or clear.

What happens if a breaker fails?

If the operator does not have a breaker failure target or alarm, then the time needed to identify the faulted breaker may be unreasonably long, resulting in a lengthy outage until equipment is placed back in service. In the worst case, the operator may test the faulted breaker, resulting in a dangerous and catastrophic failure.

What is a minimum breaker failure time delay?

Minimum breaker failure time delays are applied for all fault types to enhance system stability, limit equipment damage, improve coordination of overlapping protection schemes, and improve quality of supply by minimizing the duration of power system voltage dips. The guide further documents the criteria for setting the breaker failure time delay.

What is breaker failure protection logic?

Breaker failure protection logic is a backup protection scheme intended to guard against situations where the protection system calls for a breaker trip to isolate a fault and the breaker fails to trip and clear the fault as expected. This requires tripping further out from the fault while minimizing the additional impact to the power system.

What happens if a breaker fails during a non-fault condition?

Upon detection of a breaker failure during a fault condition, the scheme is designed to take appropriate action to clear the fault. Upon detection of a breaker failure during a non-fault condition, the scheme may take other appropriate action.