End Fault Protection Working Principle:
End Fault Protection is used to protect the busbar from the fault nearer to the sensing device typically current transformer and circuit breaker. It is also called as blind spot bus protection. It initiates high speed trips to the remote circuit breaker.
End Fault Protection:
Consider a spot between the current transformer and the circuit breaker. Here The circuit breaker is in closed condition. A fault occurs between the spot. In this condition the current transformer initiates the trip signal to the local circuit breaker. Hence The circuit breaker got tripped on bus differential protection. But the fault still in the line. So that the relay associated with the current transformer initiates a high speed tripping signal to the remote circuit breaker. The fault become cleared. Due to the fault in the dead spot zone, The relay initiates the high speed tripping signal to the remote circuit breaker instead of the local breaker such a protection is called end fault protection.