Fast and Secure Numerical Breaker Failure Protection

This paper presented two algorithms for enhanced numerical BF protection. The fast reset algorithm for current-based BF detector is based on differentiating between the rotating pattern of a fault current and the decaying pattern of a subsidence current. The algorithm is simple, yet very fast and robust. It uses few factory constants, but they have well defined meanings and can be easily fine tuned in any particular implementation that follows our approach. The algorithm can be further enhanced by recognizing that when the current vector stops rotating and starts decaying due to subsidence, it actually rotates at a significantly lower rate, but in the opposite direction compared with an alternating current. This reversal of the angular speed can be used to strengthen and speed up the algorithm