An Improvement of Digital Distance Relay Reliability using Neural Networks

신경회로망을 이용한 디지털 거리계전기의 신뢰도 향상

Because of the zero sequence mutual coupling of parallel lines, the distance calculation performed by a distance relay is incorrect. To achieve correct operation, the relay has to use not only the measured quantities of faulty line, but also the zero sequence current of healthy line. But the zero sequence current of the healthy line cannot be always measured. Therefore, we propose the neural network method to estimate the zero sequence current and the criterion to determine whether faulty line or not.