Analysis and verification of a novel current comparison pilot protection

In actual electric power system, the relay protection device plays an important role to maintain its stable operation. This paper proposes a novel current comparison pilot protection principle based on the change of current phase angle. When internal fault occurs, the change direction of current phase angle at two ends of transmission line is opposite. However, when external fault occurs, the change direction of current phase angle at two ends of transmission line is the same. Based on that, the proposed principle can determine internal or external fault correctly. Compared with traditional pilot protection principles, the proposed protection principle has several advantages. In addition, the correctness of the novel pilot protection scheme are verified by using field fault data recorded from 500kV transmission line.