지락 과전류 계전기 동작 시간차를 고려한 직류철도 선택지락 보호 알고리즘 = A Selective Ground Fault Protection Algorithm Considering the Operating Time Difference of a Potential Relay For DC Railway Systems

다국어 초록 (Multilingual Abstract)

The ground faults in the DC railway systems are ususally detected by a potential relay(64P). But It can not detect a fault if a fault occur with a fault resistance over a certain value. Moreover, if the rail potential goes high in the ordinary operating state because of the traction load, the potential relay would be maloperated. A modified protective relaying algorithm that can identify exactly the faulted region and can distinguish a ground fault from the potential rising of the rail is presented in this paper The proposed algorithm is independent of the operating time difference of the potential relays.