A novel scheme for identification of lightning stroke and fault in EHV transmission lines

Identification of lighting stroke and fault is a key technology for travelling wave based protection because stroke maybe cause maloperation of protection. This paper analyzed the characters of current travelling waves induced by lightning stroke or fault in frequency domain and time domain. Energy coefficient is proposed to discriminate the lighting without fault from normal fault, and a waveform characteristic is proposed to discriminate a lightning stoke without fault and lightning stroke with fault. A novel scheme based on energy ratio and waveform characteristic is put forward to resolve the impact of travelling waves induced by lightning stroke. The simulation results from Alternative Transient Program (ATP) validate the feasibility and reliability of this scheme.