Adaptive distance protection based on waveform factor

This paper proposes a new concept called waveform factor, which can describe the distortion degree of optional data-window. Simulation results show there is a definite relationship between waveform factor and amplitude error. At present, the inverse-time characteristic of zone I distance relay has some defects such as conservative protection domain and long time delay when the fault is at the end of the protected line. To repair these defects, this paper presents an adaptive protective relaying scheme for high-speed distance protection. The scheme adjusts distance relay's setting value based on the waveform factor of fault current. When fault occurs, zone I distance relay calculates the waveform factor of fault current in real-time and adjusts its setting value according to the waveform factor, no longer adopting the inverse-time characteristic.