Distribution Line Fault Location With Unknown Fault Impedance Based on Electromagnetic Time Reversal

Rapid and accurate location of power distribution line faults is essential for power system reliability improvement. Based on the electromagnetic time reversal (EMTR), an improved expression of fault current considering the influence of both sides of the transverse branch in the reversed time was derived in this research. In the reversed time, the transient voltage signals were injected into both ends of the line and multiplied one signal by −1, as suggested in An et al.'s work, and an assumed impedance of the transverse branch was set to 1000 Ω. A new criterion of the mirrored minimum fault current signal energy was proposed to determine the fault location. In the direct time, by setting different ground fault impedances, the distribution of the fault current signal energy in the frequency domain was calculated. Furthermore, the time-domain simulation verification was performed in the power systems computer-aided design software. The results indicate that when the actual fault impedance was unknown, the accurate fault location of the distribution line can be achieved by the proposed EMTR-based method, and it is less affected by time synchronization.