Fault Location Method Of Single-phase To Earth Fault In Distribution Network Based On The Variance Of Three-phase Asymmetrical Current Fault Component

When single-phase earth fault occurs in the distribution network, the three-phase fault path current is different from the non-fault path current that can be used for line selection. However, the fault component signal of the three-phase current is not obvious, because the three-phase load current is far greater than the fault component current that will lead to the failure of the method for detection of earth fault. Improved fault location method based on the three-phase line current is proposed in this paper. The faulty component of the three-phase current is obtained by subtracting the value of phase current before failure from the value of current that appears after failure, and then the zero sequence line current is subtracted from the faulty component of each line to enhance the difference of line currents. The variance of the fundamental wave amplitude of the three-phase difference result is calculated, so that the fault characteristics of the faulted path are significantly different from the healthy path. Finally, the fault location is detected by comparing the results of different lines. In this paper, the specific fault location process and criteria are given, and the reliability of the method is verified by simulation experiment and actual data.