Grounding fault test technology of distribution network based on zero sequence power direction judgment

Abstract

Distribution network grounding fault testing technology relies on a single criterion, which has a positioning blind area, resulting in large ranging error. In this paper, a grounding fault test technology for distribution network based on zero sequence power direction determination is proposed. The direction from the power supply side to the load terminal is specified as the positive direction of the network, the fault equivalent zero sequence current is modeled, and the high-frequency component of transient zero sequence current containing main fault characteristics is extracted. The fault line is determined based on the zero sequence power direction. For the fault line, the zero sequence power is less than zero, and the absolute value is much greater than the normal line, and the line selection device can select the line normally. The grounding fault test model of distribution network is established, and the fault current difference of each measuring point is calculated. When the difference is the smallest, it is identified as the fault location. The average ranging error of the test technology based on zero sequence power direction determination is 50.68m, which is 20.24m and 23.55m lower than that based on wavelet analysis and EMD. Therefore, it can accurately determine the fault line and has strong positioning advantages.