Due to the complex structure of urban distribution networks, which are mostly cable and overhead mixed lines, and the neutral point is often grounded through arc suppression coils, when the system is single-phase grounded, the grounding current at the fault point is often weak, making it difficult to directly select the fault line by steady-state electrical quantities. This article creatively proposes a fault line selection method that combines transient zero sequence current and wavelet decomposition. The method quantifies the fault characteristic values and provides a fault diagnosis logic. Multiple sets of simulation data show that the fault line selection method proposed in this paper is not affected by factors such as distribution network structure, fault point location, closing angle during grounding fault, and resistance of fault point, and has good prospedts for engineering application.

fault line selection  /  wavelet analysis  /  fault eigenvalue  /  correlation analysis  /  resonant grounding system