High-Impedance Fault Detection Method of Resonant Grounding Systems Based on the Polarity Difference of Transient Zero-Sequence Currents

To address the issue of the current distribution network's difficulty in accurately and quickly detecting single-phase high-impedance grounding fault (HIF) in lines, a method for detecting HIF in Resonant Grounding Systems based on the polarity difference of transient zero-sequence currents is proposed. By representing the nonlinear arcing high impedance through a segmented linear equivalent of the voltage-current characteristic curve during HIF, an analysis of the fault characteristics is conducted. Based on this, it is determined that the transient components of the faulty feeder and the healthy feeder have opposite polarities during a HIF. Subsequently, each feeder's zero-sequence current is subjected to low-pass filtering within the characteristic frequency band. The first extremum point is assigned a value, and an extremum point matrix is established. Finally, HIF detection is achieved through polarity characteristics.