High impedance fault detection for resonant grounding distribution systems based on transient component full-period differentiated measurement

Abstract

High impedance fault (HIF) signals in resonant grounding systems are weak and easily confused with conventional disturbances, which makes detection challenging. Existing single-criterion detection methods often lack reliability, while multi-criterion approaches offer limited improvement due to insufficient complementarity among the criteria. To address this issue, a detection method based on full-period segmented analysis of transient components is proposed. First, the differences in polarity, energy, and similarity of transient components between faulty and healthy feeders under single-phase HIFs are analyzed. Next, the transient voltage and current components within three cycles after the fault are extracted and divided into three segments. In Segment ①, Criterion 1 is established based on the opposite polarity of the transient current projection coefficients onto the transient voltage between the faulty and healthy feeders. In Segment ②, Criterion 2 is derived from the maximum deviation in normalized transient average energy. In Segment ③, Criterion 3 utilizes the minimum similarity between the normalized transient component of the faulty feeder and those of the healthy feeders. Meanwhile, to balance speed and reliability, correction weights for the criteria are assigned based on energy ratios across different segments, and corresponding logic thresholds are applied to achieve accurate HIF detection. Simulation and field test results verify that the proposed method is resistant to disturbances, unaffected by transition resistance, fault location, and initial phase, and remains effective under arcing conditions and noise interference.