A High-Impedance Fault Feeder Detection Method for Resonant Grounded Active Distribution Systems Based on Polarity and Harmonic Wavebody Similarity

High-impedance fault (HIF) feeder detection in resonant-grounded active distribution systems remains a challenging issue. In practice, fault currents are typically weak, and the integration of distributed generation (DG) often distorts fault signatures, significantly limiting the effectiveness of existing detection techniques. This paper presents a novel HIF feeder detection method based on the fusion of zero-sequence current (ZSC) cross-correlation polarity analysis and harmonic wavebody similarity matching. Firstly, the HIF mechanism is examined, and the impact of DG on ZSC behavior is characterized, revealing polarity differences among feeders. To suppress high-frequency interference, variational mode decomposition (VMD) is employed to extract low-frequency components indicative of ZSC polarity, which are then subjected to cross-correlation analysis and used as the primary detection indicator. When ZSCs are heavily distorted due to DG, harmonic wavebody similarity serves as a supplementary detection feature. A comprehensive detection criterion is subsequently formulated by combining both analyses. Simulation and experimental results demonstrate that under HIF conditions, the proposed method is robust against variations in fault location, fault type, and noise interference, and can accurately identify the faulty feeder. Moreover, it remains effective for arc grounding, grass grounding, and pond grounding scenarios, highlighting its strong practical applicability.