High-Impedance Grounding Fault Detection and Location for Resonant Grounding System Based on Lissajous Curve Analysis

The detection and location of high-impedance grounding faults (HIGF) are challenging in resonant grounding system, as the fault current is very weak and can be easily masked by other disturbance events. After analyzing the multi-dimensional fault features extracted from synchronous measurement data, this paper proposes a method for HIGF detection and faulty section location based on Lissajous curve theory. Firstly, the area of Lissajous curve is extracted to detect HIGF, and an adaptive triggering criterion is designed by analyzing its probability distribution. Secondly, mathematical morphology is applied to extract the distortion complexity index, which is then used for distinguishing HIGF from switching events. Finally, considering the impacts of detuning rate, damping ratio and the feeder length, the ratio between zero-sequence differential voltage and zero-sequence current is analyzed within a selected frequency band, and a faulty section location method based on the slope of the differential Lissajous curve is proposed. Extensive simulation experiments and field case studies demonstrate the effectiveness and reliability of the proposed method.