A High Impedance Fault Detection Method Based on Transient Signal Difference

High impedance fault (HIF) with weak fault characteristics are present in distribution networks. The fault characteristics are easily confused with normal transient disturbances (NTD). It is difficult to be detected by traditional protection devices. In the paper, a fault detection method based on the difference of transient signal spectrograms is proposed. The transient zero sequence current signals of disturbances and faults are analyzed spectrally using the Practical MUSIC (PMUSIC) algorithm. Difference identification is calculated using F-paradigm for the matrix represented by the spectrogram. The fault similarity factor FS is used as an initiation criterion to discriminate normal disturbances from faults. The fault determination factor FD is used as a criterion for high resistance ground fault detection. It is verified through simulation that the method can correctly distinguish normal disturbances. Accurate detection of high resistance ground faults of 10kΩ is realized.