Detection Method of High Impedance Fault in Distribution Network Based on Multi-resolution Wavelet Transform

When a high impedance fault occurs in distribution network, the sudden change of electrical quantity of fault characteristics is weak. The existing fault detection methods are difficult to effectively identify the characteristics of high impedance fault, and are easy to be disturbed by interferences such as harmonic and noise. In order to realize the reliable detection of high impedance fault, a high impedance fault detection method based on multi-resolution wavelet transform is proposed. Combined with the frequency domain distribution characteristics of zero-sequence voltage under faults, the zero-sequence voltage is processed by multi-resolution wavelet decomposition, and then the detail coefficients are reconstructed under different frequency bands. Finally, the sum of the absolute values of the reconstructed signals within the power frequency cycle are calculated before and after the faults. And the changes before and after the fault with the preset threshold are compared to realize the effective detection of high impedance fault. A large number of simulations show that this method can be adopted to accurately distinguish faults and interferences, and has strong adaptability to high impedance fault detection in different distribution network scenarios. © 2023 Science Press. All rights reserved.