Single Phase Grounding Fault Line Selection Method of Coal Mine Power Grid Based on Smooth Decomposition Modified Threshold Denoising and Waveform Diversity

Abstract

Aiming at the problem that it is difficult to select the fault line correctly when a single-phase grounding fault occurs in the coal mine power grid, this paper proposes a new line selection method based on smooth decomposition modified threshold denoising and waveform diversity. Firstly, Smooth decomposition modified threshold denoising method is used to denoise the transient zero-sequence current waveform of each line, then the comprehensive diversity matrix of lines is calculated according to cosine similarity. Finally, the comprehensive diversity matrix is analyzed by boxplot method to realize the correct line selection. The algorithm proposed in this paper is simple to implement and easy to apply in engineering with high accuracy and strong applicability. The simulation analysis shows that the proposed algorithm can still achieve correct line selection under strong noise scenarios. And the accuracy of line selection results is not affected by factors such as fault line, fault location, fault closing angle and grounding resistance.