Faulty-line Selection Method Based on Pearson Correlation Coefficient in Neutral Non-effectively Grounded SystemsOA

When a single-phase grounded fault occurs in a distribution network,a quick selection of the faulty line is crucial for the safe and reliable operation of the network.To address the low accuracy of selection devices in detecting grounded faulty lines,a line selection method based on the Pearson correlation coefficient is proposed by analyzing the similarity of the zero-sequence current fitting curve and the slope curve of each line in the distribution network when a single-phase grounded fault occurs.The apparent difference between the slope of the zero-sequence current fitting curve of the faulty and healthy lines is used to select the faulty line.Specifically,a local weighted linear fitting and differentiation are performed on the zero-sequence currents of each line to obtain the corresponding slope curves.Subsequently,the similarity of the slope curves of the zero-sequence current waveforms of the adjacent lines is used to determine the faulty line.If the similarity between a line and two adjacent lines is poor or negative(Pearson correlation coefficient close to or less than 0),it is determined as a faulty line.If the similarity between a line and at least one adjacent line is high(Pearson correlation coefficient close to 1),it is determined to be a healthy line.If the similarity of the slope curves of the zero-sequence current waveform of all lines is high(Pearson correlation coefficient close to 1),it is determined to be a bus fault.Matlab/Simulink simulation results showed that the proposed method is effective under various fault conditions and has a high detection sensitivity to high transition resistance faults.