A Novel Fault Section Location Method Based on Energy Spectrum Entropy of EMD and Fuzzy C-Means Algorithm for Small Current to Ground System

A fault location method of small current to ground system is proposed in this essay. First, the IMF component is obtained through the EMD of the transient zero-mode current at each detection device or FTU when fault occurs. Second, the definition of EMD energy spectrum entropy is put forward to measure the distribution of signal energy in the scale domain, based on which the energy spectrum entropy factor value reflecting the highest frequency IMF component is obtained. Third, FCM algorithm is adopted to cluster analyze the first IMF component spectrum entropy factor from the two feature matrixes of local and global variables. Finally, the fault section is accurately judged through the evaluation of the fuzzy membership degree matrix. In addition, the analysis of global variable clustering center matrix can show the slight differences between the IMF1 power spectrum entropy factor value of health section and that of fault section. A good many simulation calculations show that, this method can accurately and reliably judge fault sections at any time under any grounding resistance value whether it is in the neutral point ungrounded system or arc suppression coil grounded system.