The Research Of The New Distribution Netword’ Fault Diagnosis

The so-called new distribution network means distribution networkincluded Distributed power supply (Distributed Generation-DG). Ourdistribution network is used mostly small current grounding way, so thediagnosis research refers to the research of small current grounding systemafter joining the distributed power DG, and the concrete is to complete the faultline selection and fault distance of single phase ground fault.This paper first analyzed fault transient zero sequence currentcharacteristics of small current grounding system, which included DG and doesnot contained DG. Through the contrast analysis found that, although the DGaccess changes the system’s transient zero sequence current distributionsituation, but the most critical transient zero sequence current which flowsthrough line’s CT installation area changes little. That is DG almost does notaffect the line detected transient zero sequence current. And the transient zerosequence current of fault line contains abundant fault feature information, so, aslong as they seek a kind of method to be able to collect these fault featureinformation is able to complete fault line selection and ranging work.Therefore, the paper put forward a new routing method, which use the linezero sequence current transient component’s wavelet transform. According tothe value and polarity judges the fault lines; And through the line CLP popularwave analysis, the traditional type A travelling wave ranging method isimproved. Using the wavelet transform modulus maxima detection theorydetects the moment of wave to the bus. Finally, the paper puts forward theimproved type A travelling wave method of fault location algorithm.Finally, established simulation model of phase-to-ground fault of smallcurrent grounding system with DG.A lot of simulation test verified theeffectiveness and accuracy of routing algorithm and location algorithm.