Single Phase To Ground Fault Line Selection And Section Location Based On Transient Characteristics

The resonance grounding method is helpful to improve the reliability of power supply,but the difficulty of detection is greatly increased because of the weak fault current,so there are still shortcomings in the existing line selection and section location method.Based on the study of transient zero mode current characteristics,this paper explores a new method for location selection and location.First,an equivalent model of single-phase grounding fault with branch resonant grounding power network is established.Based on the null model network research and simulation feature analysis table:the transient zero mode current waveform of the fault branch and the non fault branch has obvious difference.The transient zero mode current waveform of the non fault branch is similar,the fault feature provides the theoretical support for the line selection,and the amplitude and polarity of the zero mode current in the upper and lower reaches of the fault point.There is a significant difference.The transient zero mode current at the same side of the fault point is similar.The fault feature provides theoretical support for the location of the fault.A line selection method based on transient zero mode differential current and signal inter distance algorithm is proposed.First,the transient zero mode differential current algorithm is used to distinguish between the bus fault or the branch fault.Secondly,if the branch fault is used,the similarity degree of the fault branch and the non fault branch transient zero mode current is analyzed based on the signal mutual distance algorithm,the distance coefficient matrix is constructed,the line selection vector is determined,and the selection line vector is selected.The fault line is determined by the minimum element.Finally,the correctness of the line selection method based on the transient zero mode differential current and the signal mutual distance algorithm is verified by a large number of simulation and experiments.After identifying the fault line correctly,we can further reduce the search area and locate the fault location.A location method based on signal cross range is proposed.First,the fault path is determined by the size of the transient zero mode current mutual distance at the branch node of the line.Secondly,based on the identified fault path,the location vector is constructed according to the mutual distance of the signal,the largest element in the vector is selected and the fault section is determined.Finally,a large number of simulation and experiments verify the basis of the letter.The effectiveness of the location algorithm is also discussed.