Research On The Location Method Of Single Phase Grounding Fault For 10kV Distribution Line

10kV distribution network in China belong to medium-voltage power network, mostly use neutral non-effective grounding mode, it also called small current neutral grounding system, its corresponding single-phase grounding fault is called small current neutral grounding fault, which has the highest fault rate. In addition, 10kV distribution network has complicated geographical environment and generally adopt single power source to radiativity powersupply, the distribution line has many branches , as well as high grounding resistance at fault point and low current signal, thus result in the difficulty of locating fault. Aiming at the single-phase fault on the 10 kV distribution line, A kind of C-type of traveling wave location method is proposed in this paper.On the analysis of various traveling wave methods, choose C-type of traveling wave method to locate fault point. a new location method has been studied and finded to judge the fault segment. according to the reflection regular of traveling wave signal on the wave impendence called discontinuous point, after the single phase grounding fault happened, inject a high voltage narrow pulse signal into the fault phase and the normal one respectively, collect the reflected signals at detection point, make this two signal waveforms subtract, find the corresponding time of the fault point characteristic wave, calculate the fault distance by using location formula. Based on the fault distance, conduct wavelet packet decomposition and reconstruction on the waveform subtraction, judge the fault segment by comparing energy changed value of node characteristic waves, determine the fault point comprehensively depending on the fault distance and segment. make a deep research on some aspects including the signal resource and amplitude etc, determine and adopt the voltage traveling wave signal to judge the fault segment. Make a lot of research on the various wavelet packet function. finally choose the coif5 wavelet packet to analyse the traveing wave signal because it has better symmetry and applicability to high-frequency transient analysis. the feasibility of this new location method not only be proved through a lot of simulation experiments, but also, in lots of simulation experiments, a method was to be researched and identified to restrain clutter signal.