Research On Single-phase-to-ground Fault Location In Multi-branch Distribution Network

The research on fault location of distribution network mainly includes the research on section location and the research on accurate fault location.The former mainly locates the area where the fault occurs,which can help the grid side to quickly isolate the area where the fault occurs and reduce the power supply impact on the non-faulty area.The latter is mainly aimed at the located fault section,quickly and accurately find out the location of the fault,repair and restore the power supply of the affected area,and improve the stability of the Distribution network.This paper conducts an in-depth analysis of the zero-sequence network after a single-phase grounding fault occurs in the neutral point of my country's power distribution network,and combines it with Matlab/Simulink simulation to verify it.Aiming at the problem of locating faulty sections in the distribution network under multiple branches,a section locating method combining power polarity and zero sequence current similarity is proposed.Then,the principle of the accurate fault location method based on traveling wave is analyzed.According to the principle of the double-terminal traveling wave location scheme,a three-terminal traveling wave location method applicable to the T-shaped branch line section is proposed.The modal aliasing phenomenon existing in the EMD decomposition of the HHT time-frequency analysis method used in the ranging is improved by the introduction of the MCEEMD decomposition algorithm.The IEEE33-node distribution network simulation system is built by Matlab/Simulink,combined with the Three-Phase Fault module to set different fault conditions,and a large number of simulation tests are performed to verify the fault location method proposed in this article.Experiments show that the proposed method can effectively solve the fault section location under multi-branch,and the accuracy of accurate fault location is also improved to a certain extent.