Research On Fault Location Of Complex Distribution Network Based On Wide-area Transient Traveling Waves

The complex circuit structure and numerous equipments in the distribution network lead to a large increase in the number of grounding faults.At the same time,the special grounding mode of the neutral point of the distribution network makes the current flowing through the fault point of the circuit very small after the single-phase grounding fault occurs,resulting in the difficulty in determining the fault location.Therefore,this paper focuses on how to accurately identify and locate low-current grounding fault in distribution network,and carries out research from theoretical analysis,algorithm design,simulation verification and other aspects.The main research contents are as follows:Firstly,the wave process and wave reflection principle of transmission lines are analyzed,and the transmission characteristics of downstream wave in distribution network in line-cable hybrid lines and multi-outlet nodes are studied.The applicability of various fault location methods based on traveling wave information in complex distribution networks is compared.Secondly,the propagation path and characteristics of the effective traveling wave head in the transient traveling wave signal are analyzed,and the wave head polarity and wave arrival time distribution characteristics of the transient traveling wave information are studied.Combined with the principle of binary recursive SVD decomposition,a fault location method for distribution network based on common characteristics of wide-area traveling wave information is proposed by taking transient traveling wave signals of measuring points at each outgoing line terminal of distribution network as inputs.The method realizes accurate location of short-circuit faults in distribution network of pure overhead lines with outgoing lines containing T connections.Finally,the influence of fault location,transition resistance and voltage phase angle on the waveform of simulated traveling wave is analyzed through simulation research.Based on the principle of post-test simulation and Pearson correlation theory,a fault location method for distribution network based on wide-area traveling wave post-test simulation is proposed by taking transient traveling wave signals of measuring points at each outgoing terminal of distribution network and a sample library of simulated short-circuit fault waveforms of distribution network as input variables.The method realizes accurate location of short-circuit faults of distribution network with Tconnection outgoing line and distribution network with power cable outgoing line.