Study On Method Of Lightning Strike Identification And Fault Location Of Transmission Lines Based On Current Traveling Waves

Transmission lines are an important part of power system, line fault is mostly caused by lightning strike. Lightning strike interference identification is an important basis for the accuracy of fault analysis, characteristic value of lightning identification method is improper selection, easy to cause miscarriage. Traveling wave method has obvious advantages in fault location of transmission lines, however, there are some problems still not be well resolved, the accuracy of actual location is not higher. In this paper, lightning fault identification method, the traveling wave detection method and the traveling wave locating algorithm of transmission lines are studied, and fault location method of double-circuit transmission lines on a same tower based on the traveling wave is studied too.A new identification method of lightning strike interference and fault types is proposed in this paper. The simulation model a 220kV transmission system is constructed, the feature differences of transient current waveform are analyzed when lightning and short-circuit occurs on transmission lines, the waveform characteristic value in the time domain and the energy ratio of high frequency and low frequency of transient electric wave are extracted respectively to structure identification criterion, realizes the identification of lightning strike interference and fault types step by step, which improved the accurate rate of identification.A method of traveling wave detection based on variational mode decomposition (VMD) and teager energy operator (TEO) is proposed in this paper. A new phase transformation matrix is introducing, a single current mode component is used to reflect the feature wave of fault types, which can simplify the select process of fault traveling waves. And then the current mode component is taked to decompose by VMD, the instantaneous teager energy of high frequency modal component is calculated, the moment of the first peak on the instantaneous energy curve corresponding is the time of fault initial waves gets to measurement point. The traveling wave detection results of the proposed detection method are compared with the results of wavelet transform and Hilbert Huang transform method by simulation.An optimization algorithm of fault location based on double-terminal traveling waves is proposed in this paper, the algorithm is not affected by wave velocity. Draw lessons from the current fault locating algorithm that is not affected by wave velocity, start from the actual route of fault traveling wave on transmission lines, two optimization algorithm of fault location based on two double-end traveling wave are deduced, and then the optimal algorithm scheme is determined. The algorithm uses the moment of fault initial waves gets to measurement point and the given line length to calculate fault point in the horizontal distance of the line, which improves the efficiency of troubleshooting. The method was applied to lightning fault location of transmission line, the problem that lightning strike point and fault point is inconsistent is solved.A traveling wave fault locating method of double-circuit transmission lines on a same tower based on VMD and TEO is proposed in this paper. The influence of distributed capacitance and operation mode on transmission line fault location is analyzed, the selection problem of fault feature wave under multimode component is solved by using a phase transformation matrix suitable for double-circuit transmission lines on a same tower, then take the fault locating method based on VMD and TEO to realize traveling wave fault location of double-circuit transmission lines on a same tower.A large number of simulation results verify the correctness of the proposed method in this paper, and accuracy of fault location is higher.