Natural Frequencies Based Fault Location Method for Transmission Network Considering Measurement Device Invalidation

In allusion to fault location failure caused by the invalidation of measurement device in power grid,considering the invalidation of measurement device a fault location method based on natural frequencies of transmission lines is proposed.According to the law,by which post-fault traveling wave propagates in transmission network,firstly,different features of propagation paths of traveling wave corresponding to natural frequencies of faulty line and healthy line are analyzed and on this basis according to the result of comparing the sum of the length of propagation paths of traveling wave measured at the two terminals of faulty line with the full length of the faulty line,the faulty line can be determined;then the fault distance can be calculated by natural frequency-based fault location method.In the proposed method,considering invalidation of measurement device the faulty line is distinguished by frequency information of adjacent transmission lines,and then the fault distance is determined.A lot of results of simulation based on PSCAD/EMTDC and Matlab show that the proposed method is independent to transition resistance,fault distance and initial phase angle when the fault occurred,so it possesses good adaptability.