Distributed fault monitoring devices have been widely applied to the field of fault location for power trans-mission lines.Nevertheless,the quality of these products varies,and certain manufacturers rely solely on changes in traveling wave currents or power-frequency currents for fault location,resulting in significant accuracy issues.In response to this challenge,this paper introduces a testing method that comprehensively considers changes in both traveling wave currents and power-frequency currents.Firstly,a time-sequenced logical design of traveling wave currents and pow-er-frequency currents is executed,and an accuracy testing method is proposed.Subsequently,based on simulation and experimental methods,the selection and design of current sensors are conducted.Finally,a testing system for distributed fault monitoring devices is developed,and research on factors affecting test accuracy is completed.The results demon-strate that,during the testing process,the transition duration of lightning-induced faults is shorter than one cycle,enabling the faithful replication of the timing of lightning-induced fault waveforms.Current sensors A621 and TRCP3000 can be effectively combined for testing,satisfying the requirements of measuring traveling wave currents ranging from 10 A to 1000 A.The time difference between the two lightning current wavefronts varies from 1 to 100 μs,enabling the random configuration of fault point locations.Moreover,the testing accuracy of db1 surpasses that of db4,and robustness of the db4 is superior to that of db1.When the signal-to-noise ratio exceeds 20 dB,the testing standards can be met.These re-search findings offer technical supports for improving the accuracy of fault location in distributed fault monitoring devices for lightning strike fault.
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