The analysis of secondary arc spectrum characteristics on UHV transmission lines

On ultra-high-voltage (UHV) lines, the existence of secondary arc impact on the stable operation of system, so it is necessary to further study secondary arc. The paper adopts total harmonic distortion (THD) to judge the status of arc. First, the simulation model of secondary arc is established by ATP software. Then, faulted phase voltage and secondary arc are simulated in different close angle. Last, spectrum characteristics and harmonic content of faulted phase are analyzed, at the same time, THD is obtained by Fourier algorithm. The simulation results show that THD of faulted phase voltage decrease as close angle in every fourth cycle, which provide the basis for judging state of arc by using harmonic content of faulted phase voltage. The analysis of spectrum characteristics of harmonic content is certain significance in the design of choosing insulation materials and insulation structure.