Influence of Cloud-to-Ground Lightning with long Continuing Current on the Operation Characteristic of 500 kV DC Transmission Line

Abstract

The operating experience of power transmission lines shows that the influence of the continuous current process after cloud-to-ground (C-G) lightning return-stroke on the DC line cannot be ignored. Therefore, the characteristics of the continuous current are analyzed statistically in this paper. The lightning overvoltage simulation model considering the long continuous current is built, and the influence of the long continuing current on the operation characteristic of 500 kV DC transmission line is analyzed by simulation. Simulation results indicate that the long continuous current has less effect on the overvoltage amplitude of the transmission line. But after the lightning causes the insulator flashover, the flashover current of the insulator is increased by about 47% of the continuous current amplitude. When the arrester is in normal operation, the energy absorption is mainly determined by the stage of the return-stroke, and the existence of continuous current has almost no influence. However, when multiple return-strokes cause the arrester to fail, the influence of the continuous current needs to be considered.