Experimental study on lighting shielding performance of ±500 kV HVDC transmission line

Simulation experiment is one of the important techniques for the lightning shielding performance study of EHV/UHV transmission line. A simulation experiment was carried out in this paper for studying the impact of nominal field on the lightning shielding performance of HVDC transmission line, the test equivalency was verified in following aspects: the determination of test scale, the simulation of near field during the descend leader process and the simulation of nominal field in the vicinity of model lines. The exposure space of G4-40 is received both when the polar conductor is applied with DC voltage and without DC voltage. The residue upward streamer incepted from the surface of conductors which is fail to hit and the primary discharge can be observed at the same time. According to observed phenomenon, the influence mechanism of DC voltage was analyzed qualitatively, and the shielding failure rate of positive polar with DC voltage is 1.79 times of which without DC voltage. © 2009 Chin.Soc.for Elec.Eng.