摘要

To analyse the lightning impulse breakdown characteristics of the parallel gaps of contaminated insulators with different salt densities, the SC-210 porcelain cross-arm insulator was used to conduct the lightning impulse test. Comparing with the electric field simulation results of the clean and contaminated insulators, the phenomenon of flashover along the surface of the insulator was analysed several times during the test. The tests and analysis indicate that in case of the SC-210 porcelain cross-arm installed with parallel gaps, its lightning impulse breakdown voltage U50% decreases with increasing salt density and tends to saturate more readily. The voltage-time characteristics curve of the lightning impulse of the contaminated insulator and the lightning protection gap gradually intersect, and the phenomenon of flashover along the surface of the insulator occurs several times during the test. The results of the study suggest that the effect of contamination on the flashover/breakdown location on the surface of the insulator should be considered in the insulation timing of the parallel gap and the insulator string.

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