Effect of environment factors on ac flashover performance of 3 units of polluted insulator strings under natural fog condition

The electrical characteristics of contaminated insulators wetted by natural fog are rarely reported at home and abroad. Based on natural fog observations for 4 years at Xuefeng Mountain testing station, the AC flashover performance of three units of polluted insulator strings wetted by natural fog was studied. The results show that there are some differences on the flashover voltage stress between results of field test and Baker et al. The AC flashover process of the polluted insulators mainly includes wetness of the contamination, formation of dry bands, burning and elongation of partial arc and flashover. Moreover, the wind velocity has influence the flashover performance of insulator strings.