Analysis on flashover performance of polluted porcelain insulators in high conductivity fog environment

Except from the two basic and conventional contamination accumulation modes, the common slow solid mode and the rapid liquid mode, there is another kind of rapid contamination accumulation mode which is even easier to cause the pollution-flashover. It is related to human activities, such as burning straw and setting off firecrackers, or natural factors as forest fire and acid rain. Those factors result in the weather condition of high conductivity and high humidity, due to whom the rapid contamination accumulation is added to the normal one. In this paper, the relationship between flashover voltage and the fog conductivity is researched, by doing artificial polluted tests using porcelain insulators of XP-70. Contrast to the process of the pollution's getting wet under the clean fog, the variation characteristics of flashover voltage under the high conductivity fog is systemically studied. It is pointed out that the high conductivity fog decreases flashover voltage, which is more notable on low salt deposit. After studying the changing law of the flashover voltage under different fog conductivity and salt deposit, the relational expression among them was obtained. According to the local meteorological environment, the warning model was revised, by using the expression. It also can be decided if the insulation configuration should be improved.