Analysis Of Lightning And Polluted Flashover On Transmission Line And Protective Measures

In our power supply system, the pollution flashover of contaminated insulator under power frequency on the transmission lines which are in serves is one of vital causation that lead to the tripping of transmission lines. During the lightning strike time,it is another important factor that cause it to trip. Today, we have done a lot of investigation about the pollution flashover of the line contaminated insulator only under the AC voltage. And the flashover characteristics of clean insulator only under lightning impulse have been researched by lots. But in practices, the pollution insulator is enduring the AC voltage when it is exposed to lightning strikes, and that the cases like this appear far and near. Based on the old analysis of flashover mechanisms, people generally believe that the power frequency voltage, not the lightning impulse, lead the insulator to flashover. They think that the electricity strength of the line contaminated insulator under lightning strike.Just aimed at above-mentioned questions, this paper concludes and analyzes the mechanism of generation of the lightning impulse and the mechanism of pollution flashover, then, according to solid-layer method, by simulating the case that the insulator under AC voltage which is in different pollution classes (including clean condition ) meet with the same polarity lightning impulse voltage, we have done a lot of tests and get a lot of data which are useful. Going ahead from this, we analyze the flashover mechanism, relevant parameter of electricity strength and pollution flashover characteristics of the contaminated insulator, which is undergoing the power frequency voltage when met with the lightning impulse voltage.At last, based on what the paper represented above, we analyze and concludevatiours sorts of counter measures that can be adopted popularly nowadays.