AC/DC FLASHOVER PERFORMANCE AND ITS VOLTAGE CORRECTION OF UHV INSULATORS IN HIGH ALTITUDE AND ICING AND POLLUTION ENVIRONMENTS

Based on the test results carried out on 160kN porcelain and glass AC insulators, a DC insulator and a 35kV composite insulator in the artificial climate chamber, this paper puts forward the flashover performance of the tested insulators in coexisting condition of high altitude, contamination and icing, and analyzes the effect of various pressures and contaminations on the AC and DC flashover voltages of the insulators without ice, and the effect of ice amount on them under high altitude and contamination condition respectively; it obtains the correction formula of flashover voltage and its special exponent for the tested insulators in the coexisting condition of high altitude, contamination and icing. According to test results, it indicates that the flashover voltage of the tested insulators decrease in exponential low with the increase of altitude, contamination and ice amount, and the special exponents, which show the effects of altitude, contamination and ice, are various with the type of the insulator, kind of voltage, contamination degree and ice amount etc.