Process and Modeling of Arc on a Snow-Covered Insulator

Snow and ice accumulation on high voltage equipment such as insulators and conductors may cause problems of mechanical and electrical origins. One of the most serious problems under snow and ice accumulation is insulator flashover, which has been studied to some extent by researchers in several cold climate countries. In this paper, the AC flashover process and electrical behavior of snow deposited on a polymer insulator is the subject of study. Moreover, a mathematical model for simulating the behavior of snow under alternating voltage is presented. For this, two experimental setups were developed and from the voltage-current characteristics of snow, which were measured from several different tests, it was found that the voltage across snow and the leakage current flowing through the snow-covered insulator are almost in the same phase, which it means that a snow-covered insulator behaves as a pure resistance. The resistance of snow is not linear, as it decreases as voltage increases. An increase in length of the snow cover results in an increasing in flashover voltage, but increasing the density and conductivity of water melted from snow yields the inverse effect and causes a sharp decrease in flashover voltage