Flashover Tests of Insulators Covered with Ice or Snow

Several types of insulator strings covered with ice or snow were tested for ac, dc, and switchings impulse voltages. Reductions of flashover voltage were noted for all voltage types. These reductions were more acute on ice or snow covered insulator strings than on salt contaminated strings when deposits of salt were light. In cold regions, the characteristics of ice or snow covered strings are important factors in deciding the number of insulator units on transmission lines.