Discharge or leakage current of ice accreted insulators at close to flashover voltage in high conductivity fog

Ice accretion on the lower shed surfaces of a vertical string of two standard suspension insulator units was artificially conducted. The accreted ice was hard time with a density of 0.90 g/cm/sup 3/. The conductivity of melted water from the ice was approximately 300 /spl mu/S/cm. During icing, the string was energized at 10 kV/unit. A withstand voltage test was conducted using the up-and-down method at a temperature of 0/spl deg/C in the cold room after icing and after 15 minutes fogging. The conductivity of the artificial fog was 2000 /spl mu/S/cm. Clean and contaminated insulators with salt deposit densities of 0.01 and 0.03 mg/cm/sup 2/ were tested. Discharge or leakage currents at voltages near the point of flashover were influenced by the fog and contamination levels.