Switching Surge Sparkover Characteristics of Air Gaps and Insulator Strings Under Practical Conditions

Sparkover characteristics of rod-rod gaps and insulator string by switching surge are presented under the following conditions: 1) With simultaneous application of switching surge voltages to both electrodes of a rod-rod gap. 2) With application of a switching surge voltage of the upper electrode in synchronizing to the peak of 50-cycle voltage which is continuously applied to the lower rod. 3) With surfaces of post insulator stacks and suspension insulator strings covered with snow or ice. 4) With surfaces of suspension insulator strings contaminated by salt.