Improvement of the DC voltage insulation efficiency of suspension insulators under contaminated conditions

The authors describe the results of the research and development on a suspension-type insulator having a DC contamination withstand voltage 1.25 to 1.3 times higher than that of the standard DC fog insulator, as measured by the fog-withstand or the clean-fog method. Also described are the withstand voltage characteristics of the suspension insulator contaminated with soluble materials and nonuniformly contaminated, simulating natural-field conditions. Design criteria taking these results into account are also discussed. >