Flashover of composite insulators without hydrophobicity under heavy ice and the secondary contamination conditions

Some improvement on the icing flashover test procedures by taking into account the combined influences of the heavy ice accumulation was made. The test results demonstrated that the icing flashover voltages of the composite insulators with secondary contamination gave considerably lower values than the other two types of flashover voltages, namely the contamination flashover voltage obtained in the conventional clean-fog and the icing flashover voltage without secondary contamination, all the insulators being pre-contaminated with the same degree of equivalent salt deposit density (ESDD).