Improvement of Insulation Performance of a Porcelain Long-Rod Insulator under Contaminated Conditions

Abstract

The higher contamination flashover voltage performance of a transmission line polymer insulator has been shown to be attributable not only to its surface hydrophobicity but also to its configuration. A larger ratio in the shed to core diameter of the transmission line polymer insulator brings about higher surface resistances in its individual trunks, and therefore the voltage applied to the entire insulator can be divided and allotted to these trunks, resulting in a higher flashover voltage. We expected a similar effect by applying a silicone rubber coating having hydrophobicity only to all the trunk surfaces of a porcelain long-rod insulator. We tested by the clean fog method and confirmed only about a 10% improvement. In this paper, the same such effect was evaluated by the salt fog test method, which confirmed a significant improvement. The detailed investigation results are presented.