AC Pollution Flashover Characteristics on Patterned Hydrophilic-Hydrophobic Surface

Abstract

Applying room temperature vulcanizing (RTV) coating on the surfaces of glass and ceramic insulators is a widely employed strategy for antipollution flashover. RTV coating peeling off is the most prominent problem during operation. This study designs an RTV infused regular circular indentations embedded coating structure (ECS). This structure enhances the coating’s adhesion per unit area, thereby reducing the probability of peeling off. To investigate the feasibility of ECS application in outdoor insulation, this article conducts comprehensive hydrophobicity tests and artificial pollution tests. The findings reveal that the polluted ECS exhibits overall hydrophobicity, and its antipollution performance is 4.5% higher than that of RTV. Furthermore, this article discusses the ECS’s pollution flashover mechanism. In the initial stage, according to the FEA model of ECS’s pollution layer, the nonuniform electrical stress and current density are the reasons why ECS forms multiple dry bands. Meanwhile, multiple dry bands induce multiarcs properties similar to those of RTV surfaces. For the arc development stage, this article proposes a model for multiarcs development applicable to hydrophobic surfaces. Calculation results show that the minimum current required for ECS’s nearby arcs merging is 3.5% higher than that of RTV. Hence, the probability of developing from multiarcs to the complete flashover is lower. In summary, ECS holds the potential to become a new insulator structure, offering a long-term solution to pollution flashover issues.