Investigation and corroboration of a novel method to estimate the hydrophobicity of composite insulators

Reliability is the most important property for insulators applied in electric power. As for composite insulators, hydrophobicity is a valuable and significant property in practical service. In this paper, based on dynamic contact angle measurement, a novel method to estimate the hydrophobicity of composite insulators is suggested. Using the new criteria, the hydrophobicity of composite insulators is estimated by receding contact angle and advancing contact angle respectively, and the hydrophobicity classes are divided into five levels: E-, G-, S-, P-, and F-class. A further investigation using ATR FT-IR, TGA, and SEM is processed. All results confirm that the new criteria not only reveal the hydrophobicity of insulator surface but also relate chemical structure and microphase components to their surface, the aging status of composite insulators turn to deteriorate with the decreasing of hydrophobicity from E- to F-class. The new criteria are reasonable and flexible for hydrophobicity estimation of composite insulators; they also reveal the aging status of practical insulators, which is very significant for reliability estimation in practical application.