Mechanism analysis on hydrophobicity decrease of operating silicone rubber insulators

Through a series of on-site hydrophobicity-measuring tests for the silicone rubber insulators operated in Henan electric power grid of China, some insulators were found having the bad hydrophobicity performance. The objective of this paper is focused on the mechanism analysis of the hydrophobicity decrease of these insulators through a series of laboratory tests. As a comparison, some new samples were also investigated. Firstly, the hydrophobicity of the tested insulators was measured using the HC method before and after washing the contamination layer away. In addition, the scanning electron microscopy (SEM) and the attenuated total reflection infrared spectroscopy (ATR-FTIR) were also used to analyze the effect of aging on the hydrophobicity of the operating insulators. The test results show that the difference of the hydrophobicity performance of silicone rubber materials between the operated insulators and the new ones is negligible. The contamination deposition is the main factors causing the surface hydrophobicity decrease of these operating insulators. Some aging phenomena were found through SEM and ATR-FTIR tests. But the relationship between these aging phenomena and the hydrophocity decrease of the operated insulators was not found.