6 / 2022-02-17 21:07:04

The influence of water permeation on the chalking of HTV silicone rubber

composite insulator,chalking,water permeation,aging

Chalking is a typical feature of the aging of silicone rubber based composite insulators, which could seriously damage the surface flashover strength. Based on the operation experience and experimental results, the chalking of silicone rubber is closely related to high temperature and high humidity. However, previous research focuses mainly on the water permeation process at room temperature, leaving the influence of temperature unrevealed. Considering that the evolution of water permeation is very slow in actual conditions, the samples are heated in water bath to accelerate the process in this paper. The evolution of weight and physicochemical properties of HTV silicone rubber is investigated. And the correlation between material chalking and water permeation is revealed. The results suggest that the transition layer of chalking layer is more loosened with various holes, resulting in the quicker absorption of humidity compared to pristine sample. Besides, High temperature would accelerate the humidity absorption of sample, and some components of sample might exfoliate during the water bath. Moreover, if considerable components exfoliate while the water absorption has already get saturated, the sample weight could decrease during the water bath.