Analysis of the Initial Aging Point and Development Process of A Pre-decay-like Aged Insulator

Decay-like aging of composite insulators is difficult to track and predict, seriously jeopardizing the operation of power systems. Early diagnosis of decay-like aging is important for preventing accidents. Taking an insulator abnormal heating failure as an example. Through tests such as leakage current, partial discharge, water diffusion, industrial CT, SEM, FTIR, the initiation point and development process of aging are restored, and it is determined that the heating phenomena in this case is an early manifestation of decay-like aging. The aging initiation point of the insulator is a vulcanization defect at the skirt-housing interface, the aging spreads and penetrates the housing, causing the failure of rod-housing interface. Eventually, decay-like aging will occur. The study also found that this batch of insulators is substandard, including the uneven mixed filler and suboptimal RTV bonding. This article provides a detailed case analysis for insulator abnormal heating. Assist manufacturers and power grid operators in strict product quality control to prevent accidents.