Abnormal temperature rise and discharge characteristics of decay-like composite insulators

Abstract In recent years, there have been multiple incidents of fracture faults caused by the deterioration of composite insulators in China, seriously threatening the safe operation of the power system. This article takes a 500 kV decay-like composite insulator collected from the operation site as the research object, conducts visual inspection and analysis of its shed and core rod degradation status, and tests its infrared temperature rise and ultraviolet discharge distribution under power frequency operating voltage and related electrical parameters. Finally, an electric thermal coupling finite element model is established to analyze its discharge and tem-perature rise mechanism. The research results found that the infrared temperature rise characteristics and ultraviolet discharge characteristics of decay-like composite insulators can reflect their degradation status. As the testing distance increases, the measured infrared temperature rise gradually decreases. The distortion of dielectric parameters and the decrease in insulation resistance have caused partial discharge and abnormal temperature rise of decay-like insulators. In addition, compared to ultraviolet imaging detection, infrared temperature measurement can better reflect the internal defects of decay-like composite insulators and is less susceptible to interference from unrelated discharges around them.