Study on decay-like fracture of 500 kV composite insulators: Infrared, ultraviolet and electric field distribution detection.

The power outage caused by decay-like fracture of composite insulators significantly impacts the power grid. In this paper, a decay-like fractured insulator of 500 kV transmission line is taken as a research object. The detailed observation of core rod and silicone rubber housings, discharge results, temperature rises, and electric field distribution are obtained. (a) The fractured insulator has abnormal heating on the exposed core rod and sheath surface, and the ambient temperature and humidity significantly influence the temperature rise. (b) It is proposed that one of the most obvious characteristics of decay-like insulator is abnormal temperature and temperature rise (such as T > 50°C, ΔT > 30 K). (c) Under the same conditions, temperature rises, electrical discharge, and electrical field strength of decay-like insulator are higher than those of other insulators, and the discharge at the bare core rod is intense. (d) The electric field strength distribution and discharge distribution of decay-like insulator are different from other aging and new insulators. However, the measurement results are significantly affected by test conditions. Therefore, it is difficult to determine whether the composite insulators are decay-like using electric field distribution and UV measurement on site. [ABSTRACT FROM AUTHOR]