Analysis on heat source of abnormal temperature rise of composite insulator housings

In recent years, the local temperature rise of composite insulators has become a serious problem. In this paper, the temperature rise characteristics of the insulators at different humidity were studied at first in the laboratory. High humidity was found to be the prerequisite of temperature rise. Then the electrical characteristics of temperature rise area were analyzed. The housings of samples showed different surface currents under AC and DC electrical field. The temperature rise of the sample caused by the surface current was simulated and calculated afterwards. It was proved that the temperature rise of the housing was caused by the surface current. Finally, a temperature rise model of the housing was established. Dielectric loss in the surface layer of the silicone rubber induced by moisture is the primary factor that caused temperature rise on field-aged composite insulator housings.