Analysis of AC Pollution Flashover Arc Path for Composite Arrester-Combined Insulator

Under the backdrop of “West-to-East Power Transmission,” the high-altitude environment has led to frequent lightning strike accidents in the external insulation of power systems. Coupled with the traditional risk of pollution flashover, the combined application of insulators and arresters has emerged as a solution. This paper focuses on 10 kV composite arrester combined insulators, analyzing four possible arc paths based on their equivalent circuits. Subsequently, artificial pollution flashover tests are conducted. By fitting the relationship between the pollution flashover voltage of the insulating part of the combined insulators and the equivalent salt deposit density, the consistency of its insulation characteristics with those of conventional insulators is verified. Finally, the arc paths of the insulator and arrester parts are statistically analyzed separately. The results show that under low contamination levels, the arc probability in the metal electrode gap of the insulator part reaches 70.6%, and the operating rate of the arrester can reach 80.0%, indicating that the functions of the combined insulator are fully utilized. However, under high contamination levels, the arc probability in the metal electrode gap drops to 50.0%, and the operating rate of the arrester decreases to 17.9%. This indicates that both the arc-drawing ability of the metal electrodes and the functions of the arresters are inhibited.