Influence of Contamination Characteristics on Flashover Behavior of Composite Insulator Surfaces

ABSTRACT With the continuous growth in global electricity transmission demand, contamination flashover on high‐voltage insulators has become a critical threat to grid stability, particularly, in rapidly industrializing regions. Although numerous studies have addressed the mechanisms and prevention strategies of flashover, quantifying the correlation between pollution and flashover occurrence, as well as establishing a scientific basis for effective prevention and maintenance strategies, remains highly important. This study investigates the flashover mechanism of composite insulators under polluted conditions, with a focus on the effects of contaminant composition, wetting behavior, and material properties. Through experimental measurements of the equivalent salt deposit density (ESDD), it was found that surface conductivity is highly sensitive to humidity and pollutants such as soluble salts. Using an optimized artificial contamination method, natural pollution accumulation processes were simulated, and the degradation of silicone rubber sheets under multiple flashover events was evaluated. The results indicate that the flashover voltage decreases significantly with increasing pollution severity and cumulative discharge events, while material damage intensifies with higher contamination levels. Molecular‐level analysis further reveals the chemical degradation pathways and structural changes induced by flashover.