Study on Raindrop Dynamic Behaviour and Its Impact on Insulator Flashover Characteristics Under Airflow Synergy

ABSTRACT The synergistic effect of airflow on rainfall behaviour significantly impacts the flashover probability of insulators. This study combines experiments and simulations to investigate the influence of raindrop dynamic behaviour, shed structures and rainfall conditions on flashover characteristics under airflow conditions. High‐speed cameras capture the dynamic behaviour of raindrops along the shed eave and their impact on the development of flashover. Meanwhile, finite element simulations analyse the role of shed structures in regulating airflow characteristics, raindrop dynamic behaviour and electric field distribution. The results indicate that airflow‐induced changes in raindrop behaviour exacerbate inter‐shed electric field distortion. Raindrop stretching, fragmentation, recombination and bridging behaviours accelerate the formation of conductive paths, significantly influencing arc generation, expansion, strengthening, drifting and extinction. Roof insulators with larger shed spacing and wider shed skirts demonstrate better resistance to rain‐induced flashover by suppressing raindrop accumulation and alleviating electric field distortion. This study reveals the synergistic mechanism among raindrop dynamic behaviour, electric field distortion and flashover characteristics, offering optimisation guidelines for insulator selection under extreme rainfall conditions for high‐speed trains.