Surface Flashover in 50 Years: III. Extreme Environments and Industrial Challenges

ABSTRACT Modern high‐voltage electrical equipment operates in complex environments where surface conditions are subjected to multifaceted influences from electric fields, thermal gradients, contaminants, irradiation and other extreme environmental factors. Under high‐voltage conditions, surface flashovers frequently initiate at the gas–solid interface of insulators, jeopardising the operational reliability of industrial systems. To address flashover challenges in practical electrical equipment, this review systematically analyses the impact of environmental variables—including gaseous media, voltage waveforms, contaminants and high‐energy irradiation—on surface flashover characteristics. Subsequently, we comprehensively synthesise the mechanisms, contributing factors, suppression techniques and enhancement strategies for surface flashover in four critical equipment categories prone to this phenomenon: high pulsed power systems, spacecraft operating in vacuum environments, gas‐insulated switchgear/transmission lines (GIS/GIL) and outdoor insulators. The environmental dependencies of flashover behaviour in these systems are rigorously examined. Furthermore, to advance flashover prevention in next‐generation industrial applications, this study identifies 25 fundamental scientific questions and 25 technical questions to guide future research directions. By establishing an integrated theoretical framework and methodological foundation for engineering‐oriented flashover studies, this work provides actionable insights and mitigation approaches to enhance the surface insulation of modern industrial infrastructure.