Optical Imaging Technology Application in Transmission Line Insulator Monitoring: A Review

Insulators play a crucial role in electric power systems by isolating high-voltage currents and supporting conductors. However, insulators exposed to outdoor conditions for extended periods are susceptible to faults caused by contamination, aging, and damage, leading to flashovers that may result in grid outages and economic losses. Accurate assessment of insulator condition is paramount for the safe operation of power systems. Noncontact monitoring methods, which do not interfere with the normal operation of the power system, have become mainstream in insulator condition monitoring, contrasting with traditional contact-based detection. Among these methods, optical imaging technology has garnered significant attention due to its noncontact, nondestructive, high sensitivity, and intuitive characteristics. Optical imaging technology captures reflections, transmissions, and absorptions in different spectral bands to gather information about the surface and interior of insulators, thereby determining the type of faults they may exhibit. This article reviews optical imaging detection methods applied in the field of insulator condition assessment, including infrared thermography, ultraviolet imaging, visible light imaging, and some promising optical monitoring technologies. Additionally, the advantages and limitations of these methods under various insulator fault conditions are analyzed, and challenges in industrial applications are discussed. The purpose of this article is to provide a comprehensive and systematic reference for the application of optical imaging technology in insulator condition assessment, aiming to enhance the efficiency and safety of power system operation and maintenance.