Live‐Line Work on High‐Voltage Transmission Overhead Lines: From FRP Flashover to Air‐Gap Breakdown Physics and Emerging Technologies

ABSTRACT This paper presents a comprehensive review of live‐line work on high‐voltage transmission overhead lines, with a focus on insulation performance, air‐gap breakdown and discharge physics under realistic operating conditions. This review primarily covers journal publications from approximately 2014 to 2026, with emphasis on recent developments in the field. Despite the critical importance of live‐line maintenance for power system reliability, the number of peer‐reviewed journal studies remains relatively limited, and this work aims to consolidate the majority of available contributions within this period. Key topics include flashover mechanisms of fibreglass‐reinforced polymer hot sticks under cold and freezing conditions, physics‐based modelling of long air‐gap breakdown under switching‐impulse voltages and the influence of tower geometry, worker configuration and hybrid AC/DC systems on insulation performance. In addition, multi‐worker interaction, floating‐conductor effects, potential transfer mechanisms and high‐altitude conditions are examined. Fundamental discharge processes, including streamer inception, streamer‐to‐leader transition and leader propagation, are reviewed to establish a unified physical framework. Collectively, the reviewed studies demonstrate that live‐line insulation performance is governed by coupled electrostatic, thermal, environmental and geometric effects. This review provides a consolidated reference for the field, identifies the need for integrated multiphysics modelling approaches to improve safety criteria, standards development and minimum approach distance determination, and discusses emerging developments in helicopter‐assisted maintenance, advanced access techniques, monitoring and diagnostic technologies, artificial intelligence‐assisted tools and digital approaches that may contribute to safer and more efficient live‐line maintenance in future power systems.