Detection Methods and Condition Assessment of High-Voltage Bushings: A Systematic Review

Abstract

As core connection components in power transmission systems, high-voltage bushings operate under extreme conditions for extended periods, including high voltage, high current, elevated ambient temperature, and intense mechanical loads. Under the combined effects of electrical, thermal, and mechanical stresses, internal discharge and overheating faults in bushings are particularly prominent, posing a serious threat to the safe and stable operation of ultrahigh-voltage AC/ultrahigh-voltage DC (UHVDC) power grids. As grid voltage levels and transmission capacities continue to increase, accurate detection and intelligent assessment of the operating condition of high-voltage bushings have become crucial for ensuring their reliable operation. However, most existing studies focus on individual detection methods but lack systematic comparisons and engineering applicability analyses of different technologies, making it difficult to guide the selection of on-site detection schemes. This article first reviews the typical structures and evolutionary history of high-voltage bushings and summarizes their typical faults and occurrence mechanisms. On this basis, this article reviews recent advances in six categories of fault detection and condition assessment technologies, including electromagnetic, thermal, acoustic, optical, chemical-composition analysis, and intelligent diagnosis methods, with emphasis on the applicable scenarios, technical advantages, and application limitations of each method. Finally, this article discusses in depth the main challenges faced by current technologies, including environmental interference, sample dependency, and difficulties in virtual–physical synchronization, and outlines key future research directions, aiming to provide theoretical guidance for real-time monitoring and intelligent diagnosis of high-voltage bushings.