“…With the continuous promotion of the west-east power transmission project and the acceleration of regional power and energy interconnection, gas-insulated transmission lines with their advantages of large transmission capacity, long transmission distance, and good environmental compatibility have been put into operation in major power transmission constructions such as Tianshengqiao hydropower station, Xiluodu hydropower station and Sutong GIL integrated pipeline corridor in China Statistics show the reasons for the failure of GIL equipment, among which mechanical failures account for 2/3 [1]- [2]. Because GIL equipment applications are mostly extra-high voltage and closed structures, once a failure occurs, it will cause huge economic losses, so its fault diagnosis is of great significance to the safe transmission of electric energy and stable operation of the power grid [3]- [4]. Gas-insulated metal-enclosed transmission lines are an important supplement to overhead transmission methods under restricted geographical or environmental conditions and are widely used in China because of their significant advantages, such as high transmission capacity, low losses, environmental independence, high operational reliability, and space-saving [5]- [6].…”