Open AccessCharge transport and accumulation around the cone‐type insulator in SF 6 ‐filled 550 kV DC GIL
Author(s) -
Zhang Bo,
Guo Yujing,
Yao Yongqi,
Wang Zhijun,
Zhang Hao,
Jin Guangyao
Publication year - 2019
Publication title -
the journal of engineering
Language(s) - English
Resource type - Journals
ISSN - 2051-3305
DOI - 10.1049/joe.2018.8526
Subject(s) - insulator (electricity) , electric field , arc flash , high voltage , materials science , electric power transmission , voltage , surface charge , sulfur hexafluoride , electrical engineering , composite material , physics , engineering , quantum mechanics
The gas‐insulated transmission line (GIL) has the advantages of large transmission capacity, high operation reliability and environmental friendliness. It is suitable for the high voltage direct current (HVDC) power transmission of hydropower stations or nuclear power stations. However, due to the serious surface charge accumulation problem of the cone‐type insulator under DC, its flashover performance is reduced, which restricts the engineering application of HVDC GIL. In this study, a charge transport model of SF 6 gas and epoxy is established for a 550 kV cone‐type insulator and the charge accumulation characteristics of the concave and convex surfaces of the cone‐type insulator are obtained. Computational results show that the gas conductivity around the cone‐type insulator is not uniform due to the charged particles drifting under a constant electric field. Compared with the AC, the difference of the electric field distribution caused by charge accumulation under DC stress is analysed. Based on the established model, the influence of the gas ion‐pair generation rate and epoxy volume conductivity on the charge accumulation on the surface of 550 kV cone‐type insulator was studied. This study is helpful to further optimise the geometry and material properties of the cone‐type insulator and reduce the surface charge accumulation and critical area electric field to improve HVDC GIL insulation design.