±800kV换流变压器阀侧电容式直流套管电场分析

Electric Field of Capacitive DC Bushing at ±800kV Converter Transformer Valve Side

为研究特高压直流套管的绝缘性能,建立了±800 kV复合电容式套管有限元模型,用ANSOFT分析软件对内采用绝缘环氧树脂绝缘纸和外绝缘采用高温硫化硅橡胶外套制造的复合电容式套管进行二维电场分析,获得特高压直流套管内部精确场强分布和电位分布。该结果表明:套管内部环氧树脂中的屏障强迫了电位分布,使法兰附近的电场分布均匀,却造成法兰顶端等位线发生剧烈变化,径向电位梯度大;法兰部分与高温硫化硅橡胶伞裙的接连处电场强度最大,最大值达3.44 MV/m,在特高压直流运行时最易产生闪络,是必须注意的问题。

In order to study insulation performance of ultra-high voltage DC bushing, this paper establishes a finite element model for ±800 kV composite capacitor bushing and uses ANSOFT analysis software for 2D electric field analysis on the composite capacitor bushing which uses epoxy resin insulation paper for internal insulation and high-temperature vulcanizing silicone rubber coat for external insulation. It obtains precise electric field strength distribution and potential distribution inside the ultra-high voltage DC bushing. Results indicate the epoxy resin barrier inside the bushing forces potential distribution that not only causes homogeneous distribution of electric field near the flange but also make equipotential lines on the top of flange change greatly and gradient of radial potential large. It also discovers electric field at the joint of flange and high-temperature vulcanizing silicone rubber umbrella skirt is the most intensive and the maximum value is 3.44 MV/m. In addition, it points out to pay attention to one problem of flashover at the moment of ultra-high voltage DC operation.