直流输电换流阀系统表面电场分析与均压环设计

为避免直流输电换流阀塔结构放电，对阀塔结构设计了合适的均压环，该设计应用ANSYS软件建立换流阀屏蔽系统结构模型，采用伽辽金间接边界元方法分别对未加均压环的阀体结构与施加均压环的整体结构进行表面场强分析，具体分析了均压环的高度、位置、间距对阀箱体结构表面场强的影响，文中对不同的均压环设计方案进行比较，在满足一定约束条件下根据比较结果选择了合适方案，该方案下的均压环使阀箱体得到良好屏蔽且均压环无起晕现象。比较结果说明换流阀体结构外部均压环之间距离越大，阀箱体结构所对应的棱边中点场强越大，均压环的施加使阀箱体模型对应尖角部位表面场强大幅度减小且均压环高度越大，阀箱体尖角部位表面场强越小。

Surface Electric Field Intensity Analysis of Converter Valve System and the Design of Grading Ring for DC Transmission

The grading rings for valve tower in DC converter station are designed to avoid discharging in shielding system of DC converter valve for DC transmission. The structure model of shielding system is built by ANSYS software, and the surface electric field intensity for converter valve without and with grading rings is analyzed by using of Galerkin indirect boundary element method. Then the influences of height, position and distance between grading rings on surface electric field intensity of valve body structure are analyzed. By comparing design cases of different grading rings, the suitable scheme is concluded to meet constraint conditions. The surface electric field intensity of valve structure is reduced greatly with appropriate scheme and there is no corona on the grading ring either. The results show that the bigger the distance between grading rings around converter valve body structure is, the stronger the field intensity of midpoint on relevant edges is; the grading ring reduces the field intensity of relevant sharp corner for converter valve body structure greatly; the higher the grading ring is, the smaller the field intensity of sharp corner for converter valve body is.