特高压SF_6气体绝缘套管内屏蔽结构研究

Investigation of Inner Shielding Structure for Ultra-high Voltage SF_6 Gas-insulated Bushing

为了研究特高压SF6气体绝缘套管内屏蔽结构的电场分布特性并制定合理的结构设计方案,通过对特高压SF6气体绝缘套管进行有限元电场分析,研究了边缘效应和结构参数对内屏蔽电极表面电场的影响。在此基础上,针对仅通过控制电极表面电场进行内屏蔽结构设计的局限性,研究了SF6局放起始电场强度对内屏蔽结构设计的影响。结果表明:内屏蔽电极边缘外形对电极边缘电场强度影响较大,而对电极中部电场强度影响较小,因此进行内屏蔽结构设计需要考虑边缘效应对电极表面电场的影响,将边缘外形设计和电极尺寸设计分开进行;此外,边缘外形对边缘SF6局放起始电场强度影响较大,在进行边缘外形设计时需要综合考虑表面电场强度和局放起始电场强度的影响。

In order to research electric-field distribution characteristics of inner shielding structure for UHV SF6 gas-insulated bushing and to make a reasonable plan for structure design, we investigated the influences of edge effect and structure parameters on surface field strength of inner shielding electrodes by finite-element electric-field analysis of UHV SF6 gas-insulated bushing. Furthermore, focusing on the limitations in inner shielding structure design by suppress- ing surface field strength, we investigated the influence of SF6 partial discharge inception field strength on inner shielding structure design. The results show that the edge shapes of inner shielding electrodes have a significant impact on edge field strength, but have little impact on middle field strength. Hence, the influence of edge effect should be considered in inner shielding structure design, and then the design of edge shapes and electrode sizes should be carded out separately. Moreover, the edge shapes have a significant impact on edge SF6 partial discharge inception field strength, and then the surface field strength and partial discharge inception field strength should be synthetically considered in edge shape de- sign.