特高压直流输电系统稳态运行时高端阀厅内部的电场分析

Analysis of Overall Electric Field in High-voltage Valve Hall End on Steady State of UHVDC System

为了确定特高压直流(UHVDC)输电工程阀厅内部整体电场及金具表面电场的分布情况,基于向家坝—上海±800kV UHVDC输电工程的实际参数,利用PSCAD对直流系统稳态运行情况进行了建模仿真,得到1个工频周期内高端阀厅内部关键电压点的瞬时对地电位值;利用ANSYS对送端换流站极Ⅰ的高端阀厅建立了1:1全尺寸模型,通过有限元分析法计算得到了阀厅内部金具表面的电场强度及空间电场分布云图。结果表明,稳态运行时阀厅内部金具表面的最大电场强度为16.73kV/cm,未达到起晕电场强度,符合阀厅电场强度的设计控制要求;阀厅内部金具表面及其附近的电场分布比较均匀,没有电场明显集中的现象。通过该研究,可掌握目前已投运的特高压直流输电工程高端阀厅内部的电场分布情况,同时为进一步确定阀厅内部电场的控制值打下了基础。

In order to confirm the electric field distribution in the valve hall and on the surface of fittings of ultra-high voltage direct current （UHVDC）, using parameters of Xiangjiaba-Shanghai ±800 kV UHVDC project, we established a simulation model though PSCAD, and obtained the instantaneous potential to ground at critical points in high-voltage valve hall end in steady state during one power frequency period. The finite element model of pole I in the hall, which was size-equally established in ANSYS, was also used to calculate and analyze the electrical field distribution and its cloud image on the surface of fittings and in the space. The results reveal that, the maximum electric field on the surface of fittings in steady state is 16.73 kV/cm, which is less than the value of corona inception and meets the requirements of design control of valve hall; meanwhile, the distribution of electric field on and around the surface of fittings is relatively uniform. It is concluded that through the proposed work, we can know the distribution of electric field in high voltage end valve hall of UHVDC projects quite well, and the control value of the electric field can be confirmed by the results.