±800kV特高压直流受端分层接入方式下低端阀厅金具结构设计

特高压直流输电系统受端采用分层接入方式是我国未来电网亟待研究的课题,该方式下换流站阀厅内部金具表面电场计算及结构优化对换流站的整体设计具有重要的指导意义。为此建立±800k V特高压直流输电系统分层接入方式下的仿真模型,得出受端低端阀厅典型金具的电位分布;校核计算传统±800k V阀厅金具在分层接入电压激励下的表面电场分布,并以此为基础,提出一种适用于分层接入方式的±800k V阀厅金具设计方案,即电场分布较严酷的D侧B相避雷器均压环内侧倒角半径根据其最大场强值随倒角半径变化曲线增大至合适的数值,400k V出线均压环管径增大至90mm,其他部分保持不变。计算结果可为采用分层接入方式的特高压直流工程设计和建设提供数据支撑。

Structure Design of ±800kV UHVDC Receiving End Low Voltage Valve Hall Fittings for Hierarchical Connection

The pattern called UHVDC hierarchical connection to AC grid is a urgent topic in the future, and the calculation for surface electric field intensity on valve hall fittings will be of great guiding significance for the design of the converter station. For this reason, a full-size model for low voltage valve hall of ±800kV UHVDC receiving end in hierarchical connection was set up, and voltages on some key parts was obtained. The surface electric field intensity on typical fittings in low voltage valve hall was determined according to the voltage distributions. On this basis, a practicable method for ±800kV valve hall fittings design was proposed, in which the fillet radius of D side B phase arrester grading ring increased to the right value according to the curve that revealed the varying rules between the maximal surface electric field intensity and the fillet radius. As a result, the tube diameter of 400kV equalizing ring could increase to 90mm and other parts remained unchanged. The calculation results provided a data support for UHVDC hierarchical connection engineering design and construction.