±1100kV分层接入换流站短路电流计算及地网设计研究

The Calculation of Short-circuit Current and Research on Design of Grounding Grid in ±1100kV Converter Station with Hierarchical Connection

摘要:

短路电流计算及接地设计是工程设计的重要内容，对换流站的安全稳定运行具有重要意义。基于±1100kV分层接入的特高压古泉换流站，对各种短路电流进行了计算，并在考虑了避雷线、变压器中性点等对短路电流的分流作用后，计算了换流站的入地短路电流。根据入地短路电流计算结果，给出了换流站接地网设计方案及其安全性评价。对于分层接入的换流站，应对不同的交流母线，基于换流站各类运行工况计算不对称短路电流，并取最大值校验地网设计指标。

Abstract:

Short circuit current calculation and grounding design both are the important parts of engineering design, which is of great significance to the safe and stable operation of the converter station. In this paper, based on ±1100kV Guquan UHVDC converter station with hierarchical connection, different levels of short-circuit current have been calculated. After considering the shunting effect of short-circuit current via lightning shield wires and the transformer neutral point, the grounding fault current of converter station is calculated. According to the grounding fault current, design scheme of grounding grid for the UHVDC converter station and safety evaluation have been proposed. For converter stations with hierarchical access, the asymmetric short-circuit current should be calculated for different AC buses based on variant operating situations, and the maximum value of short-circuit current should be used to verify the ground grid design indicators.