一种考虑接地极选址及受端电网结构的偏磁电流减小方法

A DC Bias Current Reducing Method Considering Grounding Electrode Location and Receiving-end Grid Structure

基于受端电网的结构和接地极的位置对直流偏磁电流的影响,分别分析了交流电网各变电站不同联结方式下,换流站和相邻交流变电站在典型连接结构下的直流偏磁电流(DCBC)水平。分析了影响换流变压器和交流变压器DCBC值的因素,阐述了接地极选址及受端电网结构对变压器DCBC值的影响机理。考虑到受端电网结构和接地极的位置选择,提出了一种降低换流变压器和交流变压器的DCBC的方法。可从系统运行方式选择,接地极位置选择,电网结构规划设计等方面分析抑制DCBC的措施,建议在规划和设计阶段对换流变压器及交流变压器进行偏磁电流的防治。

Based on the influence of the receiving-end grid structure and the grounding electrode location on DC bias current,this paper analyzes the DC bias current(DCBC)level of the converter station and the adjacent AC substation in the typical connection structure under different connection modes of the AC substations.The factors affecting the DCBC value of converter and AC transformers are analyzed,and the influence mechanism of the grounding electrode location and the receiving-end grid structure on the transformer DCBC value is expounded.Considering the structure of receiving-end grid and the location selection of grounding electrode,a DCBC value reduction method for converter and AC transformers is proposed.The measures to suppress the DC bias current can be analyzed from the aspects of system operation mode selection,grounding electrode location selection,power grid structure planning and designing,etc.This paper proposes to prevent the bias current of the converter and AC transformer during the planning and designing stage.