换流变压器编组和受端电网结构对其直流偏磁的影响研究  

Research of Converter Transformer Marshalling and Receiving-End Grid Structure's Effect on Converter Transformer DC Bias

作　　者：刘连光[1] 闫旭东[1] 马成廉[1] 魏恺[1] 张燕秉[2] 

机构地区：[1]华北电力大学电气与电子工程学院,北京市昌平区102206 [2]国家电网公司直流建设分公司,北京市西城区100052

出　　处：《电网技术》2016年第1期322-327,共6页Power System Technology

基　　金：国家自然科学基金项目(515770607)~~

摘　　要：溪洛渡—浙西±800kV直流输电试运行期间,金华换流站的换流变压器发现了严重的直流偏磁问题。针对溪洛渡—浙西UHVDC的受端电网结构和金华换流站4组换流变,建立了考虑换流变编组和受端电网结构等影响因素的直流偏磁电流计算模型,运用比较分析法和节点电压法计算了换流变的直流偏磁电流,研究了换流变编组和受端电网结构对换流变直流偏磁的影响。研究的结果表明:当1/2单极大地满负荷运行时换流变的直流偏磁最严重,换流站500kV母线馈线长度、回路数及所连变电站距接地极的距离是影响换流变直流偏磁严重程度的主要因素,建议在UHVDC的受端电网构成和结构的规划与设计中考虑减小流入换流变直流电流的措施。During the operation of Xiluodu-Zhexi ±800 kV HVDC transmission project, a serious DC bias problem arose for converter transformers of Jinhua converter station. Based on Xiluodu-Zhexi UHVDC receiving-end grid structure and four groups of converter transformers of Jinhua converter station, we establish a calculation model for DC bias current, taking into consideration factors such as the converter transformer marshalling operation mode and the receiving-end grid structure. Using comparative analysis and node voltage method, the converter transformer DC bias current is calculated, the influence of different converter transformer marshalling and receiving-end grid structure on converter transformer DC bias is analyzed. The research results show that, the most severe DC bias occurs in converter transformers when the converter is operating at 1/2 unipolar ground at its full capacity, and the main factors affecting DC bias severity are the length of the 500 kV bus feeder, its loops number and its connected station’s distance to the grounding electrode. In the planning and design of receiving-end grid composition and structure, the measure to reduce the direct current of converter transformers should be considered.

关 键 词：换流变编组 受端电网结构 直流偏磁电流 

分 类 号：TM721[电气工程—电力系统及自动化]