交直流互联系统直流地表电位简易算式  

Study of the Simple Formula of DC Surface Potential in AC-DC Interconnected Large Power System

作　　者：任志超[1] 续建国[1,2] 张一坤[1] 甄威[3] 吴广宁[1] 

机构地区：[1]西南交通大学电气工程学院,成都610031 [2]山西电力科学研究院,太原030001 [3]四川电力科学研究院,成都610072

出　　处：《电工技术学报》2011年第7期256-263,共8页Transactions of China Electrotechnical Society

基　　金：中加国际科技合作项目(2009DFA72230)

摘　　要：直流接地极入地电流引起的偏磁问题威胁着交流电网的安全运行。基于大地典型三层结构,本文首先提出了一种求解直流地表电位的简易算式,表达形式简单,便于编程计算;其次,利用变压器中性点直流电流的现场实测值,列写节点方程,确定简易算式中的系数,通过比较计算值、仿真值和实测值,验证了该算式的可行性;最后,利用该算式预测了某超高压直流工程单极投运后可能引起的直流地表电位、跨步电压,评估了直流接地极入地电流在变电站的分流情况,指出部分站点可能需要采取相关防护措施。DC magnetic bias,caused by the current from the DC grounding electrode,threatens the safety of AC grid.At first,a simple and easy-to-use formula for calculating the DC surface potential was presented,which was based on typical three-layer soil structure.Secondly,in the verification, measured value of DC current of transformer neutral point was applied to decide the coefficient of the formula by editing nodal equation.Comparison of the calculated,simulation and measured value demonstrates high accuracy of the formula.Finally,DC current distribution in substations caused by DC grounding electrode was evaluated by predicting DC surface potential and step voltage in a HVDC with the formula mentioned above.Several substations were pointed out to take protective measures.

关 键 词：直流接地极 直流偏磁问题 直流地表电位 简易算式 变压器中性点直流电流 跨步电压 

分 类 号：TM723[电气工程—电力系统及自动化]