水电站主变的直流偏磁的评估与抑制  

Evaluation and mitigation for DC bias in Hydropower plant

作　　者：张露[1] 潘卓洪[1] 雷鸣 谭波[1] 张曾[1] 文习山[1] 

机构地区：[1]武汉大学电气工程学院,湖北武汉430072 [2]洛阳市供电公司,河南洛阳471009

出　　处：《电机与控制学报》2010年第7期29-35,共7页Electric Machines and Control

基　　金：国家重点基础研究发展计划(973)(2009CB724500)

摘　　要：对水电站变压器直流偏磁的问题建立了评估模型并开发出软件计算,通过实测与仿真的对比说明模型有效性,并以锦屏二级水电站为例对水电站的建设和运行提出了建议。另外,结合水电站的实际情况分析了不同抑制措施的特点,重点分析了电流注入法的原理和仿真模型,通过监测数据验证了电流注入法模型的有效性,并定量分析了土壤电阻率和补偿距离对中性点注入电流时补偿度的影响。仿真计算和实际应用情况表明:电流注入实质上起补偿变电站间母线电位差的作用,土壤电阻率增大或者补偿距离减少会导致注入电流大小增加,补偿度会降低,在一般情况下补偿度小于0.6。电流注入法不改变中性点状态,节约电站空间,可以安全有效地抑制大型水电站内所有变压器的直流偏磁。The evaluation model for transformers’ DC bias in hydropower plant under HVDC ground return operating model was presented.The developed software based on this model was established.Comparision between mesured value and calculated result proved the effectiveness of the model.Current injection meth-od was analyzed and was stressed on the ways of surpress DC bias.Take JingPing hydropower plant for ex-ample,suggestion on construction and operation of the hydropower plant were presented.With the practical condition of hydropower plant,different DC bias mitigation methods were analyzed.Monitoring data verified the effectiveness of the current injection method and the impact of soil resistivity and compensation distance on compensation degree was quantitatively analyzed.Simulation and application of the method show that current injection actually functions as compensation of potential difference to the bus of substation.Increase in soil resistivity demand or decrease in compensation distance lead to the increase in injection current.But it leads to lower compensation degree and the compensation degree usually bellows 0.6.The most advan-tage of current injection method is to keep neutral unchanged and save space of station.Only ones set of the equiment can safely supress the transformer DC bias in hydroplant.

关 键 词：直流输电 变压器 直流偏磁 电流注入法 

分 类 号：TM721.1[电气工程—电力系统及自动化] TM622