多层土壤结构下直流偏磁电流分布计算研究  

Research on calculation of DC-biased current distribution under multi-layer soil structure

作　　者：石瑶 朱姝婕 陈宇晨[2] 徐宁 Shi Yao;Zhu Shujie;Chen Yuchen;Xu Ning(School of Electrical Engineering,Shanghai University of Electric Power,Shanghai 200090,China;Shanghai University of Engineering Science,Shanghai 201620,China;State Grid Anhui Electric Power Co.,Ltd.,Hefei 230022,China)

机构地区：[1]上海电力大学电气工程学院,上海200090 [2]上海工程技术大学,上海201620 [3]国网安徽省电力有限公司,合肥230022

出　　处：《电测与仪表》2020年第14期28-33,共6页Electrical Measurement & Instrumentation

摘　　要：针对地表电压预测不准确而造成直流偏磁电流评估偏差较大的问题,文中基于场源关系下的拉普拉斯方程和泊松方程,通过数学解析法结合土壤边界条件求解出多层土壤的地表电位表达式。通过分析3种土壤模型下的地表电位分布曲线,确定了合理的土壤模型。在此基础上通过场路直接耦合的方法建立了变压器中性点直流量评估模型。基于.NET平台对上海市某地区电网数据实现了地表电压分布预测和接地极附近变压器中性点直流偏磁电流的计算,并将计算结果与CDEGS软件的仿真结果进行对比,验证了所提方法的有效性与准确性。With the inaccurate prediction of surface voltage,the assessment of the DC-biased current may deviate greatly from the actual value.In view of the problem,the surface potential expression of multi-layer soil is obtained by combining the soil boundary conditions with the mathematical analytic method,based on Laplace equation and Poisson equation under the relationship of field source.Then,the reasonable soil model is determined by analyzing the surface voltage distribution curves of three soil models.On this basis,the transformer neutral point DC evaluation model is established by the method of direct field-circuit coupling.Finally,the surface voltage distribution prediction and the DC-biased current calculation of transformer neutral point for a regional power grid in Shanghai are realized based on.NET platform.The validity and accuracy of this model are proved by comparing the calculation results with the simulation results of CDEGS software.

关 键 词：直流偏磁 地表电位 中性点直流 水平分层土壤模型 场路耦合 

分 类 号：TM744[电气工程—电力系统及自动化]