3维复合分层土壤模型下竖直分层土壤对地表电位影响  

Effect of Vertical Soil Layer on Earth Surface Potential Under Three-dimensional Combined-layer Soil Model

作　　者：李文峰[1] 杨洪耕[1] 徐方维[1] 

机构地区：[1]四川大学电气信息学院,四川成都610065

出　　处：《四川大学学报（工程科学版）》2012年第5期161-167,共7页Journal of Sichuan University (Engineering Science Edition)

基　　金：国家自然科学基金资助项目(51077095)

摘　　要：如何构造适当的土壤模型来定量计算大尺度范围内地表电位分布一直是直流偏磁研究中尚未有效解决的难题,针对于此,提出了一种任意多层土壤模型:3维复合分层土壤模型,用复镜像法推导出点源处于任意分层时格林函数的一般解析解。基于该模型,分析了直流单极大地方式运行时竖直土壤分层,包括土壤电阻率、层厚、层深和位置对地表电位分布的影响,并与水平分层和2维复合分层土壤模型下情况进行了比对研究。结果表明,不同竖直分层土壤参数变化对地表电位分布带来不同程度的影响,在精确计算直流接地极周围地表电位时应考虑竖直分层土壤情况的复杂性;3维复合分层土壤模型可以比水平分层和2维复合分层土壤模型更加准确地模拟实际土壤,基于3维复合分层土壤模型可以更加准确计算出地表电位,该模型和结论进一步为直流接地极附近变电站选址提供理论参考。One of the challenges that hasn＇t been solved effectively in the study of direct current（DC） bias is how to establish the proper soil model to calculate the earth surface potential（ESP） accurately in large scales.In order to solve this problem,a soil model named as three-dimensional combined-layer soil model（TDCM） in which the layered soil might have any number of layers was introduced.Complex image method was applied for the derivation of the Green＇s function of this model,and the general analytical solution was derived when the source point was in any soil layer.Based on the model,the effect of the parameters of vertical medium layer,including resistivity,thickness,depth,and location,on the ESP was investigated when a high-voltage direct-current（HVDC） system used earth as its current return path.Besides,the results were compared with that of horizontally multilayer soil model（HMSM） and two-dimensional heterogeneous structure soil model（HSSM）.It was found that the different soil parameters have different effect on the ESP distribution,so the complexity of vertical soil layers should be considered in calculating the ESP.Moreover,the actual soil is able to be modeled by TDCM more accurately than HMSM and HSSM,and the ESP is able to be calculated more accurately based on the proposed model.The model and the results are useful for selection of substations near the HVDC ground electrode.

关 键 词：3维复合分层土壤模型 格林函数 地表电位 直流偏磁 

分 类 号：TM12[电气工程—电工理论与新技术] TM723