水平层状土壤接地问题的理论推导与数值分析  

Theoretical Derivation and Numerical Analysis for Grounding Computation of Horizontal Multi-layer Soil

作　　者：潘卓洪[1] 张露[1] 谭波[1] 鲁海亮[1] 文习山[1] 

机构地区：[1]武汉大学电气工程学院,武汉430072

出　　处：《高电压技术》2011年第4期860-866,共7页High Voltage Engineering

基　　金：国家重点基础研究发展计划(973计划)(2009CB724500)~~

摘　　要：水平层状结构土壤格林函数的理论推导过程复杂且数值求解步骤繁琐。为降低理论难度和提高算法可靠性,把水平多层土壤接地问题等价为首层电阻率为无穷大的全空间层状土壤的情况,并根据分离变量法和全空间层状土壤的边界条件给出全空间任意层格林函数的通用理论表达式。通过对格林函数数值特性的分析提出了格林函数系数的智能采样方法,讨论了格林函数的数值求解方案。通过与接地标准软件CDEGS的对比算例表明该方法的正确性。算例表明,变电站的接地电阻与深度在地网对角线长度范围内的土壤存在较明显的关系,且高阻层较低阻层更能够屏蔽深层土壤。最后推导了垂直多层土壤格林函数的表达式,拓展了该方法的应用范围。Theoretical derivation complexity and numerical analysis complication are two main difficulties in Green＇s function method of horizontal multi-layer soil. In order to reduce theoretical difficulty and to improve reliability of algorithm, horizontal multi layer soil was equivalently taken as the full-space stratified soil with the first layer. Based on method of separation of variables and the boundary condition of full-space stratified soil, the generalized theoretical expression of Green＇s function of arbitrary layer was obtained. By numerical characteristic analysis of Green＇s function, the intelligent sampling method was proposed to obtain the dynamic waveform of the coefficient of Green＇ s function, and then numerical solution method of Green＇s function was discussed. Moreover, the validity of this method was checked by software CDEGS. The results show that grounding impedance is significantly decided by the soil above the depth of grid＇s diagonal line length, and the high-resistivity layer, compared to the low-resistivity lay er, can shield the deeper soil from grounding grid. This method is a universal method for horizontal or vertical multilayer soil.

关 键 词：水平多层土壤 垂直多层土壤 格林函数 分离变量法 复镜象法 数值计算 接地 

分 类 号：TM862[电气工程—高电压与绝缘技术]