变电站站址土壤结构分析

Soil structure analysis for substation sites

土壤分层结构模型是进行接地系统分析设计的基础。采用电磁场理论推导出点电流源在多层土壤条件下的地表电位分布公式 ,并以此为基础推导出用 Wenner法测量得到的视在电阻率与极间距的关系。通过引入非线性目标函数 ,将求土壤参数问题转化为求目标函数的极值问题 ,选用适当的优化计算方法得到与理论值吻合较好的土壤结构参数。所研制的土壤分层软件在实际变电站站址土壤结构分析中得到了应用 。

The multi layer soil structure model is used to design grounding systems of substations and power generating stations. The potential distribution of the ground surface due to a point current source is derived using electromagnetic field theory. The relationship between the apparent soil resistivity measured by the Wenner four poles method and the measurement pole span is also obtained. A nonlinear target function is introduced to transform the problem from the analysis of structural parameters to calculating the limited value of the nonlinear target function. After thorough research, one suitable method is used to calculate the soil structure parameters. The analysis software is applied to calculate actual substation sites' soil parameters, and the result in good agreement with the actual values.