分层土壤中接地装置冲击散流特性的有限元分析模型

发布时间：2018-09-12 11:43

【摘要】：冲击电流在分层土壤中的散流过程具有明显的非线性变化特征,从电磁场理论出发,建立了分层土壤结构中接地装置冲击特性分析的有限元模型。在非线性过程的分析中考虑了传导和位移电流,准确地反映了冲击散流的物理过程;针对接地导体与土壤分界面、土壤分层界面的电阻率突变而造成有限元计算不易收敛的问题,采取了具有连续偏导数的平滑阶跃函数进行过渡的方法;在将无限散流空间变换为有限计算区域的问题上,提出了分层结构土壤的几何坐标变换方法,既减少了计算量又保证了计算准确度,并将仿真计算结果与试验结果进行对比分析。结果表明该模型能较好地模拟分层土壤结构中,土壤电离不均匀性和放电通道随机性带来的非线性变化问题,验证了模型的有效性。
[Abstract]:The scattering process of shock current in stratified soil has obvious nonlinear variation characteristics. Based on the theory of electromagnetic field, a finite element model for analysis of impact characteristics of earthing devices in layered soil structure is established. In the analysis of nonlinear process, conduction and displacement current are taken into account, which accurately reflects the physical process of shock dispersion. The problem that finite element calculation is not easy to converge due to the resistivity abrupt change of soil stratified interface, the method of transition of smooth step function with continuous partial derivative is adopted, and the infinite scattered flow space is transformed into a finite computational region. A method of geometric coordinate transformation for layered soil is proposed, which not only reduces the amount of calculation but also ensures the accuracy of calculation. The results of simulation and experiment are compared and analyzed. The results show that the model can well simulate the nonlinear variation caused by soil ionization inhomogeneity and discharge channel randomness in layered soil structure, and the validity of the model is verified.
【作者单位】：广西电网公司电力科学研究院;重庆大学电气工程学院;
【基金】：国家自然科学基金项目(51107153)~~
【分类号】：TM862

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