Abstract The grounding devices guarantee the safe and stable operation of the power system and electrical apparatus. The accurate calculation of grounding parameters lays the theoretical basis for the design and maintenance of grounding devices. The existing calculation methods for grounding parameters in layered soils are mainly based on the complex image method with global sampling. On the one hand, the global sampling method cannot accurately approximate the integral kernel of Green’s function in complicated horizontally layered soils with many thick layers, which would cause large calculation errors or divergent results. On the other hand, the number of complex images is often twice the number of soil layers, which would cause the calculation amount blindly increases linearly with the number of soil layers. To solve the above disadvantages, this paper proposes a novel segmented sampling numerical calculation method (SSNCM) for grounding parameters in horizontally layered soils. The segmented sampling calculation method of Green’s function based on the extreme points of the integral kernel function of Green’s function in layered soils and the unequal potential calculation method for grounding devices in layered soils are studied to form the SSNCM. The cases study on 3 typical grounding devices are calculated by the SSNCM and the software CDEGS. The results show that the SSNCM has better calculation efficiency and adaptability for different layered soils, and can provide a theoretical foundation for grounding parameters analysis and grounding devices design.

中文翻译：

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水平多层土接地参数分段采样数值计算新方法

摘要 接地装置是电力系统和电气设备安全稳定运行的保证。接地参数的准确计算为接地装置的设计和维护奠定了理论基础。现有的层状土壤接地参数计算方法主要是基于全局采样的复图像方法。一方面，全局采样方法不能准确逼近复杂水平层状土层多厚的格林函数的积分核，导致计算误差大或结果发散。另一方面，复杂图像的数量往往是土层数的两倍，这会导致计算量随土层数线性增加。为解决以上缺点，本文提出了一种新的分段采样数值计算方法（SSNCM），用于水平层状土壤中的接地参数。研究了基于层状土壤格林函数积分核函数极值点的格林函数分段采样计算方法和层状土壤接地装置不等电位计算方法，形成了SSNCM。通过SSNCM和CDEGS软件计算了3种典型接地装置的案例研究。结果表明，SSNCM对不同层状土壤具有较好的计算效率和适应性，可为接地参数分析和接地装置设计提供理论基础。