In lightning discharge, the grounding systems' transient behavior is influenced by frequency-dependent effects. These effects are related to complex phenomena arising from the fast rise time of the impulse current. In this paper, a new frequency-dependent (FD) model of grounding systems (GSs) is presented that can be deployed in time-domain analysis. The proposed wideband modeling considers the frequency dependence of the soil electrical parameters (conductivity and relative permittivity). This model is sufficiently accurate for single-port and multi-port GSs buried in uniform and non-uniform soil in the frequency range of lightning. The main innovation of the proposed model is that it can be implemented in the time domain without requiring the inversion of the GS impedance matrix. Hence, this method is less complex than conventional approaches. As one of its applications, the effect of FD modeling of GS is investigated on the lightning overvoltages of a wind farm. The simulation results show that the frequency dependence of soil has a huge impact on overvoltage magnitude and the energy absorption of surge arresters (SAs) in wind farms; this effect varies according to the type of the GS and the soil resistivity, so it is of great importance from technical and economical points of view.

在雷击放电中，接地系统的瞬态行为受频率相关效应的影响。这些影响与脉冲电流的快速上升时间引起的复杂现象有关。在本文中，提出了一种新的接地系统 (GS) 频率相关 (FD) 模型，该模型可用于时域分析。提议的宽带建模考虑了土壤电参数（电导率和相对介电常数）的频率依赖性。对于在雷电频率范围内埋在均匀和非均匀土壤中的单端口和多端口 GS，该模型足够准确。所提出模型的主要创新在于它可以在时域中实现，而无需对 GS 阻抗矩阵进行求逆。因此，这种方法不如传统方法复杂。作为其应用之一，研究了 GS 的 FD 建模对风电场雷电过电压的影响。仿真结果表明，土壤的频率依赖性对风电场过电压幅度和避雷器（SA）的能量吸收有巨大影响；这种影响因 GS 的类型和土壤电阻率而异，因此从技术和经济的角度来看非常重要。