An accurate investigation of lightning overvoltages on a typical mixed overhead-cable line is performed. The recently developed extended transmission line (TL) approach, frequency-dependent (FD) soil model and FD grounding system modeling method are also reviewed. The wave propagation characteristics of an overhead and a cable in frequency domain are studied using classical and extended TL approaches. Moreover, transient simulations using Numerical Laplace Transform (NLT) are carried out with different FD soil parameters and FD grounding behavior, and the influences of FD characteristics on the transient cable sheath voltages are made clear.

中文翻译：

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混合架空电缆中雷电过电压的准确分析

对典型的混合架空电缆上的雷电过电压进行了准确的调查。还回顾了最近开发的扩展传输线（TL）方法，频率相关（FD）土壤模型和FD接地系统建模方法。使用经典和扩展TL方法研究了架空电缆和电缆的频域传播特性。此外，在不同的FD土参数和FD接地行为的情况下，使用数值拉普拉斯变换（NLT）进行了瞬态仿真，并明确了FD特性对瞬态电缆护套电压的影响。