Analysis of Indirect Lightning Coupling to Overhead Lines Above Multilayer Dispersive Soils with Uncertain Water Percentage

This paper presents a method for quantifying the coupling values induced by indirect lightning on overhead lines above multilayer soil with uncertain water percentage. The method employs the Nakagawa multilayer earth-return impedance model, extending the solution approach from field-to-wire coupling model on single layer dispersive soil to multilayer soil. To address the uncertainty of coupling values, the generalized polynomial chaos expansion method is employed, while the stochastic response surface method is utilized to compute the expansion coefficients. These coefficients are pivotal in determining the statistical characteristics of the coupling values. Finally, the effectiveness and efficiency of the proposed method are validated through Monte Carlo simulations.