Fast evaluation of lightning-induced voltages of overhead line and buried cable considering the lossy ground

Abstract

In this study, an efficient method for the evaluation of lightning-induced voltages on a single-conductor overhead line and a single-core buried cable is proposed. In this method, the numerical evaluation of the temporal convolution due to the lossy ground is simplified by a full consideration of the inherent relation between the frequency-dependent ground impedance perunit- length (p.u.l.) and admittance p.u.l., based on which, the evaluation of the lightning-induced voltages on an overhead line or buried cable system can be implemented in an efficient way. To further improve the efficiency, the frequency-domain method of evaluation of the lightning horizontal electric fields above or below the ground surface is modified by dividing the lightning channel base current into high-frequency and low-frequency components. Some numerical examples are conducted under MATLAB platform to validate the proposed method and the efficiency is discussed.