Lightning-Induced Transients in Buried Power Cables: A Study of Soil Dissipation Effects

When a cloud-to-ground lightning strike occurs, the majority of the lightning current dissipates into the surrounding soil through grounding networks. However, limited work has been conducted on how this soil dissipation affects the transient response of buried power cables. This article investigates the impact of current soil dissipation via two different paths, one with extended soil dissipation and one without, by injecting impulse currents into a metal testing platform. The results show that, with an extended soil dissipation path, even involving much steeper impulse current, the core-to-ground voltage of a buried cable is reduced by approximately 50% compared to the condition without extended soil dissipation. Additionally, the current in the armor layer increases nearly fourfold. The shielding effectiveness (SE) for the armor layer, grounded at both ends, improves from 5.18 to 7.56  dB. As the impulse current amplitude increases, the effect of extended soil dissipation on the transient response of the buried cable becomes more pronounced. Specifically, both the core-to-ground voltage and the armor layer current exhibit nonlinear growth, while the SE values continue to improve with increasing current amplitudes. Finally, the article provides some engineering recommendations based on these findings.