Simulation of Lightning Strikes on Towers Connected to the Grounding Grid and Located Near a Pipeline

Workers involved with underground pipelines might be subjected to dangerous transient voltages caused by adjacent lightning strikes on electrical towers linked to grounding systems. To better understand and predict these indirect effects, this paper investigates the transient electromagnetic behavior of a tower– grounding grid–pipeline system subjected to a direct lightning strike. The entire setup is simulated using transmission-line theory to enable a thorough understanding and accurate modelling of wave propagation, electromagnetic coupling, and ionisation across the various system components. A large-scale setup comprising five transmission towers linked by a grounding grid, and located near an underground pipeline with a total length of 2.8 km, is considered in this paper. The lightning current of 12. 5 kA is delivered at the first tower's top, and the pipeline transient currents and voltages induced are calculated. The lightning-wave propagation from the strike location through the tower arms, grounding grid, and soil to the pipeline is investigated under the assumption of uniform soil conditions. Different soil resistivities (100, 300, and 600 m) are used to assess their effects on system behaviour. Three electrical pipeline models, all based on transmission-line equivalences, are constructed and compared. The first model explores only resistive effects, whereas the second and third gradually incorporate inductive, capacitive, and conductive elements, thereby enabling a more precise depiction of electromagnetic coupling and dielectric losses. According to the simulations, the lightning current amplitude fades progressively through the resistive, inductive, and capacitive components of the tower, grounding grid, and pipeline. As expected, the induced current is maximum at the struck tower, and it decreases along the system. About the first pipeline model, the induced voltages were always at a level safe enough for personnel, regardless of the soil resistivity considered. However, the second and third models showed a significant increase in pipeline voltage, with the third model exhibiting very high voltages despite lower current magnitudes. Hence, the results clearly underscore the importance of pipeline modelling, soil resistivity, and electromagnetic coupling in evaluating lightning-induced hazards. The modelling approach introduced here not only advances understanding of the transient behaviour of grounding systems and pipelines subjected to lightning but also enables the development of safer grounding layouts, pipeline materials, and protective measures that better shield people from lightning hazards.