Inductive coupling on metallic pipelines: Effects of a nonuniform soil resistivity along a pipeline-power line corridor

Metallic buried pipelines sharing the same corridor with AC power lines are subjected to AC interference, potentially harmful to personnel and equipment. The inductive coupling depends, among other factors, on the physical characteristics of the soil. This work presents an analysis of the effects of soil resistivity nonuniformities spanning along the length of a corridor. The investigation is performed by assessing several realistic configurations suited to highlight the various mechanisms affecting the phenomenon. The calculations are carried out employing an ad-hoc developed numerical tool, where the network analysis is used to enforce physical constraints on a 2D finite element analysis. The obtained results show that longitudinal nonuniformities in the soil resistivity can significantly affect the induced currents, depending on the particular configuration of the power line under exam.