A quasi-3D approach for the assessment of induced AC interference on buried metallic pipelines

In this paper, a novel quasi-three dimensional technique for the study of electromagnetic interferences induced by overhead power lines on buried metallic pipelines located in the same corridor is proposed. The aim of the method is to provide an inherently three dimensional solution to the problem, by using a two dimensional finite element approach. According to the proposed methodology, a bidimensional quasi-magnetostatic analysis is performed on a section of the considered corridor. The three dimensional extension is obtained by using a circuital approach to consistently couple the analysed section with the rest of the system. The analysis of the obtained equivalent circuit finally provides the actual values of the longitudinal electric fields acting on the studied section, and thus allows the solution of the problem. The results obtained from the described procedure have been compared for a few simple interference cases with those obtained using Carson's analytical formulas for the calculation of mutual impedances. Finally, a study on the effects of a non-homogeneous soil structure has been carried out.