Inductive interference on pipelines buried in multilayer soil due to magnetic fields from nearby faulted power lines

The interference of power transmission lines to buried pipelines, sharing the same rights of way, has been a research subject for many years. Especially under fault conditions, large currents and voltages are induced on the pipelines, posing a threat to operating personnel, equipment, and the integrity of the pipeline. The soil structure is an important parameter that affects the level of this interference. In this study, the influence of a soil structure composed of layers with different resistivities, both horizontally and vertically, on the inductive part of this interference is investigated. The method used to determine the inductive interference comprises finite-element calculations and standard circuit analysis. The results show that good knowledge of the soil structure is necessary in order to estimate the above interference with minimum error. Therefore, it is desirable that soil resistivity measurements are made both at adequate depths and at locations far away from the rights-of-way.