A numerical model for the calculation of electromagnetic interference from power lines on nonparallel underground pipelines

This work proposes a numerical methodology for the calculation of currents and voltages induced on underground pipelines by nearby overhead power lines. A previously developed quasi-3D methodology is extended, allowing the investigation of nonparallel routings of the pipelines with respect to the power lines. The proposed technique is based on a discretization of the pipeline path into several segments parallel to the power line. The section of the corridor corresponding to each pipeline segment is regarded as an electrical multi-port component, whose electrical parameters are extracted via finite element 2D analysis. Then, the obtained components are integrated into a network embodying the physical characteristics of the whole corridor. In this way, the circuital analysis is used to extend the capabilities of a standard two-dimensional field analysis. The proposed methodology is employed to simulate a pipeline running parallel to a power line for a distance of 12km. Afterwards, several nonparallel configurations – consisting of crossings between a pipeline and a power line – are assessed. The physical consequences of the crossing are discussed and a convergence study is performed to investigate the optimal pipeline subdivision procedure to be adopted for a set of different crossing angles.