Transient Electromagnetic Interference between Overhead and Underground Conductors

Electromagnetic interference (EMI) between overhead lines (OHL) and nearby pipelines may cause high-induced voltages. Their computation is important for the safe and reliable operation of the pipeline and necessitates the accurate evaluation of earth conduction effects on the impedance and admittance parameters of all conductors. In this article, a detailed formulation of the impedance and admittance parameters of OHL/pipeline configurations is presented and new expressions for the calculation of the mutual impedance and admittance between the overhead conductors and the buried pipeline are introduced. The mutual parameters for an OHL/pipeline configuration are evaluated by the new formulas and compared with those derived from existing ones, the method of moments and the finite element method. The propagation characteristics are also calculated justifying the use of the mutual admittance, that is typically disregarded in power systems EMI calculations. Transient simulation results with the developed formulas are performed to evaluate the importance of the proposed approach on EMI studies.