Detailed versus simplified representation of a pipeline for assessment of inductive and conductive couplings to an overhead transmission lines during steady-state and fault conditions

Abstract

Electric power systems influences on nearby structures have been widely investigated in the last decades. Generally, the practical projects contemplate simplified studies that calculate just part of the system. The literature is vague regarding whether this standard procedure may cause a difference in the calculated results. This paper investigates inductive and conductive influences along a buried pipeline from an overhead transmission line during normal load operation and fault conditions. Two situations are compared: only part of the pipeline stretch near the interfering system and its total length. A case study investigates the influences from an overhead transmission line on a buried pipeline for parallelism and crossing approaches by proposing an accessible methodology, whose results are compared with commercial programs widely used by design engineers and with good accuracy. The main focus of this work is to show that the most common practice of considering only the region where an overhead line is closest to the pipeline may lead to underestimating the induced voltage. Instead, to correctly assess pipeline-induced voltage, one may need to represent in detail the whole pipeline. High deviations indicate that a pipeline may suffer corrosion and put personal safety at risk if mitigation measures are not implemented. Computations considering the whole pipeline path are essential for structural and personal integrity. Besides, the proposed accessible methodology is useful, given alternatives to the few commercially available software.