Ac corrosion phenomenon and mitigation in buried pipeline due to very-high-voltage (VHV) overhead transmission line effect

Abstract

The presence of a very-high-voltage (VHV) electricity transmission line nearby a metallic pipeline can be a source of dangerous effects for this pipeline due to the electromagnetic field generated by this power line, it can induce a considerable voltage which may threaten the safety of operating personnel and the integrity of the pipeline. The main purpose of this paper is to evaluate the electromagnetic coupling effect in a buried metallic pipeline located in close proximity to a very-high-voltage (VHV) overhead transmission line using the Faraday's law and nodal network analysis under steady state conditions, as well as to estimate the possibility of AC induced corrosion of the metallic pipeline. The obtained results show that the induced voltage on the metallic pipeline exceeds the maximum threshold value recommended by the international regulations CENELEC and NACE, the AC corrosion current density surpasses the allowable value indicated by the specialized majority of corrosion studies. Therefore, a mitigation technique based on a pipeline grounding system is proposed to reduce the voltage induced on the pipeline to safe limits, in order to remedy the hazardous potential effects. The adopted mitigation technique has achieved better efficiency by reducing the induced voltage well below the safety limit.