Influenced Voltages on Pipelines by Overhead Lines Operated at AC, DC and with Lightning Conditions

The Pipelines for oil or gas are often build for many kilometers in parallel to high voltage overhead lines. Modern ones are well isolated by polyethylene coating for corrosion protection reason. Especially if short-circuit or lightning currents are present on the overhead lines the influenced voltage on the pipelines can reach very high magnitudes. To prevent deadly over voltages pipelines are earthed every few kilometer. As this grounding is often performed by 90 m deep drillings or huge flat earth electrodes to be less than 2 Ω, it can be rather costly. In this paper, a self-developed software is used to calculated pipeline over voltages and to optimize the number of earthing points. As nowadays AC overhead lines get sometimes upgrade to DC applications for capacity reasons expectable changes in influenced pipeline voltages are simulated and discussed for short-circuit and lightning conditions.