Modelling AC Induction Along a Pipeline Aligned With an Overhead Power Line: Analysis, Simulations and Field Measurements

ABSTRACT The AC voltage is induced along a pipeline when an overhead power line is aligned with the pipeline. The AC induction needs to be analysed and determined even with cathodic protection systems (CPS) protecting pipelines, storage tanks, and many other metal surfaces in various industries to prevent electrochemical corrosion. Hence, the design and accurate operation of a CPS needs a proper model to monitor and assess the condition of pipelines aligned with overhead power lines. Conventional pipeline models, including lumped resistances introducing cables and connections, anode beds, and metal structures, do not represent the stated AC induction. This paper suggests a non‐uniform distributed model for pipelines aligned with overhead power lines driven by the CPS to determine the voltage profile across the long metal surfaces such as pipelines. The case study is an 11.5 km pipeline for gas transmission from a gas field located west of Iran, aligned with a three‐phase 20 kV overhead power line. First, the parameters of this gas pipeline model are analysed and obtained, which include resistances, non‐uniform inductances, and capacitances. Then, simulations are introduced for the developed distributed model. Finally, the voltage profile of the pipeline is obtained experimentally by measuring 23 points along the pipeline to confirm the model and simulations; also, waveforms of electrical potentials related to both ends and the midpoint are recorded by a portable oscilloscope for further verifications. Experimental results desirably validate the analytical distributed model and simulations.