Modeling of the KOH-Polarization cells for mitigating the induced AC voltage in the metallic pipelines.

The problem of AC corrosion remains motivating for researchers because many factors influence the corrosion rate for buried pipelines due to the interference with overhead high voltage transmission lines (OHVTLs). Many researchers study the mechanisms of induced alternating current (AC) voltages, which are summarized as capacitive, inductive, and conductive coupling. In this work, only the induced AC voltage on the pipelines due to inductive coupling in steady-state conditions is studied. A holistic mathematical model for the pipelines, power lines, mitigation equipment for the induced voltage, and cathodic protection (CP) is illustrated. Potassium hydroxide polarization cells are electrically represented because these cells are considered the most common mitigation device for discharging the induced AC voltage from the pipeline to the soil. The overall model is implemented using MATLAB. The results show the profiles of induced AC voltage along the pipeline, the CP for the pipeline, the points of maximum voltage, and the influence of installing the AC mitigation units on the CP performance.