Experimental model investigation of the corrosion of buried steel pipelines with cathodic protection near high voltage power lines

Abstract

The protection from corrosion of buried Pipelines used to transport gas and oil is always ensured by an insulation coating and secondly by a cathodic protection (CP), the latter reduces the corrosion and avoids eventual damage. But when pipelines are near a high voltage power lines, an alternating current (AC) is induced, thus causes the perturbation of the protection, and then serious damage by corrosion will take place. Our study aims to explain the basic mechanisms of corrosion (electrical and electrochemical) by the alternating current and how to minimize its impact on pipelines. Firstly, rigorous theoretical research showed us the main AC corrosion mechanism models and the standards illustrate zones of corrosion and immunity. Secondly, we conducted electrochemical tests on a laboratory sample (API 5L X52 pipeline). Thirdly, we did a simulation study in order to, digitally, represent the CP phenomenon, AC corrosion, and optimizing AC corrosion behavior by changing the CP in case of AC' interferences, by a monitoring program, which brings the process status to the immunity zone according to standards.