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Project: T153700 #3420
 

High-pressure fluid-filled (HPFF) cables are the most widely used pipe-type electrical transmission line, accounting for 80% of all underground transmission lines [1-4]. Corrosion is a primarily concern for pipe-type cable systems, specifically regarding the cable pipe. Steel pipelines can corrode if they come into contact with water and salts in the soil. If the surface of the pipeline is damaged, corrosion is likely to occur, resulting in the leak of the fluid contained between the pipeline and the electrical conductors. Insulating coatings used on the outside of the cable pipe are the most common procedure for protecting a metallic pipeline from corrosion. However, these coatings cannot be made perfectly due to small imperfections that can develop during application, handling, transportation, installation, high operating temperatures, or by external agents such as chemicals in the ground. In addition, external parts adjacent to the pipeline such as valves and casings, are more prone to corrosion than the other part of the pipe. Coating delamination or blistering produced by environmental conditions can be exacerbated by inadequate cathodic protection design; therefore, the correct application and monitoring of these coatings under working conditions is mandatory for a reliable pipeline system. As of today, there is no commercial technology that monitors the state of the coating during service conditions. In this investigation, we characterize the state of the coating in different pipeline samples by following two different standards; the first includes high temperature electrolytes and the second, salt spray in cycling environments. Both methods can reveal the coating performance during aggressive accelerating conditions.

Keywords:

Accelerating testing, Coatings, Delamination, Surface characterization