Assessment of AC Corrosion Probability in Buried Pipelines with a FEM-Assisted Stochastic Approach

In this paper, a stochastic approach is combined with field theory and circuit methods to study how the geometrical and electrical properties of holidays (defects or pores in the insulating coating) in a metallic pipeline influence the probability of exceeding the current density limit for corrosion. Three-dimensional FEM simulations are conducted to assess the influence of the shape and electrical resistivity of the pore on the computed spread resistance value. The obtained results are then used to evaluate the probability of exceeding a given current density value for different sizes of pore and soil resistivities. Finally, a case of 50 Hz interference along a pipeline-transmission line routing is examined. The probabilistic approach presented in this paper allows the pipeline sections more subjected to the induced AC corrosion risk to be identified to be used as an auxiliary tool for adopting preventive protection countermeasures. Lastly, unlike most papers devoted to assessing electromagnetic interference on pipelines, the present work uses a probabilistic rather than a deterministic approach, representing its main novelty aspect.