A Computational Approach for Assessing Coating Performance in Cathodically Protected Transmission Pipelines

The paper presents an efficient and accurate 3D computational approach for assessing the quality of the coating of sub-surface underground transmission metallic pipelines under cathodic protection control. The CP system consists of a series of Impressed Current anodic beds connected to the pipeline and distributed along its path. The computational approach addresses the problem of non-homogeneous electrolyte, by regarding the soil as a multi-layered film (of approximately 100m thickness) which is thin in comparison with the characteristic length of the pipeline of several kilometres, and contemplates different features of the conceptual model such as non-zero metal resistivity.

The aim of the simulation is to predict the status of the coating in contact with the electrolyte, and to estimate the size and location of coating defects given a minimal number of field potential measurements taken from surveys.