Identification of Coating Defects in Cathodically Protected Underground Pipelines

Abstract

Coating defects may occur, for many different reasons, at some points on the surface of a cathodically protected structure. These defects behave as anodic and may cause strong localised corrosion. It is possible to identify the position of coating defects by using measured values of the electrochemical potential at some points in the electrolyte or on its surface. To achieve this, an inverse BEM-based genetic algorithm is developed to identify the position of defects in cathodically protected underground pipelines. The formulation is validated through its application to practical problems involving strongly non-linear polarisation curves, infinite electrolytes, unknown number of defects and measurement noise.