MODELING OF THE PROTECTION CURRENT/POTENTIAL DISTRIBUTION IN CATHODIC PROTECTION SYSTEMS WITH A GALVANIC ANODE BY USING THE COUPLED BEM/FEM METHOD

Abstract

The use of numerical methods for calculation of protection current/potential distribution in cathodic protection systems with galvanic anodes is presented in this paper. The coupled BEM/FEM method has been analysed, i.e. a combination of the Boundary Element Method (BEM) and the Finite Element Method (FEM). The cathodic protection system is a very efficient system for the protection of underground metal structures from corrosion. The most important phase of the projecting of the cathodic protection system is the optimally and technically correct defining of protection current distribution.. The calculation of protection current/potential distribution in cathodic protection systems is based on solving Laplace’s equation using adequate, previously defined, boundary conditions. These conditions are defined by using analytical expressions for the functional relationship between protection current and potential on electrode surfaces, or the electrode/electrolyte boundary. On the same structure for which the numerical calculations were made, measurements of protection potential distribution during the time of exploitation have been taken. Experimental data acquired during the start of system operations, together with intentional periodical measurements during system maintenance, are compared with data acquired by numerical calculations.