Diagnosis of the AC current densities effect on the cathodic protection performance of the steel X70 for a buried pipeline due to electromagnetic interference caused by HVPTL

Abstract

This paper diagnoses the effect of the AC current densities induced by the electromagnetic interferences between high voltage power line and buried power line on the cathodic protection performances of the X70 steel in the simulated soil. First, the induced voltage onto the pipeline was calculated for various power line configurations, separation distances between transmission line and pipeline and parallelism lengths. The induced AC current density was computed function to the induced voltage, soil resistivity, and holiday diameter. Then, the electrochemical characters of the X70 steel, at various AC current densities, are measured using the potentiodynamic method. The electrochemical parameters obtained by the electrochemical tests are used as boundary conditions in the cathodic protection simulation model. The results indicate that, under influence of AC current densities, the X70 steel is more susceptible to corrosion, and the cathodic protection is unable to maintain the protection potential.