A Protective Measure against AC Induced Voltage on Pipeline by Means of Magnesium Anodes

Abstract

A systematic mitigation method has been developed for AC voltage induction of well coated pipelines due to proximity to overhead HVAC powerlines. The method is based on the use of magnesium anodes for cathodic protection. Magnesium anodes of about 5ohms were installed at 500 meters separation along a pipeline. Calculation of the voltage induced by fault current of a powerline indicate that the installation of 5ohms magnesium anodes at every 250 meters is suitable to suppress the maximum voltage below 5000volts. Field data of a pipeline having magnesium anodes at 250 meters separation show that this system is also satisfactory to mitigate the induced voltage under normal transmission of power.