GIC effects on pipeline corrosion and corrosion control systems

The impact of telluric current activity on the corrosion control systems for pipelines in northern regions is examined. Three specific areas of concern are identified. These factors are corrosion of the pipe during positive cycles of the telluric disturbances, accurate measurement of cathodic protection performance parameters and coating damage during negative cycles of the telluric activity. Corrosion rates are calculated versus the magnitude of the pipe potential change caused by discharging telluric current for different values of the K-p geomagnetic index. Methods of compensating and mitigating telluric current effects are discussed in the context of the cathodic protection design and monitoring procedures. (C) 2002 Published by Elsevier Science Ltd.