Coupon Monitoring for Cathodic Protection Optimization: Real-Time Automated Remote Control of Dynamic Stray Current on Pipe-Type Cables

Abstract Stray-currents represent a significant problem for integrity of pipe-type cables. Pipe-type cables (feeders) are generally outfitted with impressed current cathodic protection (CP) systems and have an external coating. Unfortunately, the coatings are imperfect in that there are holidays and disbonded sites, and the effectiveness of CP system in the presence of stray current is difficult to measure. An approach to assess the effectiveness of cathodic protection in dynamic stray current conditions, consisting of monitoring the IR-drop free polarization (Eoff) potentials of multiple Coupon Test Stations (CTSs), buried in close proximity to the monitored feeder has proven to be successful. The CTSs act as a backbone for the Coupon Monitoring For Cathodic Protection Optimization (CMCPO) system, which performs a real-time analysis of the instant Eoff potentials, and zero-resistance ammeter currents downloaded from the individual CTSs, categorizes the existing corrosion conditions along the monitored structure according to a customizable algorithm, and uploads the solutions to the remotely controlled CP rectifiers. This system provides the ability to remotely monitor and control CP of pipelines in stray current areas more accurately than ever before. The paper offers quantitative assessment of the CMCPO system performance and benefits.