Adaptive Cathodic Protection System Optimization for Submarine Pipelines under Multi-Source Stray Current Interference

The subsea crude oil pipeline faces severe corrosion challenges from multi-source stray current interference as it traverses areas densely populated with underwater power cables. This study addresses this complex operating condition by developing a numerical multi-physics coupled model integrating electromagnetic, electrochemical, and circuit theories to systematically unravel the synergistic mechanisms of alternating current (AC) and direct current (DC) stray current interference and their nonlinear impact on pipeline potential. The model is validated against published experimental data, demonstrating its reliability for predictive analysis. Our findings reveal that the coupling effect of multi-source interference can amplify pipeline potential fluctuations by over 38% compared to single-source interference, resulting in nearly half of the pipeline segments exceeding the safe potential window, thereby posing significant risks of localized corrosion and hydrogen-induced cracking. To mitigate these risks, we propose and design an innovative adaptive intelligent cathodic protection (CP) system based on Model Predictive Control (MPC) theory. This system utilizes a high-precision sensor network for real-time potential monitoring, leverages an embedded reduced-order model for predictive forecasting, and dynamically adjusts CP output to achieve active cancellation and precise compensation of dynamic stray currents. Simulation results, based on the validated model, demonstrate that this intelligent system elevates the pipeline potential compliance rate from 78.3% (conventional system) to 99.1%, enhances overall potential stability by a factor of 3.2, and reduces energy consumption by 22.5%. This research provides a comprehensive theoretical and simulation-based technical framework—from mechanistic understanding and risk assessment to active protection—for the integrity management of subsea pipelines in complex interference environments, holding significant theoretical value and engineering importance for safeguarding critical energy infrastructure. Future work will focus on field validation of the proposed system.