Pulsed Current Cathodic Protection for Oil and Gas Pipelines: Current Status, Challenges, and Future Trends

Oil and gas pipelines are critical energy infrastructure, and their external corrosion protection affects public safety and economic operation. Pulsed current cathodic protection (PCCP) replaces continuous direct current with a periodically modulated output. This critical narrative review examines its mechanisms, operating parameters, applications, and engineering limitations. The evidence includes laboratory experiments, numerical models, and a limited number of field reports. Some studies report improved potential distribution or lower current demand, but these findings depend on the waveform, soil or electrolyte, coating condition, and comparison criterion. Double-layer charging contributes to the transient response; it does not independently establish sustained off-period protection, energy savings, or an increased protection distance. Pulse-related hydrogen evolution and coating damage also require separate assessment. Particular challenges include heterogeneous and frozen soils, stray-current interference, and interpretation of time-dependent protection potentials. Priorities are matched pulse–DC comparisons, independently validated models, synchronized monitoring, and long-term field measurements. The review identifies the evidence needed to evaluate PCCP for oil and gas pipelines without assuming that results from one installation are transferable to another.