Calculation of protection current and anode selection using forced current method for buried oil supply pipelines

Underground oil supply pipelines are susceptible to electrochemical corrosion in complex soil environments. Accurate calculation of protective current and reasonable selection of anodes can ensure good protection of the pipeline and ensure safe operation. Clarify the current path, discretize the pipeline into micro element segments containing longitudinal and leakage resistance, and construct a basic model for calculating protective current. Based on this model, the actual polarization characteristics of the pipeline are obtained through power feeding experiments, and an objective function is established. A one-dimensional search method is used to achieve accurate calculation of protection current. Elaborate on the core requirements for anode selection, design a selection decision-making process to complete anode selection based on protection current requirements. The experimental results show that in the feeding test, the deviation between theoretical calculations and measured values is less than 15mV near the confluence point and less than 20mV at the far end, indicating the effectiveness of the design method. During the initial operation of the potentiostat, all 38 measuring points on the entire line met the -0.85V criterion for power-off potential and had no over protection. This method has practical application value.