An Integrated Train-earth-pipe Stray Current Diffusion Model in DC traction power supply system

The dynamic stray currents generated by subways can lead to corrosion and damage in buried metal pipelines. This study investigates the diffusion characteristics of stray currents by considering the control mechanisms and operational behavior of power supply system devices within complex spatial and conductor structures. A unified fieldcircuit coupling modeling approach is adopted to integrate the direct current (DC) traction power supply system model, stray current field model, and pipeline system model. This approach is applied to a specific case study, with the calculated results compared against COMSOL simulation outcomes. For a 15.3 km pipeline, the average deviation in pipe-to-earth potential is found to be 6.10%. Moreover, the accuracy and reliability of the proposed method are verified through a 24-hour field test of pipe-to-earth potential. Finally, based on the case analysis, the study introduces several evaluation indices for assessing stray current interference in pipelines.