Dynamic Simulation of Rail Potential and Stray Current Distribution Based on Fast Adaptive Boundary Element Algorithm

Currently, the impact of stray current is worsening. To control stray current and rail potential, over voltage protection device (OVPD), connection device (CD), and other equipment are widely used in metro. State transitions of the return system equipment cause dynamic changes in rail potentials, and together with changes in the surrounding heterogeneous soil structure, both directly affect the distribution of stray currents. Therefore, this paper proposes a method for calculating stray current and rail potential based on fast adaptive direct boundary element (FADBE), which takes into account the behavior process of reflux current equipment and surrounding geographical environment. FADBE not only greatly reduces iteration time, but also adaptively modifies parameters of reflux system. Through field experiments, the error in the calculation of FADBE is controlled within 6.87%. An authentic metro project is simulated and the results obtained from FADBE are found to be more consistent with the changes in rail potential and ground potential gradient observed. The results show that Different connections between the station and the main line can cause the surrounding ground potential gradient to vary by more than 43.47%. DC disturbances on metro lines near rivers and oceans should receive more attention.