Optimization of Train Grounding System in Dual Traction Power Supply System

In a dual-traction power supply system (DTPSS), an improper value of onboard grounding resistance could result in a larger current distribution, axle end potential, and surge overvoltage (SOV) of the vehicle body (VB) because of the interaction between the ac and dc traction power supply system and the train crossing the neutral sections. Therefore, it is important to carefully select the appropriate value of the resistance and position of the grounding points. This research article proposed the steady-state model of DTPSS to evaluate the current distribution and axle-end potential, and the transient state model of DTPSS to calculate the SOV of the VB of vehicle grounding systems (VGSs). To obtain the best optimal solution, particle swarm optimization (PSO) and the technique for order of preference by similarity to ideal solution (TOPSIS) multiobjective optimization techniques have been implemented. The accuracy and efficiency of the VB current distribution are verified by observing the experimental and simulation results. The proposed VGS optimization technique demonstrates that the VB current distribution has achieved a significant improvement of 24.8% of the total current in the dc section and 21.1% of the total current in the ac section. By observing experimental, simulation, and optimal solutions of transient models in DTPSS, the SOV value was reduced to 33.4% of the total voltage.