Capacity Configuration Method of Flexible Smart Traction Power Supply System Based on Double-Layer Optimization

The flexible smart traction power supply system (FSTPSS) is a new type of traction power supply system (TPSS) including converters, energy storage devices, and renewable energies. The capacities of the multiple components in FSTPSS have a significant impact on the economic operation and stable operation. And the capacity configuration optimization requires considering both the daily operating costs and long-term investment recycling, which has not been fully studied. Based on the characteristics of FSTPSS, this article proposes a double-layered capacity configuration optimization method by integrating the artificial fish swarm algorithm (AFSA) and CPLEX solver. The main goal of this method is to obtain the maximum economic benefits in the whole life cycle. Meanwhile, the operation time of FSTPSS when facing grid outage is also considered. The simulation results show that compared with the benchmark, the final converged maximum benefit value has increased by 43.6%, the grid power is averaged cut by 2.26%, and the sum of the daily cycle number of the energy storage devices increased by 27.3%. In addition, the proposed method can also improve the probability that the train can drive out of the current power supply interval in the event of a grid outage. By using the proposed method, this probability is increased by 9.27%.