Optimal design of onboard super-capacitor based energy storage systems for urban electrical rail transportation using Particle Swarm Optimization

Train braking energy regeneration in electrical rail transportation systems can reduce the energy consumption and operational cost of the system. In this paper, optimal design of an onboard energy storage system (OESS) for urban electrical rail transportation systems (ERTS) is presented. Super-capacitors are considered as the storage system. Determining the optimum capacity of the energy storage systems minimizes the total cost of energy storage installation and energy cost while improves the voltage profile of the system.Particle Swarm optimization (PSO) is used for the optimization the storage system capacity. The objective function is a summation of the energy consumption and super-capacitor depreciation costs. Optimization is executed considering five different traffic scenarios for daily metro headway and passenger. Super- capacitor charging and discharging control program is set based on the train voltage. A part of Line 1 of Tehran metro is used for the case study. Simulation results confirm the effectiveness of the proposed optimization method.

Keywords:

electrical rail transportation system (ERTS) , onboard energy storage system (OESS) , super-capacitor , Particle Swarm Optimization (PSO)