Optimal stationary super-capacitor energy storage system in a metro line

In this paper, the feasibility of using stationary super-capacitors to store the metro network regenerative braking energy is investigated. In order to estimate the required energy storage system (ESS), a very simple model for metro network is developed. Using the model of metro network for a particular station, a new approach is proposed to find an appropriate cost function for sizing the ESS components. By minimizing the proposed cost function, the optimum rating of components and appropriate control strategy for dc-dc converter can be realized. A case study is provided and simulated for station five of line three of Tehran metro network using Matlab software optimization toolbox.