Optimal Sizing of Supercapacitor-Based Energy Storage for DC Rail Transit Systems Using an Analytic Hierarchy Process Approach

Energy Storage Systems are widely recognised as highly effective solutions for enhancing the efficiency of electric Rail Transit Systems. Specifically, wayside solutions can significantly enhance network receptivity, thereby increasing the amount of Regenerative Braking Energy saved. However, determining the optimal size of storage devices is a complex task. To address this challenge, this study proposes a novel sizing procedure based on a multi-objective optimisation framework. This framework formulates the problem as a constrained linear least squares problem, with nonlinear constraints linearised. The effectiveness of this approach is then evaluated through numerical analyses focusing on a typical scenario involving a DC rail metro system.