Control of urban rail transit equipped with ground-based supercapacitor for energy saving and reduction of power peak demand

•Beijing line-5 metro supply network and trains were modeled. Real data of metro line and trains were obtained.•An algorithm was proposed to predict the maximum instantaneous regenerative energy of each station.•The maximum energy saving is around 21.8% at headway 270s and 18.6% at headway 360s.•The suggested ESS will save 1500MWh energy per year. The Daily energy saving is 12%. An energy storage system based on Supercapacitor (SC) for metro network regenerative braking energy is investigated. The control strategy according to the various power requirements in metro line and differing characteristics of these storage devices are proposed to manage the energy and optimize the power supply system performance. In order to estimate the required energy storage system (ESS), line 5 of Beijing metro network is modeled through a novel approach, in different running interval conditions based on the real data obtained from Beijing metro office. A useful method is proposed to predict the instantaneous regenerative energy which is delivered to each substation before applying ESS and based on that the ESS configuration for each substation is determined. A simplified mathematical model of the whole metro network has been developed and the main features of the control strategy have been developed. Numerical simulations show the efficacy of suggested control and the energy saving obtained for metro trains.