Three-Stage Energy Management of Urban Rail Transit-Based Microgrid and EV Charging Station With V2T Technology

Abstract

To achieve the efficient energy dispatch for urban rail transit-based microgrid (URT-MG), including energy storage system (ESS) and renewable energy source (RES) with electric vehicle charging station (EVCS) via vehicle-to-traction (V2T) technology, this research proposes a three-stage energy management with different time scales. In the first stage, based on a novel energy structure of URT-MG with EVCS, a coordinated control strategy of the integrated system is achieved, which can reduce the substation peak power. Then, the minimal operation cost of urban rail transit (URT) substation is obtained by a day-ahead energy management considering the forecast data of RES and different discharging capacities of EVCS. As for the second stage, the deviation between actual operation and referral dispatch plan from the first stage is eliminated by the model predictive control (MPC) method considering the uncertainties. In the third stage, an adaptive charging strategy of individual electric vehicles (EVs) is designed. This strategy can dynamically adjust the charging power of each EV to meet the travel demand of EV customers. The simulation based on the Merseyrail line of Liverpool is conducted, which verifies the validity of the proposed strategy. The substation energy cost can be reduced by 51.0%, while the EVCS charging cost is also reduced by 46.0%.