Energy Transfer Strategy for Urban Rail Transit Battery Energy Storage System to Reduce Peak Power of Traction Substation

In order to reduce the peak power of traction substation as much as possible and make better use of the configu-ration capacity of battery energy storage system (BESS) in urban rail transit, a BESS control strategy based on energy transfer is proposed. Based on the actual subway line data, the load characteristics of urban rail transit with different departure intervals are analyzed by using the simulation platform of urban rail transit traction power supply system. Then, based on the characteristics of urban rail traffic load and the high energy density of the battery, the SOC dynamic adjustment module and discharge threshold dynamic adjustment module were added. The discharge threshold is dynamically adjusted according to the SOC of the battery, and part of regenerative braking energy absorbed by the energy storage device is transferred from off-peak/flat peak period to peak period for release. The simulation model and 90 kW physical platform are used to verify the proposed control strategy, and the results show that the control strategy can effectively realize energy transfer. Not only can achieve energy saving and voltage stability, but also can effectively reduce the peak power of traction substation, bring more economic benefits.