Coordinated demand response of rail transit load and energy storage system considering driving comfort

Electric trains typically travel across the railway networks in an inter-provincial, inter-city and intra-city manner. The electric train generally serves as a load/source in tractive/brake mode, through which power networks and railway networks are closely coupled and mutually influenced. Based on the operational mode of rail trains and the characteristics of their load power, this paper proposes a coordinated optimal decisionmaking method of demand response for controllable load of rail trains and energy storage systems. First, a coordinated approach of dynamically adjusting the load of the controllable rail train in considering the driving comfort and energy storage battery is designed. Secondly, under the time conditions that satisfy the train's operational diagram, the functional relationship between the train speed and the load power is presented. Based on this, in considering the constraints of the train's arrival time, driving speed, motor power, and driving comfort, the capacity of energy storage batteries and other constraints, an optimization model for demand response in managing the traction power supply system under a two-part price and time-of-use (TOU) price is proposed. The objective is to minimize the energy consumption costs of rail transit trains, and optimize the speed trajectory of rail trains, the load power of traction system, and the output of energy storage batteries.