An Energy-efficient Train Dispatch And Control Integrated Optimization Method In Urban Rail Transit Systems Considering Energy Storage

It is of great significance to study energy-efficient train operation methods,which can help reduce operating cost of urban rail transit systems,realize green and environment-friendly transportation and enhance competitiveness of the railway trans-portation industry.Thus,it has become a hot research topic in recent years.The main goal of energy-efficiency train operation is to reduce the amount of the net traction energy con-sumption,which is the electrical energy provided by substations for the traction of trains.It can be divided into two sub-goals,as reducing trains’ traction energy consumption de-mand("consume less")and improving regenerative energy utilization("utilize more").The two sub-goals are tightly coupled with each other through the same decision vari-ables(train driving strategies and timetable).Most of the existing optimization methods focus on only one sub-goal of the two,which limits their effectiveness and universality to some extent.In addition,the application of energy storage system makes it possible to utilize regenerative energy both in single train and multi-trains operation scenarios,and its energy saving effect deeply depends on the train driving strategies and timetable with a complex nonlinear relationship.Thus,it is a great challenge to study the energy-efficient train operation optimization methods considering energy storage systems.To achieve energy-efficient train operation in urban rail transit systems,this disser-tation studies the integrated optimization method on train dispatch and control consid-ering the configuration of wayside energy storage systems.The influences of wayside energy storage systems,train driving strategies and timetable on net traction energy con-sumption and their relationships are analyzed.A hierarchical model of train dispatch and control is proposed,and the optimization problems of driving strategies for a single train,inter-station running time reallocation and timetable redesign for multi-trains are studied sequentially,considering the configuration of wayside energy storage systems.A mathematical model of each optimization problem is formulated,and a heuristic algo-rithm is designed to solve it,respectively.Lastly,simulations based on the actual data of an urban rail transit system is conducted to prove the effectiveness of the proposed optimization methods.Taking the advantages of the combination of "consume less" and"utilize more",by applying the integrated optimization on timetable and train driving s-trategies in the context of wayside energy storage systems,the overall net traction energy consumption of an urban rail transit system is reduced to the greatest extent.To be specific,the main work of this dissertation are listed as follows:(1)A comprehensive combination of "consume less" and "utilize more" is proposed to reduce trains’ traction energy consumption,and an integrated optimization on train dispatch and control are studied,considering the configuration of wayside energy storage systems.According to the three layers of trains5 dispatch and control in an urban rail transit system,the optimization methods on driving strategies for a single train,inter-station running time reallocation,and energy-efficient timetable design for multi-trains are studied sequentially,to minimize the overall net traction energy consumption.(2)Energy-efficient train driving strategies are studied considering the configuration of wayside energy storage systems.Coast speed control is proposed to be the basis of train operation optimization in an inter-station.A mathematical model is formulated to simultaneously optimize a trains driving strategies in multi inter-stations within an ener-gy supply interval,and a two-step algorithm combining exhaustive search and improved artificial bee colony algorithm is designed to solve the problem.As both traction energy consumption demand is reduced and regenerative energy indirect utilization is improved,the net traction energy consumption of a single train is reduced effectively.(3)As running time in an inter-station impacts both a timetable and its correspond-ing energy-efficient driving strategy,an energy-efficient running time design problem is proposed in this chapter,considering wayside energy storage systems.An integrated opti-mization model is formulated,based on the driving strategy optimization model proposed in the last chapter.Running time in each inter-station is reallocated and its driving strat-egy is adopted correspondingly,thus more energy is saved for a single train operation scenario,with the constraint that total travel time maintains unchanged.(4)An energy conservation problem for multi-trains scenario is studied in an ur-ban rail transit system,considering wayside energy storage systems.A two-layer opti-mization model concerning multi-trains5 dispatch and control is proposed.A timetable optimization model is established,based on the optimization results for a single-train.Headway time and dwell time for each train are adjusted considering some realistic con-strains.The overall net energy consumption in an urban rail transit system in a whole day is minimized,by combining the energy-saving effect for each single train and taking full advantages of direct utilization of regenerative energy between traction and braking trains.(5)Simulations based on the real data obtained from a subway system in Beijing are conducted for all the optimization problems mentioned above.Experimental result-s prove the effectiveness of the energy-efficient optimization methods proposed in this dissertation.