Energy-saving Optimization Method For High-speed Trains Considering Neutral Sections

As the main economy artery of comprehensive transportation,high-speed railway has the characteristics of safety,reliability,comfort and environment-friendly.It has effectively driven the rapid development of regional economic and industrial construction.It is the preferred transportation mode of the domestic public for mediumlong distance travel,and plays an irreplaceable role in China’s transportation system.With the increasing passenger demand,high-speed and high-density operation of trains will become the new normal of high-speed railway management.Under the background of the "double carbon" strategy,further shorten the train tracking interval to improve the transportation efficiency and further reduce the train operation energy consumption to improve the energy utilization of the railway industry are the focuses for the railway construction and operation management departments.Wayside neutral sections of traction power supply system are taken as the breakthrough point in this dissertation.Firstly,focusing on single train operation,in order to obtain the energy-efficient speed profile,the coupling relationship between neutral sections and speed limits are analyzed,based on the model of train auto-passing through neutral sections.On this basis,the trip time distribution strategy of train operation in multi-section is established.Further,for the adjacent trains tracking operation,the “time-space occupied band”(TSOB)model is constructed to optimize train interval.Finally,considering multi-train cooperation operation,the combined optimization problem considering neutral sections distribution is studied,to improve the online recycling of regenerative braking energy,The main work of this paper includes the following contents.(1)The train operation model with the typical scenario of passing through neutral section is established.Firstly,the key factors affecting the train tracking interval are analyzed.Based on the moving block interval control principle,the train moving authorization security envelope model is established.The key factors affecting the energy consumption of train operation are analyzed.Focusing on the energy flow of traction power supply system,a backtracking calculation model of train operation energy consumption considering the recovery and utilization of regenerative braking energy is established.On this basis,taking the train passing through neutral section as a typical operation scenario,the train operation model under three operating states of cruising,traction and braking is established to analyze the influence of train passing through neutral section on traction energy consumption and interval trip time.(2)An energy-efficient multi-phase speed profile optimization method for single train is proposed taking neutral sections into consideration.Focusing on the problem of discontinuous operation conditions caused by the coupling relationship between neutral sections and speed limits.Firstly,the model of train auto-passing through neutral section is established to analyze the influence of neutral section on trip time and energy consumption.Then,the section is divided into multiple phases,which are classified into five categories according to the coupling relationship.The multi-phase speed profile optimization model is established,with the vital speeds set of each phase as the decision variables.Finally,the PSO-SA hybrid algorithm is designed,which provides the basis for the subsequent single train sectional trip time allocation and multi-train collaborative optimization.(3)A trip time allocation method for multiple sections based on KKT condition is proposed in this paper.In view of the train energy consumption difference caused by the trip time redundancy in different intervals,the Pareto diagram reflect correlation between energy consumption and trip time for each section is obtained.Then,the second-order exponential function model is applied to described the analytical relationship between energy consumption and trip time.And the convex optimization standard model of trip time allocation with multiple constraints is established.By establishing the Lagrange function,the solution method based on KKT condition is designed,which solves the problem of Energy consumption optimization of multiinterval integral train traction caused by poor trip time allocation condition.(4)A train tracking optimization method with moving block based on model TSOB model is proposed.Firstly,TSOB model based on block time theory is established for both fixed block and moving block,and then the concept of block system resolution is adopted,and four quantitative analysis indexes for evaluating the occupation of track resources by trains are given.The TSOB model of a pair of trains’ tracking process is established,and the performance indexes of departure interval and total traction energy consumption in the train tracking process are optimized and analyzed in combination with the speed profile planning.It solves the problem that the train running block mode is not uniform in the interval and station,and it is difficult to realize the optimization of train tracking interval effectively.(5)A regenerative braking energy-efficient optimization method of multi-train cooperative considering neutral sections distribution is proposed.In view of the influence of the wayside neutral sections distribution on the recovery and utilization of regenerative braking energy under the multi-train cooperative operation,taking the operation of multiple trains on the upstream and downstream in peak hours as the research object,the wayside neutral sections distribution problem is incorporated into the multi-train cooperative optimization process,with the goal of maximizing the utilization of regenerative braking energy.A nonlinear programming model considering the optimization of tracking interval and wayside neutral sections distribution is established.The DLGA(double loop genetic algorithm)algorithm matching the proposed model is designed to obtain the optimal tracking interval and neutral sections distribution scheme,which effectively improves the utilization rate of regenerative braking energy.It solves the problem of high energy consumption cost in the later operation,caused by the relatively independence between railway construction and train operation management.This dissertation uses the actual rail corridor data,train data,field operation parameters,and combined simulation means,to verify the effectiveness of the proposed relevant models and algorithms.The relevant results can provide important theoretical reference for the small interval and low energy consumption operation of high-speed trains based on moving block high-speed railways in China.