Vertical Optimization Of Urban Rail Line For Energy Saving

With the rapid development of urban rail transit in China,Metro track millage has been sustainable increased.The consumption of electrical energy,which is the major power for operating subway has also been continually increasing annually.Among all the ingredients that could impact the energy consumption,train traction accounts for a half of its total energy consumption within the whole metro system.Therefore,reduce the energy consumption in train traction becomes a significant point to control the power consumption of the urban rail transportation system.Vertical alignment of urban rail transit lines would exert an effect on the scale of additional resistance for gradient in the operating process and thus influence the locomotives' operation curve and traction energy consumption at the same time.Therefore,various methods to optimize the vertical alignment line design which can contribute to reduce the traction consumption of locomotives has a high research valueThe subject of this research paper will primarily focus on underground lines of urban rail transit which were built by adopting shield-tunneling method.The first part includes a summary and debrief about the knowledge related to vertical alignment design of urban transit lines.Additionally,exploit the computational software of locomotive traction simulation(model)to highlight the overall locomotive performance under different designs and generalize the general principle of energy-saving gradient Based on the two foundational steps,build an energy-conservation optimized model for vertical alignment design of urban transit lines and develop "Genetic Algorithm" to solve problems.In addition,taking advantage of the "MATLAB GUI platform" in the secondary development of being designed model and algorithm.Moreover,establish an energy-saving vertical alignment design for the urban mass transit.The main contents of this research include the following aspects:(1)Through doing research about the Codes for Metro Design and some practical designed examples to summarize the five significant factors of vertical alignment design,including goals,contents,requirements,procedures,and influences.Exploit the computational software of locomotive traction simulation(model)to devise the constant altitude platform that keeps the first and the last stop equal.In addition,take the three stops which station spacing features with 1000M,1500M,2000M accordingly as a typical case and exploit the computational software of locomotive traction simulation to imitate the techn-economic indexes of locomotives that runs through the mentioned above stops under different vertical alignment design.Based on the data and model to do an empirical analysis of general principles of designing an energy-saving slope.Simulation results shows that the form of V-groove design fits all the stations which station spacing is shorter only when the exit and entrance of the locomotive characterized with "steep downgrade,gentle downgrade" and "gentle upgrade,steep upgrade" correspondingly.Also,the length of grade section should be appropriately kept range from 200 to 300 meters and the gradient of grades should be kept range from 8‰?14‰ to match with it.However,for the stations which station spacing is longer,the W-shape grade featured with "steep downgrade,gentle downgrade,gentle upgrade,gentle downgrade fits better.Its energy efficient will be optimized especially when length of grade ranges from 200 to 300 meters and the gradient of grade range from 18‰?26‰.(2)Specific to rely on shield tunneling method to construct the urban transit network,this article proposes an optimize goal that minimizing the locomotive's total traction energy consumption that operating on both sides of the metro tunnels by adopting time-saving mode.In addition,develop a unique optimized and energy-saving vertical alignment model that views the length and gradient of the grade section as decision variables.This model takes both grade length,gradient,location of vertical curve and related design criterion into account.It also presents the practical requirements which can be seen as constraint condition,for instance deep-buried lines,avoid elevating area.In order to improve computational efficiency,make an adjustment to the scope of constraints which could influence grade gradient and length through referencing with general principles of energy-saving grade design.Moreover,create the correspondingly "Genetic Algorithm" to serve this model.The outcome of this case indicates that compared with the original track profile design scheme,by adoption of the new design--stemming from the model that stated in this article,the energy saving effect could reach 3%?12%.(3)In order to expand the overall applicability and simplify the operability of the optimal track profile model and solution algorithm that designed in this article,the existed METALAB PLATFORM was exploited to optimize the performance of both the new model and algorithm,meanwhile,establishing a new energy-saving track profile system of urban transit.In addition,the system was divided into three basic parts,including basic data module,track profile assessment module,and track profile design module.It could evaluate locomotives' energy consumption and operational time span under specific design scheme.One of the significant functions is that automatically forming a vertical alignment design between different lines on the premise of givenoriginal-destination and relevant constraints.In addition,this system can assist the engineers with designing vertical alignment on the basis of giving a specific plane lines design.