Research On Optimal Configuration Of Energy Storage And Recovery For Regenerative Braking On Long Steep Slope Of High-Speed Railway

In the complex and dangerous mountainous areas of Western China,due to the limited geographical conditions,the high-speed railway network traversing the mountainous areas often presents the characteristics of large design slope and long ramp line.High-speed railway train generates a large amount of regenerative braking energy when passing long and steep road sections downhill.If this energy is recycled and stored reasonably and effectively,it will be conducive to low-carbon transportation,energy saving and emission reduction,achieving the "3060 dual-carbon target",and more conducive to train safety.In recent years,with the vigorous development of new energy industry,the integration of photovoltaic resources into railway power supply and distribution system has become a research hotspot of green transportation.Due to the strong randomness of photovoltaic power generation,it is necessary to suppress fluctuations or allocate energy by configuring energy storage devices for traction energy consumption.In many forms of energy storage,the ground hybrid storage system has been widely studied because it does not increase the body weight and has the dual advantages of power-capacity.However,the economy of the energy storage media is still an important factor restricting its application.Therefore,it is very important to study the optimal configuration of ground hybrid energy storage system for efficient recovery of regenerative braking energy and efficient utilization of new energy resources in the road area to achieve energy saving,low-carbon operation of the railway system.This thesis takes the long and steep slope of high-speed railway as the research background,and takes the ground hybrid energy storage system as the research object.Based on the actual measurement data and aiming at efficient recycling of regenerative braking energy,the capacity optimization configuration of hybrid energy storage system is studied on the basis of analyzing the regenerative braking characteristics of high-speed train.On this basis,considering the connection to the photovoltaic power generation system,the hybrid energy storage system is intended to store both photovoltaic energy and regenerative braking energy to fully reduce traction energy consumption,and the optimal configuration of the hybrid energy storage system under the conditions of photovoltaic access is studied.Firstly,according to the measured data of regenerative braking energy return power for long and steep slope of high-speed railways,the power characteristics in different time dimensions and the energy characteristics of energy storage system operation are analyzed.Based on the characteristics of power stratification and energy stage,and combined with different performance indicators of each energy storage medium,a segmented configuration scheme for hybrid energy storage system is constructed.Considering the energy-time relationship,the calculation range of capacity allocation for hybrid storage system is determined,and an optimal capacity allocation model for hybrid storage system is established based on the global economic performance level.Secondly,an improved simulated annealing algorithm based on Levy flight function(LESA)is presented,which generates initial solution by Levy flight and keeps memory and update during the process of solving,aiming at the problems of high iteration times and low efficiency of traditional annealing algorithm.Taking a long steep slope road segment on the northern foot of Qinling Mountains,the capacity optimization model of hybrid storage system is solved by LESA algorithm.Finally,considering the photovoltaic access to traction power supply system,using Sketch Up software to build a 3D model,simulate the actual line environment,use the station subgrade to lay photovoltaic components,and then use Archelios PRO to simulate and analyze the photovoltaic output.Based on the analysis of the change of energy characteristics after photovoltaic access,the capacity allocation schemes of hybrid storage systems running independently and in parallel are given.An optimal capacity allocation model is built considering economy and comprehensive performance factors,and solved by LESA algorithm.The simulation results show that when the hybrid energy storage system only recycles regenerative braking energy,the system can recover 16.3% of the total traction power consumption.In the scenario of photovoltaic access,the annual operation recovery capacity of hybrid storage system reaches 31.7% of the traction power consumption.Energy recovery is of great value and great potential for energy reduction.The calculation results verify the superiority of LESA algorithm and the feasibility and validity of the optimal configuration method given.