Research On Energy Storage Technology Of Traction Substation In High Speed Railway

In the capacity design of traction transformer,the demand boundary is to meet the peak value of traction load.In the actual operation of traction power supply system,the duration of peak load is usually short,and the low capacity utilization of transformer is common.The research shows that the energy storage technology of traction substation can realize peak load reduction and valley filling,reduce the maximum demand,reduce the cost of electricity,improve the capacity utilization ratio of traction transformer,and be conducive to the economic operation of high-speed rail.The focus of this paper is to analyze the external characteristics of energy storage system in high-speed railway traction substation.Firstly,the advantages and disadvantages of various energy storage technologies and their development status are analyzed,and the type of energy storage suitable for high-speed railway traction substation is determined.Secondly,combined with the existing traction power supply mode,several topological design schemes of energy storage system in traction substation are given.On this basis,the charging and discharging strategies and charging and discharging characteristics of energy storage system in traction substation are analyzed theoretically.The influence of charging and discharging datum on charging and discharging depth,charging and discharging quantity and peak-shaving effect is investigated.Then the technical and economic analysis of traction energy storage system is carried out.The results show that traction energy storage technology has certain advantages in reducing maximum demand,saving electricity cost,absorbing regenerative braking energy,improving negative sequence and voltage unbalance,etc.The necessity of researching energy storage technology is verified.Secondly,an optimal allocation model with the highest economic efficiency or the lowest cost is established.With the capacity,power and SOC of the energy storage system as constraints,the optimal capacity of the energy storage device is 1040 kWh,the optimal power is 15 MW and the optimal charging and discharging threshold is 55 MW,respectively,and the charging and discharging thresholds and storage capacities under different energy storage power are given.The relationship between quantity and economic efficiency.Finally,the structure,working principle and control mode of bidirectional AC/DC converter and DC/DC converter are analyzed.Based on the platform of MATLAB/Simulink,the simulation model of energy storage system in traction substation is built to verify the effect of energy storage technology on peak and valley shaving.The influence of peak and valley shaving on traction transformer is analyzed.