Study On Control Strategy Of Railway Static Power Conditioner Based On Energy Storage

Electrified railway has the characteristics of high safety coefficient,high comfort,large transportation capacity and less time consumption,which is an effective means to solve traffic inconvenience.But with the rapid development of Chinese electrified railway,power quality problems such as harmonic and negative sequence are also widely concerned.Meanwhile,more and more regenerative braking energy cannot be effectively utilized in traction power supply system.Now the traction substation is charged according to the two-part system electricity price,the problem that the regenerative braking energy cannot be effectively utilized will lead to a higher price charged for the two-part system electricity price and a greater economic impact.The investment of railway static power conditioner can effectively solve the problem of power quality,so how to solve the problem of power quality while utilizing the residual regenerative braking energy,reducing the peak load and improving the economy has become a research focus at home and abroad.Since the energy storage device has the characteristics of flexible charging and discharging,it can make full use of regenerative braking energy and reduce the peak load at the same time.Based on the above background,this paper studies the control strategy and parameter optimization of railway static power conditioner and energy storage system according to the data collected in a real substation.Firstly,the control strategy of traditional railway static power conditioner is studied.The simulation models of traction network,vehicle and railway static power conditioner are established according to the actual working conditions of railway vehicles,and the load characteristics of traction substation are simulated with this model.On the basis of the established model,the simulation calculation is carried out,and the effectiveness of the traditional railway static power conditioner control strategy is verified by comparing the results before and after the power quality control.Secondly,according to the field data collection and processing of a certain substation in China,the actual train operating load changes are obtained,and the maximum economic benefits in the life of the battery energy storage device are optimized.According to the judgment threshold of load peak reduction and the capacity of battery energy storage device,genetic algorithm was used to process the data of previous years to optimize the design.The typical operating conditions of several systems were analyzed,and the economic benefits of several energy storage systems participating in regenerative braking energy utilization and load peak processing are compared.Then,according to the real-time data of railway locomotive traction load,is presented based on the battery and super capacitor,battery and flywheel energy storage device coordination control strategy,through the new system of railway static power conditioner and energy storage device,the simulation model under actual working conditions is strategically verified,the results show that the control strategy can effectively recover the regenerative braking energy while improving the power quality,in addition,the peak load can be effectively reduced to the maximum extent when the peak load arrives,so that not only the power quality can be improved,but also the economic benefits can be further improved.Finally,based on the actual application situation,field investigation and energy storage system selection were carried out,energy management unit design was carried out,divide each working condition and sort out the energy management unit to receive and send the instruction signal.At the same time,balanced charge and discharge and frequent charge and discharge experiments of flywheel energy storage device were carried out.