Research On Model And Simulation Of Continuous Traction Power Supply System

Single-phase frequency AC power supply system has been generally adopted in Chinese electrified railway,it has a variety of power quality problems dominated by negative sequence.Since the 13 th Five-Year Plan of China Railway,the train density and running speed has been increasing,and the problems of neutral section and power quality are becoming more and more prominent.Continuous traction power supply system is a new generation of traction power supply system that can eliminate the neutral section and solve the power quality problems at the same time,which is in line with the future development trend of the electrified railway.The simulation model of continuous traction power supply system can provide a design basis and theoretical support for new lines or power supply transformation lines.The topology of continuous traction power supply system is analyzed,the balance transformation principle of combined co-phase power supply system is given,its equivalent model is derived,and the calculation method of the main equipment capacity of combined cophase power supply is given.The mathematical models of parallel bilateral power supply system and tree bilateral power supply system are derived,the balanced current and the traction network impedance of different parallel connection methods are calculated.Simulation models under the two bilateral power supply schemes are built,and the validity of the theoretical derivation is verified.Based on the mathematical models of combined co-phase power supply system and bilateral power supply system constructed in this thesis,a simulation model of continuous traction power supply system based on the chain circuit model of whole line traction network is established.The power flow of continuous traction power supply system is solved by the continuous linear algorithm.The validity of the simulation model and algorithm is verified by Simulink.Taking an electrified railway continuous power supply transformation as an example,a simulation study on the power flow distribution and power supply capacity of continuous traction power supply system is carried out.The results show that the continuous traction power supply system has a more balanced load distribution on each traction substation,the utilization of regenerative braking energy is higher,the power supply capacity is stronger,the technical superiority can be demonstrated.In the meantime,the cross-zone power supply capacity of continuous power supply scheme is analyzed,the carrying capacity and the minimum voltage of traction network are verified.Finally,the expected main equipment capacity of combined co-phase power supply under the long-term traffic volume target is calculated,the power supply scheme is optimized within the national standard limits,the capacity of compensation device is reduced,and the construction investment is saved.