The Application Analysis And Simulation Research Of Voltage Source Converter Based High Voltage Direct Current Technology In Railway Power Supply System

The 10 kV AC power system of the railway is mainly used for railway power supply,providing power protection for dispatching command,communication signals,and passenger services.Due to the vast land area of our country,the environmental differences along the 10 kV railway are more obvious.It is located in the power supply line in the sparsely populated areas of the Qinghai-Tibet Plateau or the desert.When the external power supply is scarce,it has to adopt ultra-long distance transmission,which increases the terminal voltage of the line.The quality of power supply deteriorated.Voltage source converter based high voltage direct current is a new type of HVDC transmission,which has many advantages over traditional AC transmission.In order to meet the demand of high-speed railway operation and further improve the quality of power supply,this paper studies the basic principle and structure of the flexible DC transmission technology used in 10 kV railway power supply system based on the characteristics of railway power supply system,and obtains the mathematical model of the system through theoretical calculation.The different control strategies for connecting AC networks at both ends of the system are analyzed,and the design methods of the controller are given.Using PSCAD software,the simulation model of the system is established,the output results are analyzed,the effectiveness of the control strategy of the system and the correctness of the mathematical model established are verified,and the theoretical basis for the application of flexible DC transmission in the future railway power supply system is laid down.