Modeling and Analysis of Traction Power Supply System of Urban Rail Transit

Since the 18th National Congress of the Communist Party of China, China's economy has developed rapidly, the process of urbanization has been accelerating, and urban traffic congestion has become increasingly serious. Therefore, many cities began to focus on the construction of modern rail transit. This paper first analyzes the components of the AC/DC traction power supply system, and focuses on its modeling and simulation. AC power supply mainly includes external power supply, main substation and medium voltage power supply network. In the process of modeling the main transformer, the calculation formulas of the parameters needed in the Simulink model of the main transformer are derived theoretically. The method of reactive current detection is studied, the SVG model of double closed-loop control is established, and its compensation function of reactive current is verified. For the rectifier unit which is the core equipment of DC traction substation, this paper mainly discusses the rectifier principle of 24 pulse rectifier unit, which is widely used now. On this basis, the parameter calculation formula of split winding transformer in rectifier unit is derived. The model has been verified and its correctness is guaranteed. This paper also builds the traction network model according to the equivalent circuit. According to the actual structure of AC/DC traction power supply system of general urban rail transit, A Simulink model of AC/DC combined power supply system is built and simulated to detect its accuracy and point out the existing problems.