Simulation Modeling Of DC Traction Power Supply System Of Urban Rail Transit And Development Of Simulation Platform

As the vanguard of "new infrastructure",urban rail transit is the artery to support the efficient operation of the city,and also an important indicator of the development level of the city.The traction power supply system of urban rail transit is an important part of urban rail transit system,and the key to sustainable development is to save energy and reduce emissions and improve intelligence.This thesis replaces the traditional diode rectifier traction substation with energy-fed traction substation,establishes the electrical steady-state model of energy-fed traction power supply system,and develops a graphical simulation platform for urban rail transit traction power supply system.Firstly,the composition of the DC traction power supply system is introduced then the traction network,diode rectifying unit,PWM rectifying unit and train are modeled,at the end,the energy feed traction power supply system model is established.In the modeling and simulation technology of DC traction power supply system for urban rail transit,three parts are studied,including traction calculation,tidal current calculation and return current distribution calculation.For the traction calculation,this thesis designs a train traction algorithm under the constant acceleration traction strategy by studying the train mechanics theory,operating conditions and traction strategy,and obtains the information of speed,acceleration,power and traction force during the train operation;on the basis of the train traction calculation,the DC tidal current calculation is carried out with the train node as the power source,and based on the DC output characteristics of PWM rectifier unit,a Based on the DC output characteristics of the PWM rectifier,the Newton-Raphson algorithm based on voltage sag control is proposed;for the return current distribution calculation,the "earth-trail" return current system structure model is established under the bilateral power supply mode,and the current and voltage of the train and traction substation obtained from the DC current calculation are used as the boundary conditions for the return current parameter distribution calculation.The calculation expression of return current distribution is derived,and the algorithm of return current parameter distribution under bilateral power supply is designed to calculate the stray current and rail potential of the return current system.In order to improve the intelligence of urban rail transit system,this thesis develops a graphical urban rail transit traction power supply system simulation platform based on Visual Studio 2013 using C# language.The platform can build a simulation line in the drawing area according to the line condition,set relevant electrical parameters,perform traction calculation,current calculation and return current distribution calculation,and provide data support for the design and adjustment of its power supply system.Finally,the DC traction power supply system simulation platform for urban rail transit is verified with an actual line as the background,and the results show that the simulation platform can realize the graphical simulation construction of the line.The results of traction calculation,DC current calculation and return current parameter distribution calculation are in line with the actual engineering situation.Figures: 54,Tables: 8,References: 58.