Research On New Reactive Power Compensation Scheme For Power Supply System Of Urban Rail Transit

Aiming at the problem of traditional reactive power compensation method for urban rail transit power supply system,such as high investment cost and construction cost,expensive labor and operation and maintenance cost,large floor space,low flexibility and poor compensation effect,A novel reactive power compensation scheme based on medium voltage energy feeders is proposed in this dissertation,which through dynamic compensation control strategy makes the power factor of the grid side to achieve the target value.At the same time,a reactive power optimization method based on particle swarm optimization(PSO)algorithm is proposed to optimize the reactive power instructions of VSC devices in each substation with the goal of minimizing the system loss,so as to achieve the purpose of reactive power compensation and reduce the system loss.The main work completed in this dissertation includes:(1)This dissertation studied the system composition of urban rail transit,and analyzed the generation and distribution of reactive power in the system;(2)The traditional reactive power compensation method for power supply system of urban rail transit is studied.The basic principle of reactive power compensation,calculation method of reactive power compensation value,advantages and disadvantages of traditional reactive power compensation methods are analyzed.(3)A novel reactive power compensation scheme based on medium voltage energy feed device is proposed.Firstly,the working principle and function of the medium voltage energy feed device are analyzed.Secondly,the basic principle,dynamic control strategy and over-modulation suppression of the new reactive power compensation method are analyzed and the corresponding calculation method is given.Meanwhile,a reactive power optimization algorithm based on PSO algorithm is proposed,including the basic principle,parameter setting,mathematical model and solution process of PSO algorithm.(4)The new reactive power compensation method is verified by simulation and algorithm.Firstly,the reactive power characteristics of the system are analyzed.Secondly,the dynamic compensation strategy is simulated,the simulation results show that the proposed control strategy has fast response speed and good control effect;Meanwhile,the reactive power optimization algorithm based on PSO is verified,and the results show that PSO algorithm has good optimization effect,can achieve the goal of minimum power loss of the system,and has better convergence speed and optimization results than genetic algorithm(GA);At the same times,the good performance of the new compensation scheme is verified by the comparison between the new compensation results and the centralized compensation results.Figures: 33,Tables: 6,References: 72.