Research On Simulation Of Electrified Railways Centralized Access To The Grid With Wind Power

With the installed capacity of wind power and the scale of railway network continuously enlarging in China,the point of common coupling where electrified railway and wind power intensively access to grid has triggered a series of problems,among which the influence of electrified railway's power quality on the stable operation of wind turbine generators merits special attention.This thesis attempts to establish a simulation study on the interplay between high speed railway and electrical power system containing wind power by building a model on Matlab/Simulink.Its main contents are as follows:Firstly,it introduces the traction power supply system of high speed railway,including traction transformer,AT power supply model,the traction network of all-parallel AT power supply model as well as its modeling approach,then analyzes the load characteristics of the traction power supply system according to experimental data,and meanwhile elaborates the impact of harmonics and negative sequence aroused by electrified railway on wind turbine generators.Secondly,it introduces the traction drive system of high speed trains.AC traction drive technology shall be generally presented at first,and the two level four quadrant pulse rectifier follows.Then based on traction calculation and traction-braking characteristic curves of trains,it offers the calculation principle of equivalent current load in inverter DC link and a model of electrical system containing wind power.Finally,according to modulation mechanism of SPWM and definition of modulation degree,it provides the transient DC control strategies concerning carrier wave amplitude,and definitizes the calculation principle of modulation wave amplitude's proportionality coefficient.Thirdly,it establishes a model of the common connection where electrified railway and wind power intensively access to grid for a simulation study,consisting of traction power supply system based on NRF traction substation of LX high speed railway,a model of CRH5 high speed trains' equivalent current load in inverter DC link as well as a model of electrical system containing wind power.Finally,it proceeds a simulation study through the model aforementioned,by which the load characteristics of the traction power supply system are verified,the influence of electrified railway on electrical system containing wind power under the condition of different running speeds and regenerative braking mode is analyzed in detail,the interplay between electrified railway and electrical system containing wind power under different scales of wind power plants and different wind speeds is also elaborated,and the strategies of preventing these influences are also briefly discussed.