Research On Harmonic And Negative Sequence Compensation Of Electrified Railway Traction Power System Based On STATCOM

With the implementation of medium and long-term railway planning,the influence of electric railway traction power supply system on the power grid is increasing.Because the electric locomotive has nonlinearity and volatility,it injects a large number of harmonics and negative sequences into the power grid during operation,which will cause the three-phase asymmetry of the power grid and seriously threaten the safe and stable operation of the public power grid.Therefore,effective compensation measures must be taken to improve the reliability of power supply for the public power grid and ensure the safe and stable operation of the traction power supply system.This thesis describes in detail the electric traction power supply system,including traction transformers,electric locomotives and other important components,through the PSCAD simulation software,build five kinds of traction transformers and three kinds of locomotive simulation model.At the same time,the mathematical models of current unbalance of five traction transformers are deduced,and three-dimensional simulation modeling is performed.The inhibitory effect of different traction transformers on negative sequence is analyzed.Subsequently,the three types of locomotives are respectively added to the traction power supply system symmetrically distributed to the power supply arm,and the FFT module is used to detect the voltage and current distortions,and the influence of the traction power supply system on the power grid is analyzed.Combining with the actual situation,from the locomotive number,model,and working conditions,multi-scenario simulation analysis is performed,and a large amount of simulation data is available.In many scenarios,the harmonics and negative sequence at the public connection point are more serious.In order to solve the harmonic and negative sequence problems in the traction power supply system of electric railways,this thesis applies the static synchronous compensator(STATCOM)for flexible AC transmission to electrified railways,and simulates and analyzes the symmetrical distribution and multiple scenarios of a single locomotive.The simulation results verify that the static synchronous compensator...