Modeling And Simulation Of High Voltage Direct Current Power Systems Based On Voltage Source Converter

With the strategy promotion of 'western electricity to eastern',high-voltage direct current transmission occupies essential role in the electric power system in our country with its significant advantages.In rent years,the development of power electric technology has obtained breakthrough and progress,and high-voltage direct current transmission technology based on voltage source converter has become a new technology of high voltage direct current transmission.Compared with the traditional high voltage direct current,high voltage direct current transmission technology based on voltage source converterhas significant advantages.With the development of some technology,power system combined with power electric technology has a broad application prospect in the field of power systems.Especially wind power grid,power grid interconnection and other power engineering also can apply the VSC-HVDC system.In this paper,we set up mathematical model for high-voltage direct current electrical system which is based on voltage source inverter and carry out a series of simulation analysis by using the PSCAD.The main contents contain as follows:1.Stating the basic theory of VSC-HVDC,Analyzing the basic structure and working principle of VSC-HVDC based on voltage source inverter and laying theory foundation for further research on mathematical modeling and simulation analysis of VSC-HVDC based on voltage source inverter.2.Introducing simulation software PSCAD and its application.PSCAD is one of the simulation analysis software on power system widely used in the world,compared with other power system simulation software,and its advantage is that it provides users with complete graphical environment so that users establish circuit model and make relevant circuit simulation analysis.Mathematical model of VSC-HVDC power system parts is established,and main circuit and control circuit are modeled through analysis of overall structure of VSC-HVDC.Considering the influences of various factors,simulation foundation is laid by mathematical model which is as close as the real operation situation of VSC-HVDC power system.3.Taking Hellsjon engineering for examples,simulation analysis of VSC-HVDC power system is carried out,and parameters are studied for steady process and dynamic process.By analyzing and comparing the difference between actual system and simulation results,differences of regularity between actual system operation and simulation results are found and the foundation of VSC-HVDC power system optimization and perfectionis laid.