Modeling for VSC-HVDC electromechanical transient based on dynamic phasor method

VSC-HVDC is a DC transmission system based on voltage source converter , in which the whole switches are full controlled. The new generation of HVDC transmission technology (VSC-HVDC) are based on VSC consisting of full-controlled devices and Pulse Width Modulation (PWM) technology. VSC-HVDC electromechanical transient model can meet the need of the simulation on large power grid, because electromagnetic transient model is not suitable for large power grid. Conventional electromechanical transient model is a phasor model based on "steady state" or "quasisteady state" assumption. With lots of FACTS devices widely used in power system, “continued rapid dynamic changes “occur in it. In this case, conventional electromechanical transient model is not accurate. Dynamic phasor method is not limited to these assumption, which is more accurate to analyze "continued rapid dynamic changes" in power system. There is rarely suitable electromechanical transient model for VSC-HVDC so far. So there are lots of work to do with modeling for VSC-HVDC electromechanical transient. This paper describes the dynamic phasor theory, and establish the VSC-HVDC model based on dynamic phasor method, then simulate with this model in MATLAB to verify the correctness and compare with the existing models.