The Research Of Load Flow Automatically Soft Flip And Characteristics Of Regulation Of VSC-HVDC System

VSC-HVDC is used for"North-South Power Exchange", which is a new mothed and need to adjust its characteristics and its key technology for in-depth study. Based on the analysis of the basic principles of PWM control, the constant frequency is achieved; the impact of active power on voltage is analyzed from both qualitative and quantitative; the impact of reactive power on voltage is analyzed qualitatively. As VSC-HVDC system for the realization of power grid peak load mutual regulation and the emergency power support, the load flow flips at any moment. Based on Lyapunov stability theory, through unilaterally controlling active power according to the frequency of AC system in the vicinity of rectifier of VSC-HVDC, and bilateral coordination control to limit the size of the load flow, the load flow automatic soft flip of VSC-HVDC is realized. The simulation results show that, VSC-HVDC system used for power grid peak shaving and emergency power supportting can make the trend reversal relatively stable, reducing the shock for DC voltage, reactive power and AC voltage.