Control study of wind farm integrated to weak grid by VSC-HVDC

The reactive and active power variation of grid- connected wind farms leads to voltage and frequency fluctuations and instability of power grid. The voltage and frequency control model of Voltage Source Converter HVDC (VSC- HVDC) was proposed to overcome this problem. The mathematical model of wind farm integration system was systematically built. The control link of VSC-HVDC converter WFVSC and GSVSC was well designed. The frequency link was also added to the traditional control model of voltage and power outer loop control and current inner loop control to solve the problem that double fed variable speed wind turbine could not response to frequency variation when the grid frequency changed. The test system of wind farm integration by VSC-HVDC to grid was established, the corresponding HVAC integration was applied for comparison, and wind speed fluctuations and fault were simulated. The simulation results verify that the proposed control model of VSC-HVDC is correct and valid based on test system.