Research on Reactive Power Compensation of Grid Connected System of DFIG Based on RTDS

The paper builds a digital dynamic model of real time wind power grid system that STATCOM joined up DFIG on the platform of RTDS, analyses the main circuit and the control system of STATCOM, builds high voltage STATCOM model with small time step. According to the analysis on the converter theory of DFIG, control system of the grid side converter and the rotor side converter is constructed. Finally, STATCOM is connected to DFIG real time wind power generation system through a three-phase breaker. The study shows that various parameters will increase and vi brate largely when STATCOM is connected to the grid connected system of DFIG, including the grid current, stator side current, rotor side voltage and current, the reactive power and active power which are sent to the grid. Then, all of the parameters will return to normal after aperiod of time. The DFIG grid connected system with STATCOM can effectively overcome the voltage drop caused by the sudden change of wind speed and improve low volta ge ride through (LVRT) capability ofDFIG.