Wind Turbines with DFIG Participate into Primary and Secondary Frequency Control by Suboptimal Power Tracking Method

Due to the installed capacity of wind power generation has been increased ceaselessly in all over the world, the wind power in power systems rises with high penetration. When the wind turbine with DFIG participates into frequency control in the power systems, in order to meet the demand, the DFIGs usually operate in de-loading condition. Thus, a strategy that DFIG uses suboptimal power tracking method to reserve active power for reducing economic loss of wind farm and let DFIGs to meet the capacity requirements of frequency control need to be realized. This paper only requires DFIG to participate into frequency control at high wind speed and set threshold of frequency control based on the economical setting when DFIG working in the high wind speed. According to frequency quality requirements of power grid and the frequency regulation capability that the DFIG needs to provide, the output active power of DFIG is traced to the suboptimal power curve to keep a certain adjustment margin for primary and secondary frequency control. The simulation results show that the proposed strategy could effectively improve the system frequency characteristics.