Coordinated Droop and Virtual Inertia Control of Wind Farm for Frequency Regulation

The variable speed wind turbine generator (VSWTG) can’t change its power output to respond to the system frequency change, and has no power reserve while operating at Maximum Power Point Tracking (MPPT) mode. On the premise that the wind farm operates under deloading control obtaining power reserve, a coordinated control method is proposed which combines droop control and virtual inertia control. When setting the droop coefficient, the influence of the power reserve capacity of wind farm on the droop coefficient setting under two different conditions, load increases and load reduces, is considered respectively. When setting the virtual inertia coefficient, different virtual inertia coefficients are adopted in different time periods. The simulation results show that the static and dynamic characteristics of system frequency are efficiently improved by wind farm based on the proposed coordinated control method.