Frequency Stability and Control in Island Operation Using Wind Power

This paper evaluates the impact of wind power frequency control in an island system with wind and hydro generation using PSS/E simulations. The paper considers both grid-to-island transitions and the subsequent continuous island operation. Inertia emulation during the transition, using the kinetic energy in the wind turbines, reduces the frequency nadir by 13% and reduces frequency variations during continuous operation without major power losses. De-rating the wind turbine, providing a reserve and adding a droop control in addition to the inertia emulation further improves stability, with droop control reducing the variations in the frequency during continuous operation by 47%. Additionally, in the wind farm scenario, power variations due to wind speed changes are reduced, lowering frequency variations by 20.6%.