Impact of wind speed disturbance on power system frequency stability

When wind generator is integrated into the power system, it will not only change the system´s inertia but also introduce a lot of randomness to the active power output of wind farms. This is due to the wind speed disturbance which wind farms has always suffered from. Hence the large-scale wind farms integration into the power system will results in profound influence on frequency stability. This paper focuses on the study of frequency stability of a power system integrated with large-scale wind farms under different wind speed disturbance scenarios. A comparison of dynamic frequency response characteristics during the period when the wind turbines experience random noise disturbance, ramp events and generator trips in the power grid with two different wind turbines which are doubly fed induction generator (DFIG) and direct drive synchronous generator (DDSG) is made. The simulation results indicate the wind speed disturbance significantly influence the frequency of power grid. The advantages of DDSGs over DFIGs are that they reduce the impact of wind speed random noise disturbance and ramp events are significant. Nonetheless, the DFIGs are less likely to tripping from power grid when the wind speed is high.