Load Frequency Control Of Power System With DFIG Wind Turbine

With the development of wind power, the proportion of wind power in the power grid is increased constantly. Due to the dynamic and stochastic characteristics of the wind power generation, the influence of large-scale wind farms on system frequency should be taken into consideration. Moreover, active and reactive power are decoupled in double-fed variable speed wind turbines, which makes it hard to participating in the frequency regulation as the conventional generation units. To solve the problems, this paper studies of the load frequency control of interconnected power systems with wind turbine.First. a simplified model of wind turbine is proposed. This model is simple but captures the essential dynamics of the wind turbine, and it is suitable for the study of LFC of poer systems with wind turbine. Active Disturbance Rejection Control (ADRC) and Internal Model Control(IMC) are applied to design LFC controllers for interconnected system with simplified wind turbine model. Simulation results show that LFC with wind turbine participation can improve the speed of system response, and regulate frequency faster. Moreover, ADRC is more suitable for systems with model uncertainty.Secondly. two control strategies for wind turbine involved in the primary frequency regulation are proposed:inertia control strategy and droop rate control strategy. Comparing the performance of two control strategies. it is concluded that droop rate control strategy can inject active power quickly and balance the load demand, thus reduce fluctuations in the amplitude of frequency deviation.In order to make wind turbine return to the optimal speed after frequency regulationADRC controller is used to control the rotate speed.. The results show that ADRC results a faster optimal rotational speed return than PI controller while reducing the regulation time and overshoot involved in system frequency regulation.