DFIG Wind Turbine Modeling And Its Load Frequency Control

With the development of wind power, the proportion of wind power in the power grid is increased constantly. Doubly fed induction (DFIG) can decouple the active power and the reactive power quickly, can operate in a wide range of wind speed and with maximum wind energy capture, thus it is widely used in large wind farms. Due to the decoupling of turbine speed and power grid frequency, DFIG can not respond to changes in system frequency. Lots of wind farms based on DFIG access to the grid and replace tradional synchronous generators, which will reduce the ability of the frequency control. With wind power penetration levels increasing, problems have become increasingly serious.To solve the problems, this paper studies of the load frequency control of interconnected power systems with wind turbine.Firstly, using Simulink/Matlab as simulation tool for DFIG basic modules and double-fed asynchronous generators are analyzed and simulated. Different control methods are carried out for the wind turbine under different wind speed. The simulation results are satisfactory.Secondly, According to the disturbance of wind power generation in power system, a new method of flywheel energy storage control is presented. Simulation results show that with the flywheel assisted, wind turbine-flywheek system can participate in the load frequency control.Finally, two control strategies for wind turbine involved in the frequency regulation are proposed:inertia control strategy and droop rate control strategy. The fluctuation of wind speed is considered. Wind turbine in load frequency control is controlled by the two strategies and wind turbines can make contribution to the frequency of the power grid.