The High Permeability Distributed Wind Storage System Participates In The Research Of Grid Frequency Regulation

Wind power has the advantages of mature technology,low cost and safety,it has become the most competitive new energy power generation technology.There are two main forms of wind power generation:wind farm and distributed wind power.Distributed wind power is connected to the distribution network in the form of a single or several wind turbine,combined with energy storage to form a wind power microgrid,which can increase the controllability of distributed wind power,and also increases the possibility of providing ancillary services for the grid.In this thesis,when distributed wind storage systems connected to different distribution networks,the following possible auxiliary services may proposed.When connected to the strong distribution network,provide timed constant power flow of microgrid tie-line function.When connected to the weak distribution network,providing timed constant power flow of microgrid tie-line function,as the same time providing the function of participation in the primary and secondary frequency regulation according to the need of power grid.The auxiliary function can not only increases distributed wind power consumptive capacity,convenience management of high penetration of distributed wind power distribution network,but also improve the stability of weak power grid operation.Through two kinds of wind storage system topology comparison,the structure of the wind-battery system is determined.When the energy system is connected on AC side,the hardware control between the wind turbine and the energy storage system is completely decoupled from each other,it is easy to achieve,the technology is relatively mature,and reducing a level of energy conversion,more economical,easy to centralized control.Meanwhile,aiming at the active frequency weak inertia of the traditional variable speed wind turbines,a frequency loop is designed and added to the power controller of the rotor side of the wind turbine,which greatly increases the inertia of the system.Based on distributed wind-energy storage system,this paper propose a hierarchical control strategy.A central controller can detects the wind speed,the rotor speed and the grid frequency in real time and realizes the switching of the system mode and the selection of the bottom controller in different running states.The local controller includes wind power MPPT control and energy storage power control.In the aspect of wind power fluctuation,the energy storage system can help the wind generation system to connect to the power grid,which can make the wind-storage system output power smoothing;in frequency regulation aspect,considering wind speed and energy storage configuration,combining inertia control and energy storage to participate in the power grid frequency regulation.Based on the Matlab/Simulink simulation environment,this paper have designed and built MW permanent magnet wind generation system model,energy storage system model,power grid model and related local controller model.The use of Stateflow toolbox for operation state transition strategy has realized the coordination control system operation mode selection and controller switch.By using the measured wind speed curve,the wind storage simulation system is established.The simulation results verify the correctness and effectiveness of the proposed control strategy.