Research On The Active Power Control Of Wind Farm Considering The Optimization Of Pitch Action With Multi-time Scale

As a result of the increasing wind power penetration on power systems,the fluctuation and intermittence of wind power has brought about enormous pressures and extremely challenges to the optimal operation and dispatch of power grid.In order to reduce the adverse effects of large-scale wind power integration on power system,the wind farm is required to be more controllable to meet the more stringent technical requirements specified by system operators,including active power control.Researching and improving the Active Power Control system of wind farm,is significant for the stable and economic operation of power grid,and conducive to mitigate the problem of abandon wind.This paper focuses on the Wind Farm Dispatch Center and Wind Turbine Control System of wind farm Active Power Control System,and the specific work is as follows:For the existing active power control(APC)methods of variable-speed variable-pitch(VSVP)wind turbine generators(WTG),they do not make the best use of the turbines aerodynamic characteristics to optimize the operation conditions in high speed,which can easily lead to mechanical fatigue caused by the frequent pitch actions.A novel APC for WTGs is proposed in this paper,which can consider both the power control effect and the operating conditions of wind turbine.The proposed strategy optimizes the mechanism of pitch regulation,which can effectively decrease the frequency and amplitude of the pitch actor,thus to extend its operating life.Associated simulations are presented and compared to verify the feasibility and effectiveness of the proposed control strategy in Matlab/Simulink.For the wind farm power generation scheduling error caused by fluctuations and forecasting errors of wind,the paper presents a two-layer coordinated control framework for wind farm active power control under multi-time scale,including the upper level global optimal dispatch strategy in a long-time scale and the lower level real-time modification control strategy in a short-time scale.The global optimal dispatch strategy overall considers the prediction information,operation conditions and control characteristics of wind power generation units within wind farm,and a multi-objective optimization model intends to minimize the wind farm power generation scheduling error,the frequency of start/stop of WTGs and the number of control system's actions of WTGs is established,which to realizing the economic operation of wind farm.Based on the unit scheduling orders given by the global optimal dispatch strategy,the real-time modification control strategy utilize the units,which still has power regulation margin,to mitigate the active power fluctuation of wind farm caused by fluctuations and forecasting errors of wind,which enhance the stability and reliability of the output of wind farm power.At last,the effectiveness of the propose control strategy has been verified by comparing with the variable proportional division method.