Wind Farm Active Power Optimizing Dispatch And Control

Wind energy is one of the important ways to solve the increasing shortage of fossil resource and environmental pollution.In recent years,the installed capacity of wind power is increasing day by day,especially,the offshore wind energy project has been increasing faster than onshore wind energy.With the increasing penetration of wind energy,it brings huge challenges to the safe and stable operation of the power system,due to wind energy is fluctuation,intermittent,uncontrollability,and unpredictable.And grid-connected wind farms have the capacities of active power regulation and primary frequency regulation by the grid codes.At the same time,the wake effects of wind farms will decrease the overall captured wind enengy.In order to protect the safe and stable operation of the power system,and increase the competitiveness of wind power,wind farms have to improve the level of active power control.A wind farm active power dispatch center receives active power command of a power dispatch center,and it sends simultaneously active power commands to every wind turbines by a dispatch algorithm.A suitable dispatch algorithm can meet the requirements of power grid dispatching center,increase active power quality,reduce the fatigue loads of wind turbines,and increase the active power out of offshore wind farms.Further more,ensure the safety and stability of the power system,decrease the cost of wind turbines,and improve the economic of wind farms.So this paper researchs the power limit control of wind turbines,the dispatch algorithms of wind farm,primary frequency cooperation control of wind farm,the offshore wind farm clustering algorithm,and the maximum power tracking method of wind farm.The main contents are as follows:1.In order to reduce frequent pitch regulation of conventional active power limit control algorithm,this paper proposes an active power regulation algorithm based on the pitch inactive region.Firstly,a wind turbine mathematical model is establish to provide a basis of power limit control,wind farm active power dispatch,and so on.Secondly,a pitch inactive region is obtained by analyzing the operation characteristic of wind turbine power limit control,and a rotational speed error compensator is designed by considering the pitch inactive region.The simulation results show that,comparing with the traditional PID algorithm and the variable pitch variable speed coordinated control algorithms,the proposed algorithm can satify the power limit requirements,and reduce the pitch regulation.And it is easy to use in reality.2.There is a problem of large fluctuation of wind farm active power out and frequent adjustment of pitch system in the conventional wind speed weighting wind farm active power dispatch algorithm.And the wind turbine curtailment power operation is divided into variable speed,variable speed joint variable pitch and variable pitch operation zone,the input of fuzzy evaluation are the pitch angle,rotating speed and wind speed,get every wind turbine's capacity of schedule and regulation by piecewise fuzzy inferring.In the end,the active power dispatching algorithm based on the weighting of capacity of every wind turbine.The simulation shows that,through the active power dispatching algorithm based the fuzzy evaluation,the out power of wind farms is smoother,and decrease the amplitude of pitch angle of wind farm.3.The fuzzy evaluation wind farm active power dispatching algorithm relies on the experts'experience,and it is shortcomings of subjective.A wind farm active power dispatching algorithm was proposed,which based on data-driven algorithm.Firstly,the data of rotational speed and pitch angle was obtained at different wind speed.The relative weighting coefficient of variable speed system and pitch system was evaluated by the coefficient of variance method and TS fuzzy model at full-range wind speed,and got the adjustment capability.The active power dispatching algorithm based on the adjustment capability of wind turbine.Lastly,the active power dispatching algorithm of wind farm with 10 wind turbines was completed in MATLAB.The simulation results show that,comparing with the fuzzy evaluation dispatching algorithm,two active power dispatching algorithms results are same.But the calculation time of data-dirven active power dispatching algorithm is shorter.4.There are problems of low wind farm efficiency and sub synchronous oscillation,when all wind turbines participate the primary frequency of power system.This paper proposed a wind farm primay frequency coordinate control algorithms based on the operation status of wind turbines.Firstly,according to whether a wind turbine can release rotating energy storage and whether it can increase the capture of wind energy,wind turbines are divided into non-adjustable region,weakly adjustment region,general adjustment region,and priority adjustment region.Thereby,wind turbins of non-adjustable region and weakly adjustment region don't participate primary frequency regulation,wind turbines of general adjustment region can participate primary frequency regulaton only by themselves,and wind turbines of priority adjustment region have priority to be dispatched by wind farm active power control center.At last,the wind farm primary frequency coordinated control algorithm is completed by the frequency regulation classification of wind turbines.The simulation results show that:the primary frequency regulation effect of the proposed algorithms is better than the all wind turbines participating primary frequency regulation strategy,avoid the the secondary drops of system frequency,and reduce the sub synchronous oscillation of wind farm.5.There are disadvantages of large amount of calculation and sensitivity of noise in wind farm maximum energy tracking with wake effects by using traditional difference method.In order to reduce the calculation time of wind farm maximum energy tracking algorithm,and overcome the "noise amplification effects",this paper proposes a miximum wind energy tracking algorithm based on singular value decomposition and tracking differentiator.Firstly,wind farm wake relationship matrixes are established considering the wake effect in an offshore wind farm,and the SVD of wake relationship matrixes is used to cluster wind turbines into some groups by the fuzzy clustering algorithm.Secondly,he tracking differentiator obtains the gradient information of the wind farm according to the power output of the wind farm and the wind turbines active power command,and finally completes the maximum wind energy tracking by gradient information.The simulation results show that:the clustering method can reduce the calculation time,and compared with the traditional difference method and the extremum seeking method,the proposed algorithm can effectively increase the active power output of the wind farm,while reducing the pitch action and fatigue load of the wind turbines.