Study On Capacity Optimization Of Transmission Of Wind Farm Group

Wind power has a lower energy density,and is fluctuant,intermittent and uncertainty.If the power transmission capacity is planned by the total installed capacity of the wind farm group,it is likely to cause excessive allocation of transmission capacity and reduce the operating efficiency of the transmission system of wind power.However,if the transmission capacity allocation is too low,it can not only reduce the cost of investment,but also maybe result in abandoned wind loss caused by transmission congestion when the overall output in the wind farm group is larger in part time.Therefore,how to balance many influencing factors in the transmission project planning and reasonably design the capacity of the ancillary transmission lines is an urgent problem to be solved.The main contents of this paper are as follows:Firstly,this paper uses Copula function for each wind farm's distribution of wind speed.In the case of a long span of time,the wind speed distribution in different periods is not exactly the same,so the unknown parameters of the speed distribution of Weibull and Gumbel Copula are estimated at each stage for the joint distribution of the corresponding.Latin hypercube sampling is used to the obtained Copula joint distribution of speed,and the wind speed curve is obtained.Using the function of relation between wind power and wind speed,output power of each wind farm is gained.Gathering the output power of each wind farm to obtain the power curve of the wind farm group.Finally,the power curve of each period is arranged from large to small,and the continuous output curve is obtained.Based on the continuous output curve of wind farm group,considering the income of power transmission,construction cost of power transmission project and abandoned wind loss due to transmission congestion,a delivery model of pure wind power transmission with comprehensive income is established.The example shows that the proposed model can not only reduce the transmission project investment,but also improve the utilization ratio of transmission lines.Considering the wind power supply of the pure wind power has large fluctuation,and can not meet the "Technical regulations for wind farm integration into power system ",therefore,in the actual wind power output data,the reasonable configuration of power transmission capacity and storage capacity is given based on CVaR,at a certain confidence level,which made the fluctuation of wind power output accord with the technical requirements and improve the wind energy utilization rate.The example shows that the proposed model can not only reduce the transmission capacity and investment.Decision makers can select reasonable levels of confidence in accordance with the abandoned wind power and punishment power to optimize power transmission capacity and the allocation of capacity and power of storage.Finally,considering the comprehensive of income transmission project and the qualified rate of wind power fluctuation,this paper uses particle swarm algorithm to obtain a series of Pareto optimal solutions for the formation of the Pareto frontier,and then uses the ideal point method on choosing the compromise optimal solution from the Pareto front.The optimal transmission capacity and the energy storage system is obtained by solving optimization model of wind farm group delivery.