Integrated Optimization Of Wind Power Installed Capacity And Reactive Power Considering Static Voltage Stability

With development of industry,fossil energy is becoming increasingly depleted.wind energy is a kind of renewable energy,which is free of contamination,reasonable use of wind energy is beneficial to save fossil energy.Optimizing installed capacity of wind farms is beneficial to the rational use of wind power.Under existing grid condition,wind power penetration limit is calculated in this paper considering both static voltage stability and the wind power acceptance capacity of the power network connecting with the receiving end of wind power transmission line;then,on this basis,considering reactive power optimization,so as to improve static voltage stability and improve the wind power receiving capacity of the power network connecting with the receiving end of wind power transmission line.This paper mainly includes the following contents:(1)The acceptance capacity of the power network connecting with the receiving end of wind power transmission line is less considered when calculating wind power penetration limit considering static voltage stability.Using maximizing installed capacity of wind farm and maximizing static voltage stability margin in the rated output level of wind farm as two objective functions,considering static voltage stability limit and the power flow limit of public grid,a multi-objective chanced constrained model is established.The NSGA-II algorithm based on Pareto optimal theory is used to solve the optimization model,this algorithm can effectively deal with the conflict between two objective functions through non-domination sort.A non-dominated solution set shrinkage method is proposed to set the capacity of STATCOM in wind farm,then the effect of wind farm reactive power support in improving static voltage stability of power system is analyzed.The corresponding load margin of chromosome sample is estimated by using the trained neural network.Calculation results show that,wind power penetration limit is reduced with the increase of system stability margin requirements,if do not consider reactive power output of wind farm;Considering the reactive power support capability of wind farm can improve the static voltage stability of power system,weakening the constraints of stability margin on the installed capacity of wind farm.(2)To more fully reflect the wind power acceptance capacity of the power network connecting with the receiving end of wind power transmission line,based on the above research,considering optimally configurate STATCOM and UPFC,thus reflecting the effect of reactive power compensation on static voltage stability and wind power acceptance capacity of power system.The existing active power optimization model and reactive power optimization model are combined to establish the active-reactive power decoupling optimal power flow model,considering static voltage stability.The objective function of active power optimization is maximizing net income of the wind farm and minizing average coal consumption amount per hour of the system.The objective function of reactive power optimization subproblem is minizing wind power collection bus voltage deviation,minizing STATCOM compensation capacity and minimizing line load rate.An improved static voltage stability index LSZS is derivated using the existing method,and the static voltage stability constraint is established using this index.Active power optimization subproblem and reactive power optimization subproblem are alternately solved.The results of IEEE 39 bus system show that,after considering the influence of the step-up transformer and transmission line of wind farm,it is possible to obtain a more conservative result if only conducting active power optimization;through integrated optimization,installing STATCOM in wind farm and installing UPFC optimally in the public grid line associated with the wind power access point,a scheme with higher wind farm net income can be got.