System Voltage Stability Analysis And Reactive Power Optimization Considering The Correlation Of Wind Farms

In recent years,in order to alleviate the increasingly serious energy crisis and environmental problems,the development and utilization of new energy has attracted much attention.Among them,wind energy has been vigorously promoted for its rich reserves,green and clean advantages,and the development and utilization technology of wind energy is currently the most mature.However,due to the strong randomness and volatility of wind power,the output power of wind farms is less controllable,and the proportion of wind power connected to the grid is higher and higher,which has a huge impact on the stable operation of the static voltage of the power system.Therefore,it is very important to study the voltage stability analysis methods and improve the voltage stability measures in the field of power system analysis and control.This paper studies this problem.Firstly,the influencing factors of power system stability are analyzed,and the influence of fan output and load on system voltage stability is described by theoretical analysis,and its probability model is established.Secondly,considering the correlation of the output power of the wind farm and obtaining the probability and statistics information of the output variables,the probabilistic power flow algorithm based on the three-point estimation method is improved by using the principal component analysis method and Cornish Fisher series expansion method.In the calculation example,by comparing with the algorithm dealing with the correlation by using the Cholesky decomposition method,it is verified that the method has higher calculation accuracy,calculation efficiency and Practicability.Then,the L index is used to evaluate the static voltage stability of the wind power grid connected system.Based on the L index,the sensitivity to the injected power of each node is derived.Taking the IEEE39 node system as an example,considering the randomness and fluctuation of wind power output and load,the improved probability tidal current algorithm is used to obtain the probability statistical information of the L index of each node Stability risk,find out the system instability node,provide a more reliable basis for the wind power grid connected system to improve the static voltage stability and take compensation measures.Finally,based on the weak node of system voltage stability,the reactive power optimization model is established with the expectation of active power loss and the expectation of system L index as the optimization objective,and the improved flower pollination algorithm is used to solve the problem.Through the comparative analysis of the results before and after the optimization,the accuracy and effectiveness of the model are verified.