Research On The Influence Of Large-scale Wind Power Grid Connection On Voltage Stability Of Power System

As a clean energy,wind energy has been well known and utilized by people.In the past 20 years,China has made great progress in the development of wind energy,which plays a good supplement to conventional energy.At present,China has built or is building 10 wind power bases with installed capacity of 10 million kilowatts.The larger the scale of wind power is,various problems will occur when the wind power is connected to the grid.Among them,the voltage stability after the wind power is connected to the system is a major problem.Starting from the analysis of the overall active power output of the wind farm,the reactive power characteristics of the wind farm,and the voltage characteristics of the wind farm and the transmission network,this paper calculates the power flow distribution of the power grid after the wind power is connected to the system,and then obtains the static voltage stability limit point of the large-scale wind power system.In this thesis,the active power output of wind farms and wind farm groups are analyzed respectively.The analysis of wind farms mainly considers the wake effect among wind turbines,while the analysis of wind farm groups mainly considers the correlation,simultaneous rate and smoothing effect among wind farms under the multi-spatial scale.Second on the wind farm reactive power characteristic and node voltage characteristic is analyzed,the paper analyses the characteristics of the wind farm reactive power is mainly wind turbines and reactive power transmissio n equipment throughput,the reactive power of the wind farm group characteristics,and the reactive voltage characteristics such as internal wiring of wind farms,the paper analyses the characteristics of the and node voltage is mainly caused by wind power grid voltage,active and reactive power output change fluctuation of voltage,and the influence of the mass to take off the net after wind power grid voltage characteristic.On the basis of the above analysis,combined with the characteristics of large scale,high concentration and long distance of wind power grid connection,the local parameter continuous power flow algorithm is used to solve the static voltage stabilit y limit point of the system.Finally,the simulation calculation is carried out for the group access system of JiuQuan wind power base.This thesis proposes an improved algorithm for two shortcomings of the local parametric continuous power flow algorithm.Namely,the Newton-raphson method is reduced to PQ decomposition method and the quadratic curve fitting method is used to find the voltage stability limit point,basis and steps of improvement was deduced in detail,and the original example by improved algorithm simulation calculation,t he calculation results show that under the premise of guarantee calculation precision,its computation time is very short,is suitable for on-line power flow calculation.