Research Of Static Voltage Stability Of Power Network Containing Wind Farms

A method based on the principle of superposition and semi-invariant to calculate the load margin probability distribution is mainly researched in this paper, and it is applied to the power grid with wind farms static voltage stability analysis. Firstly, aiming at the randomness of the wind power, a wind power output probability model is gotten, which is using a mathematical model of wind speed with a Weibull distribution characteristic. Secondly, the principle of superposition and semi-invariant are used to calculate the semi-invariant of load margin percentage, the results are superimposed to expand Gram-Charlier series for getting the distribution of the load margin. Then the voltage instability probability in the system is calculated. Thirdly, a calculation process is given on the basis of the method, and then the voltage instability probability of an IEEE14 node system after the wind farm is calculated. Finally, An IEEE14 node simulation example is built to calculate the results of the proposed method and Monte Carlo method. It shows that the method used in this paper is correct by comparing the analysis.