Research On Reactive Voltage Control To Improve The Stability Of Wind Farm Systems

As major form of distributed generation, wind power becomes popular because it has the characteristics of renewable, wide distribution, cleanness and so on. With the rapid growth of the scale of development, the competitiveness of wind power market will be improved in the future.As renewable energy, although the wind power has many advantages, it also has many natural attributes such as volatility and randomness. Compared with the mode of traditional energy generation, the stability of wind power generation is poor. With the increasing scale of wind power generation, the higher the voltage level of the access network, the influence of the grid connected wind farm on the voltage stability of the power grid is greater, so we need to research on voltage stability of wind farm system.The main research contents are as follows: Through the comparison of three kinds of wind turbine, it turns out that the doubly fed induction wind machine has better economy and technology. The steady-state model of the double fed induction wind generator is established, and on the basis of this model, the active power and reactive power of wind generator to the system are calculated. From the aspect of static stability, the mechanism of voltage stability is analyzed,this paper introduces, the analysis methods of static voltage stability and some indexes of commonly used static voltage stability. Besides, the static index L based on the solution of power flow is elaborated primarily. The problems of voltage stability in wind farms connected system are analyzed by using the method of static power flow. It turns out that in order to maintain the voltage level, the wind power system needs the control of reactive power to improve voltage stability of wind power. The method of reactive power and voltage control is proposed,considering the margin of voltage, the economy of reactive compensation, the level of voltage.According to the optimization results, the control center of power system can send commands respectively to farms and other reactive power compensation equipment to reasonably compensate reactive power, which can optimize the voltage stability margin of wind power system on the basis of the method of multi-objective reactive power and voltage control.The systems of improved IEEE-14 bus IEEE-30 bus are as examples to be analyzed by using the MATLAB software. Through compared with the other two proposed control methods, the results shows that the proposed reactive power and voltage control scheme is effective.