Research On Wind Power Fluctuation Characteristics And Its Impacts To Voltage Stability

Because of the randomization and uncertainty of wind, the output power of the wind generator is not stable. When the wind farm is connected with the power grid, enough reserve capacity is essential, so that the output of wind power is insufficient, the system could provide enough power to the customers. The fluctuation of the wind power should be tracked so that the reserve capacity could be certain, however, the fluctuation of the wind power brought tremendous impact to the wind farm. Therefore, with large scale wind farm connected to the power system, wind power forecasting will play a more important role in both system planning and stability maintenance. In view of the above problems, the following work is done:1) The time series method and Kalman filter are used in wind prediction. First the time series method and mathematical models are summarized. The Kalman filter is introduced for raising the accuracy of time series prediction, which is too low as well as prediction delay exist. First the time series equations based on historical wind speed data are got, then the coefficients of the predicting equations are put into the Kalman filter equations so that the wind speed forecast data of the next stage can be obtained.The simulation results shows that this method can effectively improve the wind speed forecasting accuracy.2) The wind speed data of Yantai is gotten from NASA GEOS-5 DAS database, so that the wind power fluctuation characteristics could be analyzed. The seasonal and days fluctuation characteristics of Yantai in the key section should be analyzed.3) The stability of the power system is summarized, then the simulation model of the power system including wind power is set, so that the voltage stability of the system in terms of gust disturbance and transmission line fault can be analyzed; at the end, the simulations of two kinds of reactive power compensation device(STATCOM, SVC) are done.4) Based on the principle of bifurcation theory, solving methods of voltage stability process, local bifurcation type, bifurcation point and bifurcation boundary analysis using bifurcation theory are given; then the principle of Static Var Compensator(SVC)and high pass filter(washout filter) are introduced; Finally, the simulation model of the power system including wind farm is built, the influence of Static Var Compensator(SVC) parameters to the voltage stability of the system, the effect of static var compensator(SVC) containing high pass filter(washout filter) to voltage Hopf bifurcation of the power system including wind farm can be got.