Impacts Of Large-scale Wind Power Integration On Voltage Stability And Corresponding Solutions

As one of the most mature and cost-effective resources among all renewable energy, wind power has experiend remarkable growth these years. Because of the uncertainty and randomness of the wind energy, the influences of the wind power, especially on the voltage are paid more attention with the growing of the installed capacity of wind farm. it is important to focuse on the impact of large scale integrated wind power on voltage stability. The main content of this thesis covers following:A. Deeply research the static and dynamic models of Doubly-fed induction generator (DFIG). Under the constant power factor control mode, the power flow calculation methods for grid including the wind power are established.B. Sensitivity analysis and PV, VQ analyses are used in power systems including wind farms. Furthermore, the transfers of the voltage weak nodes and weak transmission lines before and after the integration of the wind power are researched. Based on real examples, the differences and similarities of sensitivity analysis and PV, VQ analyses are compared. Also, the impacts of the different volumes of wind farm outputs and wind power factors on the grid voltage stability are investigated.C. Differential Evolution is used in the reactive power compensation of the wind power system, which calculates the compensation volumes of the voltage weak nodes from the results of sensitivity analysis and PV, VQ analyses. The corresponding calculation program is written. Based on these, the reactive power compensation strategy considering large-scale wind power is built. Also the influences of the different evolution strategies are researched.D. Based on PSS/E and real grid data, the differences between the strategy promoted in this article and the original reactive power compensation strategy are compared. In order to prove the effectiveness of the promoted strategy, the change of the bus voltage during the wind speed fluctuation, load change and faults are studied.The results of this research have been used in real project, which is proved effectiveness.