Stabilization of Wind Farms Connected with Multi Machine Power System by Using STATCOM

Abstract

In this work, steady state characteristic and transient stability of wind turbine generator system (WTGS) are analyzed in detail with using a power system model, in which two wind farms are connected with multi-machine power system. At each wind farm terminal one three-level PWM based STATCOM is connected. Fuzzy logic controller (FLC) is used as the control methodology of the STATCOM. Since shaft system modeling of wind turbine has a significant effect on the transient stability analysis of WTGS, two-mass shaft model is adopted in this study. The capacitor bank capacity of wind generator is reduced by 15 percentages when STATCOM is installed at wind farm. As wind speed is always fluctuating, the terminal voltage of wind generator also fluctuates randomly, which has an adverse effect on the rest of the power system. It is reported that the STATCOM with reduced capacitor bank can decrease the voltage fluctuations of multi-machine power system as well as wind generator terminals. Moreover, it is shown that STATCOM can also enhance the transient stability of induction and synchronous generators when a network disturbance occurs in the power system. Both of the symmetrical and the unsymmetrical faults are analyzed. Both multi-wind generators wind farm and aggregated single generator wind farm models are used for the sake of detailed analyses. Finally, it is concluded that the STATCOM can enhance both of the steady state characteristic and transient stability of wind farms connected with multi-machine power system.