Visual Linearized Model Of Power System Containing FACTS And Its Application

Flexible AC Transmission Systems (FACTS) can greatly enhance the reliability and controllability of the power system, also can largely improve the transfer capacity and the power quality of grid. The development and application of FACTS technology added more means of control to power system, which also made the system more complicated, raised more new issues of power system small signal stability. How to establish a concise and practical model of power system containing FACTS devices has become a matter of concern. In this thesis, visual linearized models of power system (single-machine c₁～c₁₂ model, multi-machine C₁～C₁₈ model) were extended. The linearized models considering the effect the damper windings and incorporating FACTS devices were established, which were applied initially in power system small-signal stability analysis. Main achievements are as follows:In this thesis, an extended c₁～c₁₂ model incorporating SVC was established. Based on this model, the expression of the damping torque of SVC is given, eigenvalues of single-machiane-SVC-infinitebus power system are calculated, and damping characteristics of SVC in different operating conditions are discussed. The research indicates: the damping effectiveness of SVC will go up along with active load increasing and will diminish along with AVR gain increasing. When active load is low and AVR gain is high, the damping effectiveness is the weakest, but not negative.In this thesis, an extended c₁～c₁₂ model incorporating TCSC was established. Based on this model, the expression of the damping torque of TCSC is given, the damping characteristics of TCSC in different operating conditions are analysed, and also the impact of damping control strategy on damping characteristics of TCSC is discussed. The research indicates: the damping effectiveness of TCSC will go up along with active load increasing and will diminish along with the transmission distance increasing. In order to guarantee TCSC provide positive damping to power system, the proper control strategy is necessary. In this thesis, an extended c₁～c₁₂ model incorporating UPFC was established, which was compared and unified with extended c₁～c₁₂ models incorporating SVC or TCSC. At last, the unified extended c₁～c₁₂ model incorporating FACTS devices was given.In addition, for multi-machine power systems installed with SVC, TCSC or UPFC, an extended C₁～C₁₈ model incorporating SVC, an extended C₁～C₁₈ model incorporating TCSC, an extended C₁～C₁₈ model incorporating SVC and TCSC, and an extended C₁～C₁₈ model incorporating UPFC were established respectively. These models offer a foundation for further research on the characteristics of FACTS devices in multi-machine power systems.