Research Of FPC's Excitation Control And Its Effect On Power System Stability

The basic concept, the principle and the structure of FPC is presented in this thesis. Comparison of different kinds of FACTS devices are made for their function, the application, the cost of application as well as the advantage and the disadvantage.In order to obtain satisfactory control effect, decoupling between the active and the reactive powers is needed for the FPC. The mathematical model of FPC and its decoupling control method is presented. To realize decoupling between the active and the reactive powers, the coordinate transformation is needed. Besides, it is necessary to observe the position of magnetic flux linkage in the new coordinate system. The principle of magnetic flux linkage decoupling realized by the coordinate transformation is discussed in detail in the thesis. A new concept that the simplification of the complexity for the FPC control after coordinate transformation comes from the separation of the complexity of the original problem is proposed. According to this concept, part of the complexity for decoupling control of FPC is appended to the observation of the position for magnetic flux linkage in the new coordinate system. Several kinds of magnetic flux observation methods as well as their convergence property including the U style magnetic flux observer are discussed in detail.The thesis also investigates the steady-state stability of single machine infinite-bus power system and the ways used to improve such stability. The reason for FPC to improve the power system steady-state stability is explained geometrically. The effect of the FPC with different application position and respond speed on the steady-state stability limit is investigated by simulation and given in the thesis. The effects of the active power compensation and the reactive power compensation of FPC on the steady-state stability limit are also investigated by comparison. Power system low-frequency oscillation and its effect on power system stability are analyzed. The reason that causes the low-frequency oscillation is discussed. The capability of FPC to damp out the low-frequency oscillation is proven and verified by simulation. At last, the application and the future work about the FPC are discussed.