Application Of Parametric Method On Power System Robust Controller Design

With the implementation of the national grid interconnection, the complexity of power systems is growing. Because of the surge capacity of the generators and the application of the new technologies, the requirements for power system transient stability raises to a much higher level. How to suppress the low-frequency oscillations of the system and enhance the stability of the power system become the urgent problems. Therefore, in order to improve and enhance the power system stability, the research and the application of the new control methods have become an important topic of power system.The robust parametric approach and the damping ratio method based on a fixed pole placement are combined in this paper. The robust parametric approach and the damping ratio method based on a fixed pole placement belong to eigenstructure allocation theory. The main idea of the robust parametric approach is to obtain the control law by establishing the parametric expression of the control law and re-optimizing the degree of freedom. The damping ratio method based on a fixed pole placement is to select the desired damping ratio and reconfiguration closed loop poles of the system by using the characteristic that no-damped mechanical oscillation angular frequency does not change before and after using the system controller.The improved parametric approach is obtained and applies to the control of the power system. This method can optimize the degree of freedom on the basis of an opposite system damping. What is more, the new performance metrics are added to the objective function according to the operating conditions of the system and the weighting factors are restricted into an appropriate range. The proposed improved method is applied into robust excitation controller and valve controller.The comparison of the improved method and the method without consideration of the pole placement shows the excellence of the improved method.Then, the improved robust parametric approach is applied to the coordinated design of power robust controller and the additional damping controller. The designed coordinated controller can adapt the change of the system structure and the perturbation of the parameters. SVC can act in concert with the excitation control by changing the line parameters of the system. The coordinated controller can improve the damping and stability of the system in a greater extent.Finally, the improved robust parametric approach is applied to the optimization of the PSS parameters and verified in a single machine infinite bus system. In the multi-machine power system, a multi-machine system decoupling model is proposedin regard to the coordination of PSS. The idea of the robust parametric approach provides a design method with the interference suppression to the robust controller.The decoupling model can suppress multi-machine disturbance and quickly quell the oscillation of the system.