The Research And Application Of H₂/H_∞ Control In Power Systems

Modern power systems are typical nonlinear, high dimensional, dynamic and giant-scale systems. With the increasing of the transmission capacity and the interconnections among different power systems, a lot of issues on systems security and stability are raising up.SVC is important in power systems. It can improve the voltage stability, increase the capacity of transmission power in long distance and high voltage systems, supply enough dump, dump system oscillation, lower over voltage, enhance static and dynamic stability. Fast turbine valve is a strong way to keep power systems transient stable and steady. This method cannot take the place of cutting off steam turbines which is not hoped if it's used appropriately. SVC and turbine valve control are the main methods to keep power systems stable and secure.In this paper, based on existed control theory and the application of the H2/H∞control in power systems, the H2/H∞control rule in power systems is designed. The H2/H∞control has good robustness and performance. This controller based on the H2/H∞control improves the voltage characteristics at the location of SVC greatly, has good robustness, damps the system oscillation and improves the stability of power systems.Three ranks SVC model is built. Considering the uncertainty in power systems, the perturbation matrix is added in the model. The H2/H∞SVC controller is designed based on the H2/H∞control theory. In the three-phrase short simulation, the transient responses of the main parameters of the H2/H∞controller and the conventional controller are compared and analyzed.The four ranks turbine valve model and the five ranks coordinate control model are built. Based on the H2/H∞control theory, the turbine valve controller and the coordinate controller of SVC and turbine valve are designed. In the three-phrase short simulation, the transient responses of the main parameters of the system with the H2/H∞controller and the conventional controller are compared and analyzed.The result demonstrates that compared with conventional controller, the H2/H∞control makes the overshoot smaller and down time shorter and enhances the voltage characteristics. The H2/H∞control is fit for the practical model of power system, can dump systems oscillation quickly, improve the dynamic performance stability of power system and voltage characteristics at the location of SVC greatly and has good dynamic quality and robustness.