Chaotic Oscillation Analysis And Control Of Single Machine Infinite Power System

In recent years, with the development of the interconnections of large areas and power transmission from long distance, the complexity of operations in power system has increased. Stability problems of power system have become more complex as chaotic oscillator appears. The mechanisms of voltage instabilities and angle divergence induced by chaotic oscillation in power system have become a hot topic in the field of nonlinear dynamics. With the advent of certain parameters and disturbances conditions, chaotic behavior in power system can be found as non-periodic and irregular electromechanical oscillations which will pose a threat to the security of the power system. As a result, the research on the dynamics and control of chaos in power system is very important.In this dissertation, the dynamic behaviors of integer-order and fractional-order models in the single-machine infinite bus power system are investigated through the theoretical analysis and numerical simulations. The main research contents are given as follows:Firstly, the dynamic properties of the single-machine infinite bus system under the disturbances of periodic load and electromagnetic power are developed through bifurcation diagram, Lyapunov exponent spectrum and Poincare maps. The adaptive back-stepping sliding mode controller is designed to eliminate the chaos in power system.Secondly, the fractional second-order power system is analyzed numerically by the predictor-corrector method. The lowest order at which chaos occurs is also obtained through bifurcation and Lyapunov exponent. The overall process of the motion from stable state to chaotic motion and instability is depicted with varying the single-parameter and dual-parameter. Based on the stability theory of fractional order systems, an active feedback controller is designed to achieve the complete synchronization of power system.Finally, the characteristics of chaos and multi-stability of the integer four-order power system are studied through numerical simulations. The importance of excitation segment is also explained, and the impacts of mechanical power, damping factor and exciting gain of the time-delayed power system are discussed in detail. The co-existing attractors of periodic and chaotic are observed with different initial conditions. To eliminate these phenomena, a nonlinear feedback controller is designed to achieve the synchronization of drive system and response system, which will ensure the stable operation of system.