Analysis And Control Of Chaos In Power Systems

Chaotic oscillation in a power system has a harmful effect on the large scale interconnected power grid. Affected by the external factors and the character of the system itself, especially for new energy sources and distributed generation having been increasingly introduced to the power grid, which is an added uncertainty that would seriously threaten the secure and stable operation of power system. In this context, the research approach of this thesis begins from the modeling of the system of different orders, and then explores the problems of chaos mechanism and chaos control of integral order and fractional order chaotic systems, which helps the power system approve its efficiency and reliability.Firstly, this paper analyses the basic dynamic propertites of the interconnected power system under the disturbances of periodic load and electromagnetic power via bifurcation diagrams. And then studies the problem of chao control for the system with uncertainties, from the Radial Basis Function neural network and sliding mode variable structure control, the adaptive controller is designed to realize system identification and stabilize chaos to the target orbit, which inhibits the high frequency shaking. Secondly, many actual systems generally are featured as obvious dynamic behaviors of fractional order, therefore the chaos control problem of power systrm is extended to the fractional order case. The sensitivity to internal time-variable dynamics and external disturbances is discussed, and then prove that the uncertain fractional-order chaotic system can be asymptotically stable via a no-chattering sliding mode control strategy. Finally, consider the influence of mechanical output power on the power system, a new four-order system model is remodeled under two parameters. The sensitivity to the two system paramenters is investigated through phase plane, bifurcation diagram, Poincare mapping, the largest Lyapunov exponent spectrum and the correlation dimension, the stability of the equilibria is also discussed. Meanwhile, based on the finite-time stability theory, two control strategies are presented to control chaos to the nonzero equilibrium point. Numerical simulations demonstrate the effectiveness of the control methods.