The transient stability of power systems is investigated using Liapunov's direct method. Willems' method is applied to three-and four-machine power systems with the effect of damping included. The distribution of damping among the machines of a multi-machine system is studied, and optimum ratios are derived. An extension of Willems' method is used to include governor action in the system representation. Finally, the effect of flux decay on stability regions is studied using Chen's method. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

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In this thesis Liapunov's direct method is applied to transient stability study of power systems. Szego's method is applied to a second order power system in chapter two and a quadratic Liapunov function applied to the same system in chapter three. The hypervolume enclosed by the quadratic V-function is maximized. Changes in the time derivative of the quadratic V function are then made to meet the conditions of Liapunov V and V functions. Finally a maximized modified Liapunov function is constructed from a tentative quadratic function for a three-machine system. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

Lyapunov functions are applied to the power system studies. Three types of power system problems are investigated, namely, the determination of asymptotic stability regions of a nonlinear power system for fault and switching transient stability studies, the systematic optimum parameter setting of power system controllers, and the determination of linear and nonlinear optimum stabilising signals as functions of state variables for both nonlinear and linearized power systems. To investigate and construct the transient stability region of a synchronous machine connected to infinite bus through a transmission system after fault and switching, high degree Lyapunov function series generated by Zubov's method is applied. For the optimum parameter setting of a power system, a computation technique based on the method of gradient has been developed to adjust the system parameters simultaneously so as to minimise a system performance function which is evaluated from a Lyapunov function of the second degree. For the computation of the second degree Lyapunov function a method based on the concept of similarity transformation has been developed and applied so that the simultaneous solution of a large number of algebraic equations can be avoided. To determine the optimum stabilizing signals for a power system, the concept of the Lyapunov function of the optimum system is applied. To compute the Lyapunov function of the optimum nonlinear power system, a general iterative scheme and algorithm have been developed. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

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Thesis (M.S.)--University of Wisconsin--Madison, 1969. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

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