Abstract
It is well known that the direct method of Lyapunov is the most suitable method for on-line transient stability estimation of power systems. Several techniques have been proposed for the construction of Lyapunov functions, for this purpose. The effectiveness of these Lyapunov functions for power systems, however, has been demonstrated only on digital computer simulations, without experimental results. In fact, to utilize the Lyapunov functions for on-line transient stability estimation of actual power systems, it is necessary to measure state values and to manage system noise, operating time for actuating mechanical circuit breakers and computing time of the Lyapunov function well. Moreover, stability boundary obtained by the Lyapunov function is more or less moderate because the Lyapunov method gives only a sufficient condition. Hence, constructing superior Lyapunov function that estimates stability boundary closer to true stability boundary is needed. In this paper, a computer-controlled on-line transient stability estimation system for power systems is constructred, taking these problems into account. An extended Lyapunov function is utilized to estimate the transient stability of the power system with GOV. The experimental results show that the proposed estimation system can act satisfactorily for estimating the transient stability of the actual power system.
