ON an improved delay-dependent robust stability criterion and application to power system statbility analysis with time delays

In this paper, Lyapunov stability theory and linear matrix inequality (LMI) method are used to analyze the delay-dependent robust stability of power systems with multiple time delays. An improved delay-dependent robust stability criterion for power system with multiple time delays is presented. A proper Lyapunov functional is firstly constructed based on Lyapunov-Krasovskii theory. And, in the deduction of its derivative function along the system trajectory, some necessary slack variables are introduced so as to reduce its conservatism. Then the method is applied to the robust stability analysis for power system with time-varying delays and uncertainties. It can be found the present method is correct, effective and with less conservatism.