Stability analysis of damping compensated generator-excitation control system with time-varying delays

Abstract

In this paper, a simplified analysis procedure is presented to ascertain delay-dependent stability of a typical damping compensated closed-loop generator-excitation control system operated in a smart grid environment. In closed-loop control of dynamic systems, it is inferred that the use of smart grid technology encompassing complex sensor/measurement circuits, signal conditioning systems, and data transfer through open communication links as feedback loops introduces time-delays in the feedback path. These delays are time-varying in nature, and invariably they exert a destabilising effect to the overall performance of the closed-loop system. Using Lyapunov-Krasovskii functional approach combined with appropriate inequalities, a less conservative analysis is presented in this paper to assess delay-dependent stability of the generator-excitation control system under study. The derived stability criterion is expressed as a set of solvable linear matrix inequality (LMI) conditions so that they can be solved readily using standard numerical packages. Using a standard bench-mark system, the proposed analysis is validated through simulation studies.