Stability analysis of networked micro-grid load frequency control system

Abstract

In this paper, the problem of ascertaining delay-dependent stability of networked micro-grid load frequency control systems with time-varying and time-invariant delays has been addressed using Lyapunov approach. In the networked micro-grid control system, it is observed that transfer of incremental frequency variable (feedback variable—an indication of the in-balance between the generation and the demand) through open communication links to effect closed-loop load frequency control introduces time-delays in the feedback path. The feedback delays are generally time-varying in nature, and invariably, they exert a detrimental effect to the overall performance of the closed-loop system paving way to instability. In this paper, using the classical Lyapunov–Krasovskii functional approach combined with appropriate inequalities, less conservative delay-dependent stability criteria are presented in linear matrix inequality (LMI) framework for networked micro-grid control system with time-varying and time-invariant delays. In the sequel, the presented results are validated on a standard benchmark system.