Stability analysis of H∞H∞ load frequency control power systems with energy storage and interval time‐varying delays

This paper focuses on the stability of load frequency control (LFC) power systems with energy storage and interval time‐varying delays. Initially, a unified LFC model with energy storage systems is designed, from which is formulated as a time delay system to account for load disturbances. Secondly, to ensure stability and performance, an augmented Lyapunov–Krasovskii functional with system variables and time delay information is constructed. Additionally, an improved method is utilized to convert stability criteria into convex linear matrix inequalities via a negative definite inequality equivalence transformation lemma. Using Lyapunov stability theory, delay‐dependent stability criteria are derived. Eventually, to illustrate the practicability of the proposed approach, numerical examples in both isolated and interconnected power systems are provided.