Abstract: Traditionally, frequency regulation in power system is achieved by balancing generation and demand through load following, i.e., spinning reserve and non-spinning reserves. In such cases, energy storage and responsive loads show great promise for balancing generation and demand. This paper investigates delay-dependent stability of load frequency control (LFC) emphasizing on multi-area and deregulated environment. Based on lyapnov theory and the linear matrix inequality technique, a new stability criterion is proposed to improve calculation accuracy and to reduce computation time, which makes it be suitable for handling with multi-area LFC schemes. The interaction of delay margins between delay margins and control gains are investigated in details. Case studies are carried out based on two-area traditional, two-area and three-area deregulated LFC schemes, all equipped with PID-type controllers, respectively. The main objective of this paper is to proposing an improved stability criterion with higher accuracy and less computation time to determine delay margins of multi-area LFC schemes and to reveal the interaction effects between different areas. The presented principles and controls have been verified by MATLAB simulation techniques.
Keywords: Delay margin, deregulated environment, feedback signals, Communication network, LFC, Propagation delay, Multi area.