Adaptive fuzzy logic load frequency control of multi-area power system

• The paper proposes adaptive fuzzy load frequency controllers for power system.
• Fuzzy logic systems are used to construct the control laws.
• An auxiliary signal is used to attenuate the effects of the fuzzy approximation.
• Achievement of the LFC requirements in the presence of parameter uncertainties.
• A set of if–then fuzzy rules are not required to implement the proposed controller.

Based on indirect adaptive fuzzy control technique, a new load frequency control (LFC) scheme for multi-area power system is proposed. The power systems under study have the characterization of unknown parameters. Local load frequency controller is designed using the frequency and tie-line power deviations of each area. In the controller design, the approximation capabilities of fuzzy systems are employed to identify the unknown functions, formulate suitable adaptive control law and updating algorithms for the controller parameters. It is proved that the proposed controller ensures the boundedness of all variables of the closed-loop system and the tracking error. Moreover, in the proposed controller an auxiliary control signal is introduced to attenuate the effect of fuzzy approximation error and to mitigate the effect of external disturbance on the tracking performance. Simulation results of a three-area power system are presented to validate the effectiveness of the proposed LFC and show its superiority over a classical PID controller.