Robust Wide-Area TS Fuzzy Output Feedback Controller for Enhancement of Stability in Multimachine Power System

This paper presents a systematic procedure for designing a wide-area centralized Takagi-Sugeno fuzzy controller to improve the angular stability of a multimachine power system. The proposed fuzzy controller is robust and designed by satisfying certain linear matrix inequality conditions, to stabilize the system at multiple operating points. The bilinear matrix inequality problem, encountered in Lyapunov-based stability criterion, has been converted into a convex optimization problem to eliminate iterative solution. The input-output control signals are selected in the proposed control scheme by defining joint model controllability and observability index applying geometric approach. The proposed wide-area control scheme employs a global signal from the centralized controller to damp out the interarea mode of oscillations, apart from the local controllers, which are assumed to be present to damp out the local mode of oscillations. The proposed control scheme has been implemented on three test systems. The effectiveness of the proposed control scheme has been compared with a robust wide area control scheme based on mixed H₂/H_∞ output feedback synthesis and with a conventional power system stabilizer control scheme.