ROBUST DECENTRALIZED NONLINEAR CONTROLLER-DESIGN FOR MULTIMACHINE POWER-SYSTEMS

In this paper, a robust decentralized excitation control scheme is pro posed for multimachine power system transient stability enhancement. F irst, a direct feedback linearization (DFL) compensator through the ex citation loop is designed to eliminate the nonlinearities and intercon nections of the multimachine power system. Then, a robust decentralize d controller is proposed to guarantee the asymptotic stability of the DFL compensated system considering the effects of plant parametric unc ertainties and remaining nonlinear interconnections. The design proced ure for an n-machine power system involves in solving n Riccati equati ons. In the design of the robust nonlinear decentralized controller, o nly the bounds of generator parameters need to be known, but not the t ransmission network parameters, system operating points or the fault l ocations. Since the proposed robust nonlinear decentralized controller can guarantee the stability of the large scale power system within th e whole operating region for all admissible parameters, transient stab ility of the overall system can be greatly enhanced. The design proced ure is tested on a three-machine example power system. Simulation resu lts show that the proposed control scheme can greatly enhance the tran sient stability of the system regardless of the network parameters, op erating points and fault locations. (C) 1997 Elsevier Science Ltd.