Nonlinear output stabilization control for multimachine power systems

In this paper, a robust decentralized nonlinear control scheme is proposed for multimachine power system stability enhancement. The nonlinear controller consists of a novel dynamic direct feedback linearization (DFL) compensator through the excitation loop to cancel the nonlinearities and interactions among generators and a robust feedback controller to guarantee the asymptotic stability of the DFL compensated system considering the effects of dynamic output feedback and plant parametric uncertainties. The decentralized controller for each generator in the multimachine system is obtained by solving an algebraic Riccati equation. The nonlinear controller can guarantee the stability of the multimachine nonlinear power system within a whole operating region for all admissible parameters. The design procedure is tested on a three-machine power system. Simulation results show that the proposed control scheme can greatly enhance the stability of the system, regardless of the network parameters, operating points, and fault locations.