Multi machine power system excitation control design via theories of feedback linearization control and nonlinear robust control

The dynamics of a large-scale power system are both nonlinear and interconn ected. The equilibrium of such a system is typically unknown and uncertain, and the controllers within are also subject to physical limitations. In th is paper, a new application of nonlinear robust control is presented for po wer system control design. rt is assumed that the controllers are designed as a part of generator excitation system design. First, a customized exact feedback linearization scheme is developed for the power system under inves tigation. This new linearization scheme allows one to transform the power s ystem with a single-axis system model into a linear uncertain system with a n unknown equilibrium. Based on the latest development of nonlinear robust control theory, a novel control design is then applied to stabilize the res ulting linearized uncertain system. Finally, a nonlinear decentralized exci tation control is obtained by the inverse transformation. Compared with exi sting control schemes, the proposed control is free from such common defici encies of power system nonlinear controllers as network dependence and equi librium dependence. Detailed stability analysis and engineering judgment in the control design are provided. The results of simulation studies are pre sented.