Robust nonlinear control for a power system with multiple machines connected to the common bus terminal

In this paper, we propose a robust design method for excitation control of a power system for the typical case where different machines are connected to the common bus terminal. In the design method, we do not need to equalize the generators. We design one controller for each specified generator independently without knowing the parameters of other generators. Thus all the problems caused by the equalization are automatically eliminated. Using only local variables at the transformer ends, we can design the controllers for each generator separately despite the nonlinearities and interconnections among different generators. A two-generator example test system is presented to illustrate the effectiveness of the proposed excitation control system. For comparison, simulation between the proposed approach and the equalization approach, and the proposed approach and PSS are given. The results show that the equalization approach is not accurate in analysis of power system transient stability, but the proposed controller can effectively enhance the system transient stability and improve the system damping.