Toward a globally robust decentralized control for large-scale power systems

A robust control scheme is presented that stabilizes a nonlinear model of a power system to a very large class of disturbances that includes any disturbances causing the system to exhibit sustained oscillation. The disturbance can be anywhere in the power system. The fact that the improvement in stability is significant and system wide leads to the name globally robust control. The control is local or decentralized in the sense that the control of each generator depends only on information available at that generator, and is derived using Lyapunov's direct method. The derivation is quite general, permitting a second-order representation of the turbine/governor and any generator model. Simulation results are presented which show the effectiveness of the proposed control against instabilities of current importance including sustained oscillations following a major system disturbance such as a fault or major line outage. The control is also effective for steady-state operation.