Global control of stressed power systems

A multilevel control scheme that is capable of system control over wide ranges of operating conditions for nonlinear systems is proposed. The first control level confines the system operation to some reference segments in its state space. Each reference segment is further subdivided using bifurcation analysis for establishing the bounds on regions of the state space of the system with different control requirements. The principles of global control lead to a hierarchical control structure which combines regional (linear or nonlinear) controllers smoothly. The scheme is illustrated for control of a power system known to have complex dynamical behavior for a wide range of loading levels.