COORDINATED APPLICATION OF STABILIZERS IN MULTIMACHINE POWER SYSTEMS.

The damping characteristics of synchronous machine electromechanical oscillations are a function of system structures, operating conditions and control effects. Poor or even negative damping of machine swing modes can easily occur in widespread interconnected systems with significant power transfer across long distances. This paper addresses the problem of the most effective selection of generating units to be equipped with excitation system stabilizers in multimachine systems which exhibit dynamic instability and poor damping of several inter-machine modes of oscillation. Practical means have been developed using eigenvalue analysis techniques to guide the selection process. The linear state space matrix is derived directly from perturbation of the states of a large scale power system dynamic simulation and a subset of this matrix is used to yield the sensitivity of damping ratios of eigenvalues to stabilization measures of individual machines.