Two-tier approach for the design of multiple power oscillation damping controllers

The effective damping of low frequency oscillations is of vital importance, especially given that today's interconnected power systems are constantly demanded to operate closer to power transfer limits over extended periods. With new possibilities in wide-area monitoring technologies, the number of signals which are available for use as feedback-stabilizing-signals for power oscillation damping controllers is large. The selection of the best actuator-signal pairing for power oscillation damping enhancement is therefore of key importance. This paper proposes a systematic procedure for the selection of feedback signals for use as feedback-stabilizing-signals, taking into account the nature of interaction among electromechanical modes damping loops. The selection criteria is based on computation of transfer function residues for critically damped modes and then use of an interaction index based on performance relative gain array to examine potential adverse control loop interactions. The approach is tested on a forty-four bus system.