Comparison of different methods for input/output signal selection for wide area power system control

The paper compares three different methods for selection of input/output signals to a multi input multi output wide area controller for the improvement of damping of critical electromechanical modes in the system. The first method is based on the controllability and observability factor analysis. The second method is based on the Sequential Orthogonalization (SO) algorithm. The third and final method combines coherency identification technique with the controllability and observability factor analysis. The methods are illustrated on the New England test system. The effectiveness of the wide area controller, based on input/output signals selected by different methods, in damping critical electromechanical modes in the system is assessed using both, small disturbance and transient stability analysis.