A MINIMAL-REALIZATION APPROACH TO REDUCED-ORDER MODELING AND MODAL-ANALYSIS FOR POWER-SYSTEM RESPONSE SIGNALS

The present paper reports on a numerical scheme for compressing in par ametric form small signal electromechanical responses of multimachine power systems, originating from transient stability programs (TSP) or actual field testing. The result is achieved by using a multi-input mu lti-ouput (MIMO) minimal realization algorithm based on singular value decomposition (SVD), which can explicitly take into account the criti cal impact of the input interactions. The resulting parametric model i s a reduced order representation of the underlying complex system, yet it is optimal (in the least-squares sense). Besides compact storage o f damping information, the balanced state-space realization as such re tains the principal components of the response signals, and could thus be useful for the tuning of static Var systems (SVS) and power system stabilizers (PSS). When it is transformed in the modal space, the mod el also provides insight into modal interaction mechanisms. Several ex amples are included for illustration purposes and other applications a nd improvements are also discussed.