Practical model reduction techniques for power systems

Four relatively recent techniques for model reduction (balanced, weighted balanced, optimal Hänkel and weighted optimal Hänkel) are reviewed. The usefulness of these techniques for obtaining reduced-order models of power systems for dynamic control purposes, their effectiveness, and the merits of the simplified models are illustrated on a single-machine infinite-bus system. The methods are evaluated on the basis of L_α errors, transient responses, and steady-state errors. The superiority of the frequency-weighting methods is clearly demonstrated.