Applications of robustness theory to power system models

The applicability of the recently developed frequency-domain, matrix-norm robustness margins for physical systems is explored in this paper using a power system example. The power system is modeled using the damping-and synchronizing-torque framework. The robustness margins evaluated at several junctions of the power system model are shown to be useful measures of the system´s tolerance for unmodeled shaft torsional dynamics and variations in the effectiveness of power system controllers (e.g., multiterminal high-voltage dc modulators). In addition, the robustness margins are shown to be useful for comparing the robustness of alternate controller designs. This paper ends with general guidelines for applying the matrix-norm robustness margins to physical systems.