Controlling unstable equilibrium point theory for stability assessment of two-time scale power system models

This paper presents the foundations of the controlling unstable equilibrium point (CUEP) theory for stability assessment of two-time-scale power system models. A conceptual two-time-scale algorithm to calculate the CUEP is provided. Taking into account the time scale features of power systems in the CUEP theory has several advantages from both a numerical and analytical point of view. Numerically, the two-time scale algorithm to calculate the CUEP is faster and more robust when compared to the traditional BCU algorithm. Analytically, we gain more insight into power system dynamics and obtain less conservative estimates of stability region and critical clearing time.