A global group of preventive controls for critical contingencies in the context of voltage stability

A new methodology for grouping and selecting the most effective controls to prevent voltage instability in electrical power systems with multiple critical contingencies is developed in this paper. This methodology is based on a sensitivity analysis of the maximum loadability point with respect to voltage controls. Considering not only the effectiveness of the control elements but also their availability, the methodology design a set of controllers to eliminate all critical contingencies. The methodology is fast and suitable for on-line assessment of preventive control. The methodology was successfully tested in a reduced south-southeast Brazilian system composed of 107 buses.