Look-ahead based method for selection of preventive control for voltage stability analysis

In recent years, the analysis of voltage stability has become crucial for the proper operation of electrical power systems, especially when it comes to large systems. The need for effective voltage control strategies have been brought to evidence in a considerable number of studies, as power system loads are located farther away from power plants and losses have tended to increase due to heavier power flows over long distance transmission loads. A new methodology for selection of the most effective controls to prevent voltage instability in electrical power systems is developed in this paper. The proposed methodology is fast and suitable for real time operation. It is based on a sensitivity analysis of both a maximum loadability estimate (which is obtained via Look-Ahead method) and the load flow solution with respect to the selected controls. The methodology was successfully tested in two systems: the reduced equivalent model of the southern Brazilian system (represented by a 33-bus model) and the south-southeast Brazilian interconnection (represented by a 65-bus model).