Identifying groups of preventive controls for a set of critical contingencies in the context of voltage stability

A new methodology for grouping and selecting the most effective controls for a group of critical contingencies to prevent voltage instability in electrical power systems is developed in this paper. This methodology is based on a sensitivity analysis of the maximum loadability point with respect to voltage controls and on a hierarchical clustering analysis. 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.

I. Introduction

The occurrence of recent blackouts, with large impact in the system, associated with voltage stability problems justifies the necessity of developing Voltage Stability Analysis (VSA) tools to assess the security of Electrical Power Systems (EPS), specially in large power systems, on real time.