This paper presents results of a study of the Brazilian system operation in respect to voltage stability criteria. The analyses are applied using real-life data from the operation and planning. The system is divided in 4 regions: North, Northeast, South and Southeast/West Center. System stability margin is evaluated for each one of these areas. The results show that Brazilian system has stability margin much lower than the existing voltage stability criteria, limited by the Southeast/West Center region. A detailed analysis of this critical area is performed. This paper also presents the stability margin behavior during a typical weekday curve and a contingency analysis. The contingency severity is verified by using the modal analysis technique assessing each contingency impact classifying as local, area or systemic.
Voltage Stability; PV curves; Modal Analysis; Brazilian system
