Determination of critical reactive power points in power systems loadability studies

This paper proposes a methodology to analyze steady-state voltage stability from the point of view of reactive power generation limits. Two main aspects are focused: 1) the identification of the critical points of reactive power generation as the power network loadability increases; and 2) the classification of these loadability levels from the point of view of bifurcation theory. It is shown how the formulation of the power flow equations in rectangular coordinates can be exploited, particularly to deal with the reactive power generation limits in order to find limit-induced bifurcation points. Simulation results obtained with the IEEE 24-bus test system are used to illustrate the performance of the proposed methodology.