A new modeling of loading margin and its sensitivities using rectangular voltage coordinates in voltage stability analysis

This paper presents new mathematical models to compute the loading margin, as well as to perform the sensitivity analysis of loading margin with respect to different electric system parameters. The innovative idea consists of evaluating the performance of these methods when the power flow equations are expressed with the voltages in rectangular coordinates. The objective is to establish a comparative process with the conventional models expressed in terms of power flow equations with the voltages in polar coordinates. IEEE test system and a South-Southeastern Brazilian network are used in the simulations.