Direct calculation of reactive power limit points

A knowledge of points where sources of reactive power encounter limits is useful in determining the vulnerability of a power system to voltage collapse. This paper proposes a predictor/corrector technique which quickly and robustly finds such points. The predictor is based on sensitivity ideas, whilst the corrector is a slight modification of the standard power flow problem. It is shown that a knowledge of limit points can provide a fast estimate of the point of collapse of a power system, and that it can improve the usefulness of some common voltage collapse indices.