S. Greene et al., SENSITIVITY OF THE LOADING MARGIN TO VOLTAGE COLLAPSE WITH RESPECT, TO ARBITRARY PARAMETERS, IEEE transactions on power systems, 12(1), 1997, pp. 262-268
Loading margin is a fundamental measure of proximity to voltage collap
se. Linear and quadratic estimates to the variation of the loading mar
gin with respect to any system parameter or control are derived. Tests
with a 118 bus system indicate that the estimates accurately predict
the quantitative effect an the loading margin of altering the system l
oading, reactive power support, wheeling, load model parameters, line
susceptance, and generator dispatch. The accuracy of the estimates ove
r a useful range and the ease of obtaining the linear estimate suggest
that this method will be of practical value in avoiding voltage colla
pse.