Regions of transient stability for power systems involving saliency using the Popov criterion

The Popov criterion has previously been applied to power systems involving round-rotor machines. Here the method is exploited to obtain regions of transient stability for a single-machine system taking into account the effects of saliency. The generalised Popov criterion, which applies to systems with more than one nonlinearity, is used. The resulting regions of stability are shown to approximate closely the exact regions, and those previously obtained using the method of Zubov.