Magnetising-field saturation and dynamic behaviour of induction machines. Part 2: Stability limits of a voltage-fed induction motor and of a self-excited induction generator

In Part 1 of the paper, an improved induction-machine model was derived, making more accurate allowances for the magnetising field saturation. This model yields satisfactory results, as proved experimentally. In this Part, two interesting applications of this saturated model are discussed. The first application deals with the stability behaviour of the voltage-fed induction motor. The stability region in the parameter space is shown to be much larger when calculated by means of the saturated model. This result competely agrees with experience. The second application deals with the self-excited induction generator. The necessity to use the improved model for the prediction of the dynamic behaviour is pointed out, because the classical model leads to unrealistic predictions; moreover, only the improved model allows the minimum flux level for which self-excitation still may occur to be determined. Also, the theoretically predicted stability limit is shown to agree with experiment.