Modelling saturation of laminated salient-pole synchronous machines

Most equivalent circuit models for the generalised synchronous machine have either neglected saturation or used only one saturable reactance as a function of one or more of the machine variables. The variation of such a saturated reactance has been obtained in most cases experimentally. The paper adopts an accurate model for the laminated salient-pole alternator which represents the damper winding properly. The equivalent circuit reactances, which are liable to saturation, are determined. Also, saturation factors relating the saturated to the unsaturated parameters are presented as functions of the machine design particulars. A digital computer program has been developed to simulate the mathematical model. Predicted steady-state performance with zero and 0.8 power factor loads and transient 3-phase symmetrical short-circuit performance are compared with measured results. The comparison confirms that the suggested saturated model is capable of predicting the machine performance with good accuracy.