The saturated synchronous machine

WHILE the unsaturated synchronous machine is in general well understood, the effects of saturation upon its performance are still subject to discussion. Knowledge on the influence of saturation is important because of power-angle relations, steady-state stability limits, and excitation requirements. The problem of saturation may be approached in several ways. One method¹ is to determine empirical factors which modify characteristics of the unsaturated machine, the saturation factors being single average values for a group of machines. A second way² leads to the introduction of equivalent reactances which allow calculation of the effects of saturation on small load changes about an initial operating point. Third, there is the derivation³ of saturated synchronous reactances to be used in the investigation of power-angle curves and maximum power.