Saturation Representation in Synchronous Machine Models

This paper discusses the various approaches of representing saturation in the steady–state, two–axis (direct- and quadrature–axis) frame models of synchronous machines. In particular, the important role of the magnetic coupling between the direct-and quadrature axis (cross-magnetizing phenomenon), which is commonly neglected, is demonstrated. A new model and modified active and reactive power/load angle relationships, in which the effect of the cross-magnetizing phenomenon is included, are presented. Experimental verification of the accuracy of this model and these relationships and the importance of the inclusion of the cross-magnetizing effect in them are also reported in the paper.