A Synchronous Machine Model for Unbalanced Analyses

This paper presents a new unsymmetrical model of synchronous generators for power system transient stability simulations. The symmetrical component method has been used traditionally in the analysis of unbalanced faults in power system. This is mainly because the synchronous generators, which play an important role in the power system, can be easily treated by the method. However, when analyzing a system that has elements with unsymmetrical impedance, it may not be easy to use symmetrical component method. In such cases, the simulations can be easily executed by using the phase coordinate method. However, there are few papers that derive a phase coordinate model of synchronous machines. This paper analyzes synchronous generators under unsymmetrical condition in detail by using the symmetrical component method, and then it derives a model of synchronous generators for the phase coordinate method.