Stability criterion for the maximum clearing time of a DFIG: An equal area criterion's equivalent for induction generators

Stability is a primordial concern of power systems. From the generator point of view, it means that the machine must be able to attain an equilibrium state (possibly the pre-fault state) once the system is back to normal operation. For Synchronous Generators, the Equal Area Criterion (EAC) can be used to determine the maximum fault clearing time also known as critical clearing time. Such criterion is not valid for Induction Generators. In fact, only a few works aimed for a stability criterion for Doubly-Fed Induction Generators (DFIG). Since the EAC uses the power-angle profile of the synchronous machine, the work done here proposes the use of the power-slip profile of the DFIG. Using the power-slip profile of a DFIG, an analytic method for critical fault clearing time for a DFIG is developed. The analytic values calculated using the criterion are compared with values obtained through simulations showing accurate results. Hence, the method can be used as an indicator for transient stability for DFIG.