SSN Asynchronous Machines (IM and DFIM with Rotor Turn Ratio) and No Minimum Parasitic Load Requirement

Abstract

This model implements 2 asynchronous machine models (wounded and DFIM) compatible with SSN and that does not require any parasitic load or snubber to be stable even in open stator conditions.

The DFIM notably has an explicit turn ratio number, that allows real secondary voltage to be applied to the winding (no ideal transformer required like in native SPS).

In this simulation, both rotor-cage and DFIM are driven near their nominal operating points. At 0.3 sec, the DFIM rotor load is short-circuited; at 0.4 sec., the DFIM is disconnected from the main grid. As seen in this SSN simulation, the DFIM disconnection as no impact on the model stability despite the fact that it has no load connected to it after 0.4 sec. Using only SPS without SSN, the same model requires a 1MW parasitic load at the DFIM stator to remain stable after 0.4 sec.

[Induction machine (IM); Renewable energy; Protection:Islanding; General:Stability]

References

C. Dufour and D. S. Nasrallah, "State-space-nodal rotating machine models with improved numerical stability " IECON 2016 conference