Black-Box Impedance Identification and Modeling for Time-Domain Transient Analysis of Power Electronics-Based Energy Conversion Systems

The high penetration of power electronic converters in power systems imposes new dynamics and a wide range of challenges for system-level transient and stability assessment. The broad time scale of transient phenomena, diverse methodologies of controllers, nonlinearities, and reduced system transparency associated with power electronic converters pose new challenges to modern power systems and limit the application of physics-based modeling for transient and stability analysis. In this paper, using small-signal perturbation injection frequency scanning, the small-signal impedance/admittance- based models (I/ABMs) of the power-electronic-based subsystem are identified using the black-box impedance identification approach. The continuous time I/ABMs are then interfaced with the external system and used for the small-signal transient analysis (SSTA) and to perform time-domain simulations. The proposed approach is demonstrated on a power-electronic-based wind energy conversion system implemented in PSCAD/EMTDC and its accuracy and efficiency is shown for time-domain simulations.