Adequacy of Reduced-Order DFIG Models for Dynamic Stability Assessment

This paper investigates the adequacy of synthesizing reduced-order models of the doubly fed induction generator-based wind turbine generator (DFIG-WTG) for dynamic stability assessment. In this work, four different reduced-order models have been designed by disaggregating the dynamics of a full-order DFIG-WTG model (having sixteen states) into distinct timescales. The full-order DFIG-WTG model has been considered as the reference system for validating the proposed reduced-order models and then for studying their adequacy for dynamic stability. To perform the proposed adequacy analysis of the reduced-order models, some performance metrics have been considered, such as dynamic response using MATLAB time domain simulations, transient stability margin or the critical clearing time, computation time, trajectory sensitivity analysis of states, and values of different PI controller gains. All these measures have been tested under changes in operating conditions for each model. Further, small signal analysis have also been presented to comment on the ability of the different reduced-order models to capture the relevant dynamics of the full-order DFIG-WTG system. The presented adequacy analysis with the considered metrics is capable of identifying the most suitable reduced-order model (ROM) for conducting different studies on the DFIG-WTG system under particular operating scenarios.