Modeling of Smart Transformers for Power System Transient Stability Analysis

The smart transformer (ST) has been proposed to enable bidirectional power flows among the several subsystems that compose the smart grid. For an accurate and efficient analysis of the power system dynamic response, a proper ST model must be developed. Starting from the detailed ST model, this article proposes reduced-order models according to the time scale of the ST dynamics and the simulation objective. The proposed models are classified based on the level of complexity and dynamic order, and are compared by means of relevant scenarios, namely, fault (rotor angle stability analysis), dc power exchange (power management), and system contingencies (voltage and frequency stability analysis). Finally, case studies based on the IEEE 39-bus system discuss the features and adequateness of the proposed models in a scenario of an interconnected grid with multiple STs.