Two-time scale integrated simulation with automatic transition via dot products

This paper presents an integrated approach for transient and long-term stability simulations aiming its application for dynamic security assessment. Full time-domain and quasi steady-state analyses are integrated into a single simulation tool, providing short and long-term perspectives simultaneously. The novelty of this work regards the transition from full time-domain simulation to QSS technique (fast simulation). This is performed automatically using energy function based dot products. The dot products are used as an early termination technique as their behavior during the simulation will indicate if the system is stable or unstable. Moreover, in order to achieve a smooth transition between full and fast simulation, an enhanced version of the QSS simulation that do not eliminate any state variable from the original formulation is employed. A framework for power system analyses based on object oriented modeling was used to implement and test the proposed methodology. Preliminary results are presented and show good potential of the integrated approach.