Linear and Uniform Swing Dynamics

The share of power converter-based renewable generation is steadily increasing at the expense of rotating inertia. Virtual synchronous machines are deemed to ensure system stability, however, there are no widely accepted criteria for the design of their controllers. In converter-dominated power systems, one of the main challenges will be to analyze power angle stability, because of the large number (and possibly divergent design) of converters. Converters, however, also offer the possibility to shape system dynamics in away that was impossible with synchronous machines. In this paper, we elaborate the new concept of linearized and uniform swing dynamics. This allows the linearization of the nonlinear swing behavior over almost the entire power range, thereby extending the validity of the small-signal stability analysis techniques for larger disturbances. By properly choosing the controller parameters, the dynamics of the large number of converters expected in the system can be made unified and predictable.