On April 28, 2025, the Spanish and Portuguese power grids disconnected from continental Europe. This paper analyzes the system's dynamic behavior before the event: local and inter-area oscillations, tie-line stress, and examines Spain’s post-blackout generation strategy. The findings reveal the stable operation of renewable generations after the blackout and the importance of the grid-forming control. Recommendations include power system stabilitzer (PSS) for renewable generations and enhanced blackstart planning.
Cai et al. (Sun,) studied this question.