Analysis of the 2023 Iberian Blackout: Grid Collapse and Recovery

On April 28, 2023, a severe blackout affected 50 million people across Spain and Portugal, extending to southern France, with a 23-hour outage. The event began with forced oscillations from a photovoltaic plant in Badajoz, leading to voltage fluctuations and inter-area oscillations. Despite measures like coupling transmission lines and reducing exports to France, a cascade of generator trips occurred, starting with a transformer trip in Granada. Within seconds, multiple wind farms, photovoltaic plants, and conventional generators disconnected, causing the system frequency to drop to 47.79 Hz. The interconnection with France and Morocco tripped, isolating the Iberian system. Nuclear and combined-cycle gas turbine units sequentially disconnected, leading to total collapse at 12:33:27, with voltage below 1 kV. The analysis highlights the vulnerability of modern power systems with high renewable penetration to cascading failures and underscores the need for real-time modeling, coordinated control of transmission-distribution-microgrid, and active defense strategies for extreme scenarios. Rapid recovery was enabled by renewable generation, but the incident emphasizes the importance of robust grid management and contingency planning.