In total, three incidents have now been discovered during the investigation into the sudden power outage, says Spain's third vice prime minister Sara Aagesen to TV company TVE.
The two could be successfully handled by the system, according to Aagesen - but the third could not be stopped.
As a result, the blackout was a reality. The outage resulted in almost the entire Iberian Peninsula being without power for over ten hours. Tens of thousands of people were stranded on trains, subway cars, and in elevators, and at least seven people died.
Spain and Portugal have previously ruled out that the power outage was caused by a cyberattack.
