Following the massive blackout that occurred on 28 April in the Iberian Peninsula, the European Network of Transmission System Operators (ENTSO-E) announced on Friday 9 May how the joint group of experts (see EUROPE 13632/19) will investigate the causes of the blackout, and summarised the chronology of events.
ENTSO-E indicates that two periods of oscillations (variations in power and frequency) were observed in the continental European synchronous zone, half an hour before the incident. They were then mitigated by the Spanish (Red Electrica) and French (RTE) operators.
At around 12:30 CET, a series of power cuts were recorded in southern Spain (totalling around 2,200 MW). Then, the frequency decreased and tension increased in Spain and Portugal. The frequency of the electricity network on the Iberian peninsula continued to fall, reaching 48 Hz.
Automatic protection plans in Spain and Portugal were triggered and, immediately afterwards, the AC overhead lines between France and Spain were disconnected by protective devices.
At 12:33:24 CET, the Iberian electricity grid completely collapsed and the high-voltage HVDC lines between France and Spain stopped transmitting electricity, explained ENTSO-E, which also detailed the stages in the restoration process.
The group of experts led by Klaus Kaschnitz (APG, Austria) and Richard Balog (MAVIR, Hungary) will publish an analysis of the available data on the incident in a factual report. Recommendations will then be published in a final report.
To see the ENTSO-E publication, go to https://aeur.eu/f/grf (Original version in French by Pauline Denys)