Two periods of oscillation recorded on European power grid before power outage

The European power grid registered two periods of power and frequency oscillations, between 12:02 pm and 12:07 pm and between 12:19 pm and 12:211 pm, during the half-hour that led up to the mass power outage that left Spain and Portugal without electricity for several hours on April 28.

According to the European Network of Transmission System Operators for Electricity (ENTSO-e), the oscillations were observed in the synchronous area of continental Europe, and both the Spanish national grid operator Red Eléctrica as well as France’s RTE took measures to mitigate them.

In a statement, ENTSO-e explains that it has compiled data and a timeline of the events of April 28, until the power outage hit the Iberian Peninsula at 12:33 pm.

The timeline shows that the system “completely collapsed” and that the high-voltage lines between France and Spain stopped working. It also showed that the system was not restored fully until 4 am on April 29.

ENTSO-e further states that the power outage was the result of a “complex sequence of events,” but also stresses that the information released so far remains subject to the findings of a “detailed” investigation.

This investigation has just begun and will be conducted by a group of experts, including Red Eléctrica’s David Alvira, and led by Klaus Kaschnitz and Richard Balog, according to ENTSO-e.

The investigation will be divided into two phases: first, the experts will collect and analyze all the available data, and then,  they will make recommendations to help prevent similar incidents in the future.