Iberian blackout was caused by multiple factors, report says

By Pietro Lombardi

MADRID, March 20 (Reuters) – The massive power outage that hit the Iberian Peninsula in April last year was the result of multiple factors that ultimately led to a voltage surge and a chain of power-generation loss, a European network of electricity transmission system operators called ENTSO-E said in a report on Friday.

In the organisation’s final report into the blackout, it looked at its root causes and offered recommendations to reinforce Europe’s power grids and avoid similar incidents in the future using available solutions. The report is not meant to assign blame.

Like previous inquiries, the report confirmed preliminary findings by the organisation, pointing to a surge in voltage as the immediate cause of the April 28 outage – the first of its kind and Europe’s most significant blackout in more than two decades, which left large parts of Spain and Portugal without power for up to 16 hours.

ROOT CAUSES

The report mentioned several factors as root causes of the blackout. These included conventional power plants – thermal power plants using coal, gas and nuclear – that did not help control voltage as expected by the grid operator based on existing rules. In addition, some network components to control voltage operated manually, taking more time, and settings to disconnect equipment to protect them from a surge of voltage were not in line with existing requirements.

The report also highlighted that the Spanish grid operates at a wider range of voltage than other European countries, meaning that the margin between allowed voltage limits and those triggering disconnections was very small or non-existent.

Moreover, the management of the power links with France could have made the system behaviour worse, it said.

“The analyses above clearly indicate that the key phenomenon in the incident was the non-effectiveness of voltage control within the Spanish power system,” the report’s summary said.

MISSING DATA AND RECOMMENDATIONS

Experts couldn’t establish the reasons for some initial power-generation losses in Spain because the owners of those power plants said they lacked the required data, the report said.

The report also included some recommendations to avoid similar events in the future. These include improving monitoring of the power system and better coordination and data exchange among players in the power system.

(Reporting by Pietro Lombardi; Editing by David Latona and Thomas Derpinghaus)