António Pedro Santos / Lusa
A group of people wait for the power to be restored in Bairro da Liberdade
The investigation concluded that the April blackout resulted from a combination of several interconnected factors. Spain did not make it easy with the data.
Almost a year after what left Portugal and Spain in the dark, the panel of experts from the European Network of Electricity Transmission Network Managers (ENTSOE) is published.
It was prepared by a panel of 49 members, including representatives from Transmission System Operators (OST), Regional Coordination Centers (CRC) and National Regulatory Authorities (ARN).
In Portugal, the data came from E-Redes and producers Akuo, Aquila, Axpo, CWPOWER, Dos Grados, EDP-Produção, EML, Energi Innovation, Engie, EXUS, Galp, Iberdrola, Powersun Solutions, Neoen, Prosolia, Vector Renewables, Voltalia, Welink and WiseEnergy.
The research concluded that the blackout resulted from a combination of several interconnected factors: oscillations, failures in voltage and reactive power control, differences in voltage regulation practices, rapid reductions in production and disconnection of generators in Spain, and unequal stabilization capabilities.
It was all these factors that led to rapid voltage increases and cascading generation disconnections.
O operating framework of conventional producers (such as thermoelectric and hydro plants) in terms of reactive energy “does not include specifications for dynamic behavior”.
O tension control drawing from small local networks does not help; “is not aligned with the needs of the system”.
As multi-production unit protection settings against overvoltage phenomena were also not aligned with the needs of the electrical system. And what happened: some of the small photovoltaic units automatically disconnected from the grid with the activation of the inverter protections; and this accentuated the network imbalances at the time of the blackout.
Overall, ENTSOE emphasizes that Spain should have better voltage control capacityregardless of the production technology, highlights the .
And the “pointing the finger” at Spain doesn’t stop there: collecting information from Spain was “more challenging” – it took more than 240 emails. “However, some data is still missingmainly in relation to stoppages in certain power generation units that occurred before the blackout, which prevented the Panel of Experts from identifying the cause of these stoppages due to the lack of failure records. The owners of these facilities cited a lack of data as the reason they were unable to provide this information to the investigation.”
This was the most serious incident and unprecedented in the European electrical system in more than 20 years, warns the document.
Para o futuro, be DONE recommends strengthen operational practices, improve monitoring of system behavior and closer coordination and greater data exchange between electrical system participants. And it is necessary to adapt regulatory frameworks to keep up with the evolving nature of the electrical system.
REN – Redes Energéticas Nacionais has already reacted: this report “confirms what REN said from the beginning: the crisis originated in Spain and its spread to the National Electric System (SEN) was inevitable”.
