The European Network of Electricity Transportation Network Managers (ETSO-E) has advanced this Friday a preliminary report indicating that the blackout last Monday, April 28 was due to a “complex sequence of events” and details that two periods of tension and frequency oscillations were recorded in the European continental electrical system during the half hour prior to the incident.
The Community Association, which has been responsible for preparing an independent European investigation into the energy incident, has reported late this Friday in a statement that in the half an hour before the blackout, which occurred at 12.33 hours, two oscillations were recorded in terms of power and frequency between 12.03 and 12.07 and between 12.19 and 12.21.
“The transport network managers of Spain (Red Eléctrica) and France (RTE) took measures to mitigate these oscillations. At the time of the incident, there were no oscillations and the variables of the electrical system were within the normal operation range,” explained Entso-E, which has found that Spain was exporting until then 1,000 megawatts (MW) to France, 2,000 MW A Portugal and 800 MW to Morocco.
The agency has indicated that the event began at 12:32:57 and that, in the subsequent 20 seconds, a “series of different generation interruptions” were scored in southern Spain worth about 2,200 MW.
“In Portugal and France, no generation interruptions were observed. As a consequence of these incidents, the frequency decreased and an increase in tension in Spain and Portugal is observed,” he collects in this preliminary report.
Already between 12:33:18 and 12:33:21, the frequency in the Peninsula continued to fall to 48 Hercios, which activated contingency plans of both Spain and Portugal. In turn, alternating current networks between France and Spain were successfully disconnected in the face of the loss of synchronicity.
Thus, at 12:33:24 the “complete collapse of the Iberian electrical system” and high voltage cables between France and Spain materialized they also stopped transmitting energy.
Reset of the network in record time
Entso-E stressed that at 12.44, just 10 minutes after the incident, a first line of 400 kV between western Spain and France was reactivated again, and that, 20 minutes later, the interconnection between Morocco and Spain was already operational.
From the beginning of the restoration to approximately 13.30, several Spanish hydroelectric plants with “black start capacity” were launched to initiate the restoration of the system. At 1:35 p.m., the connection on the eastern flank of the Franco-Spanish border was active again. Also, at 16.11 and 17.26 Spanish peninsular time, the two electric plants of Portugal with starting capacity in Isla managed to restart after the “unsuccessful previous attempts.”
Then, the first 220 kV line between Spain and Portugal again received energy at 18.36 hours, accelerating the restoration of the Portuguese system. In addition, at 9:35 p.m., it was the turn of the 400 kV connection that exists in the south of both countries. Finally, the total recovery of the transmission system was completed in Portugal at 00.22 hours on April 29 and in Spain about 04.00 of the same day.
The Ministry considers the analysis a “good news”
For its part, the Ministry for Ecological Transition and the Demographic Challenge has considered a “good news” that has advanced in the analysis of the causes of the blackout and that initial estimates of the generation losses have been provided. In addition, “he has greeted” the designation of the panel of experts who will direct the independent investigation of Entso-E.
“Entso-E has moved that the causes of the crisis are complex and informs of two periods of tension and frequency oscillations in European electrical systems during the half hour prior to the incident, which stabilize the TSO [siglas, en inglés, de Transmission System Operator (Operador del Sistema de Transporte)] of Spain and France, ”sources from the Ministry have indicated to Europa Press.
Likewise, the department led by Sara Aagesen has reported that the Committee for the analysis of the crisis, whose working groups will continue working this weekend, will meet again next Monday. “The Committee will analyze all the available elements and continue working with all the operators to know with certainty the origin of the incident,” they added.
Source: www.eldiario.es
