Auteur Sujet: Blackout électrique en Espagne et au Portugal, le 28 avril 2025 (Lu 30463 fois)

alain_p · « **Réponse #348 le:** **Hier** à 22:23:59 »

Un peu plus tard, à 12h22, on voit apparaitre le rôle des petits sites PV de moins de 1 MW, qui passent sous le radar du gestionnaire du réseau REE, avec une perte de puissance générée de près de 700 MW, contre 154 MW seulement des sites > 1 MW . Voir p8 du rapport :

• An anomalous increase in effective demand3 of approximately 845 MW was detected across the country. Upon further analysis, this increase was traced to two distinct sources within the distributionnetwork:

○ A loss or reduction in the power output of generation facilities with capacities greater than 1 MW, which report telemetry to CECRE4, amounting to approximately 152 MW.

○ A loss or reduction in the power output from facilities with capacities below 1 MW, unobservable by REE in the distribution network, including of self-consumption, nearly 700 MW.

alain_p · « **Réponse #349 le:** **Hier** à 22:33:03 »

Il y a un encart spécial dans le rapport sur l'électronique de puissance, soulignant qu'elle a affectivement des capacités de faire varier la puissance en quelques secondes, mais qui pourrait être contre-productive, car pouvant amener à faire varier la production très rapidement en fonction des prix, et donc à compliquer très sérieusement le contrôle dynamique des tensions et fréquences.

Donc REE confirme que les sites PV peuvent accéder à des prix de marché fluctuants (peut-être surtout les gros sites ?). Voir p10 :

It is important to highlight the rate at which generation output can change within the system. New technologies based on power electronic inverters are capable of adjusting their output within a matter of seconds. While this capability is highly beneficial for the economic optimisation of individual generating plants, it is not necessarily ideal from a power system stability perspective in general.

A clear example of this is the rapid schedule changes in photovoltaic generation driven by price fluctuations in electricity markets. From an electrical standpoint, such abrupt changes in inverter - based generation introduce significant imbalances into the system, because regulation mechanisms haven´t operated yet. These imbalances must be compensated mainly through interconnections, particularly the one with France.

Severe imbalances lead to drastic shifts in power flows across the network, which in turn alter the capacitive and inductive behaviour of the grid. Consequently, system voltages can vary rapidly. This effect is further exacerbated when such generation operates under power factor control and doesn´t provide dynamic voltage control, as it limits the dynamic reactive power support that could otherwise help stabilise voltage.

alain_p · « **Réponse #350 le:** **Hier** à 22:39:08 »

Vers 12h22, pour mieux contrôler les oscillations, qui l'étaient mal par les centrales conventionnelles en service, le démarrage d'une autre centrale en Andalousie a été demandé. Mais le délai de démarrage était à 14h/ Trop tard.

Peu de temps après, alors qu'un réacteur nucléaire menaçait de se découpler du réseau, une autre demande a été faite pour le démarrage d'une centrale dans le nord. Délai : 15h. Bien trop tard là aussi.

Furthermore, considering the measures required to damp the oscillations and the resulting impact of these measures on system flexibility for voltage control and voltage variation management, a decision was made to connect additional conventional generation units compliant with Operating Procedure P.O. 7.4 — primarily in the southern region—. Start up times were requested, a CCGT plant, in Andalusia, was selected, offering a start up time of 1 hour and 30 minutes, with technical minimum scheduled for 14:00 h. However, this measure was never implemented due to the blackout

alain_p · « **Réponse #351 le:** **Hier** à 22:49:59 »

La conclusion du rapport, p16, est que la blackout n'a pas été du à un manque d'inertie du système, mais à des déconnexions en cascade de centrales renouvelables, suite à des variations de tension, qui n'auraient pas du se déconnecter, qui ont entrainé une perte de 2000 MW de puissance. Voir p16 :

Inertia :

The incident was NOT caused by a lack of system inertia. Rather, it was triggered by a voltage issue and the cascading disconnection of renewable generation plants, as previously indicated. Higher inertia would have only resulted in a slightly slower frequency decline. However, due to the massive generation loss caused by voltage instability, the system would still have been unrecoverable

Avec tous ces éléments, il est difficile de dire que les énergies renouvelables sont hors de cause dans ce blackout en Espagne, même si ce n'est pas complétement direct...

alain_p · « **Réponse #352 le:** **Hier** à 22:58:01 »

Voici d'ailleurs le résumé de la chaine d'incidents que fait REE qui a conduit au blackout. Les centrales conventionnelles ont peut-être failli à contrôler les variations de fréquence/tension, à voir, mais ce ne sont pas elles qui se sont déconnectées les premières. La perte en cascade de 15 GW en quelques secondes provient bien des centrales EnR.

Rq : RCW : Reewable, Cogeneration and Waste.
Tripping : délestage.

Events in the system :

As it was said at the beginning of the report, the electrical system is operated to withstand an N-1 contingency, and in some cases even N-2. For a major incident that results on a total blackout, multiple failures must occur within the system. In this incident, the following circumstances, based on the best available information at this time, have occurred in succession and some of them individually could be assimilated to an N-1 scenario:

1. Forced oscillation at 0.6 Hz, possibly originating in a photovoltaic power plant in the province of Badajoz, triggers system-altering protocolized actions. Shunt reactors are operated, lines are coupled due to oscillations, and schedules are modified. (N-1)

2. Natural oscillation at 0.2 Hz triggers further system-altering protocolized actions. Shunt reactors are operated, lines are coupled due to oscillations, and schedules are adjusted. (N-2).

3. Generation under P.O. 7.4 does not absorb the required reactive power. (N-3).

4. Variations in RCW generation during active power regulation affect voltage control and many of them don´t fulfil their obligations. (N-4).

5. The conventional generation requested after the oscillations was not connected.

6. Generation loss in distribution: P < 1 MW and self-consumption of 435 MW before 12:32:57 (N-5).

7. Inappropriate tripping of a generation transformer in Granada (N-6).

8. Inappropriate tripping of solar thermal generation (Badajoz) and tripping of photovoltaic (Badajoz) without point-of-interconnection data from transmission network (N-7).

9. Inappropriate tripping of a photovoltaic power plant connected also in the province of Badajoz but in a different transmission substation (N-8).

10. Tripping of three wind farms (Segovia) without point-of-interconnection data from transmission network.

11. Tripping of one wind farm and a PV plant located at the province of Huelva, without point-of-interconnection data from transmission network.

12. Inappropriate tripping of photovoltaic power plant in Seville (N-9).

13. Inappropriate tripping a PV generation located in the province of Cáceres (N-10).

14. Tripping of PV generation connected to a 220 kV substation located in the province of Badajoz, without point-of-interconnection data from transmission network.

15. Tripping of one CCGT unit located at Valencia (N-11).

16. Load shedding of pumping units and loads due to underfrequency results in increased system voltage.

17. The HVDC link operating in constant power mode continues exporting 1,000 MW to France.

18. Tripping of Nuclear Power Plant. (N-12)