Re: Causes of the Gran Apagón (Spain), first oficial report

On 2025-06-19 14:42, Martin Brown wrote:

On 19/06/2025 09:04, Carlos E.R. wrote:

On 2025-06-19 06:29, Bill Sloman wrote:

On 19/06/2025 1:28 am, Martin Brown wrote:

 

It is odd that they don't explain why it failed so spectacularly quickly. The final grid collapse took 5s and then it was all over.

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The speed is perfectly explicable. If you have lots of identical controllers, all designed to turn themselves off when they see a particular situation, they are all going to turn off at once.

 That is the sort of detail that should be in the report and isn't.

And maybe it is. The actual report is many pages, not what the press published.
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A huge solar plant is being named. Well, its name has leaked.
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<https://www.eldiario.es/economia/central-fotovoltaica-origen-apagon- megaplanta-nunez-balboa-iberdrola_1_12395979.html>
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*The photovoltaic plant at the origin of the blackout is Iberdrola's Núñez de Balboa mega-plant.*
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     As confirmed by elDiario.es, it was this plant which, half an hour before the outage, when it was generating 250 MW, began to produce anomalous oscillations which Red Eléctrica has asked to investigate and attributes to ‘a malfunction of an internal control’ or ‘an internal anomaly (...) to be clarified by the owner’
  - Red Eléctrica places the start of the blackout in the ‘malfunction’ of a photovoltaic plant in Badajoz
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  The photovoltaic plant in the province of Badajoz that triggered the historic blackout on 28 April, when it caused a series of anomalous oscillations in the grid, is Iberdrola's Núñez de Balboa mega-plant. This was confirmed to elDiario.es by several sources familiar with the confidential reports of the Government's commission of experts and the system operator, Red Eléctrica, which asked to investigate the ‘malfunctioning’ of this installation, one of the largest solar parks in the country.

 Now we are getting somewhere...
Thank heavens for unauthorised leaks in corrupt political administrations.

This is not corruption. Secrets can not be maintained from the press when there are hundreds of people having the data.
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As REE's Director of Operations, Concha Sánchez, explained at a press conference on Wednesday, this ‘very significant’ fluctuation lasted almost five minutes and required “immediate” action as it was a ‘dangerous’ situation: the way in which the interconnection with France operates had to be changed, as it stopped operating on alternating current and switched to fixed set-point, and the grid meshing was increased, which complicated voltage control.

 "stopped operating on AC" does that mean it can switch to DC operation to allow Spain to freewheel its grid frequency?
 If it was operating in "DC mode" why did it disconnect?

I'm not clear in their actual meaning.
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‘During this period, some calls are reported by agents to the System Operator about the oscillations’ and ‘a sudden drop in the damping of the system is detected’, which ‘becomes more vulnerable’. The same oscillation is reproduced at 12.16 pm. One minute earlier, the Núñez de Balboa plant had ‘changed its production’ from the aforementioned 250 MW to 350 MW.

 Did some of the classical turbine generator systems drop off grid prematurely to save themselves from the frequency going out of bounds? That could partially explain the loss of damping (or was there almost no spinning reserve making power at the peak of solar PV output).

Yes.

 

According to the REE report, ‘no fluctuations were observed in the plant's active power’, but ‘in reactive power’, which is needed to operate the electricity grids. This second oscillation of Núñez de Balboa comes shortly before another less atypical one originating in the centre of Europe at 12.19 pm, a prelude to the succession of overvoltages that will begin at 12.22 pm, which the system will not be able to absorb and will end up leading to the blackout.

 The fluctuation "originating" in the "centre of Europe" sounds more like a reaction to Spain injecting fluctuations into the continental grid.

Which is impossible if the connection was DC. So it can not be DC but some other meaning.
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"Before, during and after
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When asked by elDiario.es, Iberdrola does not comment on this matter. On Wednesday, sources from the electricity company told Europa Press that its behaviour was ‘impeccable’, in contrast to the ‘reckless and negligent’ management of REE, and expressed their “astonishment” at the statements made by those responsible for Redeia, ‘who seem to confuse the consequences of the blackout with its causes’.

 It will become a finger pointing game and only the fat slimly lawyers defending their clients will win in the end. Decade long legal battle...
 

While the groundwork is being prepared to determine who is responsible for the blackout, with a view to the millions in compensation that will have to be paid to those affected in the future, Iberdrola has been pointing the finger at REE, as the electricity system operator, as being responsible for the incident for weeks.

 They have had enough warnings that something like this would happen if they cut their spinning reserves right to the bone.

Notice that Iberdrola has generation of all kinds, from ancient turbines to state of the art solar.
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The government has also pointed out (this analysis is shared by REE) that this reserve market did not work as it should: the three nuclear reactors and the six combined cycle gas plants that were supposed to operate under technical restrictions (a mechanism with which electricity companies pocket billions every year) ‘were not regulating voltage’ as they should when these surges began. One gas plant in southern Spain stands out as doing the opposite of what it should have done: it injected reactive power instead of absorbing it.

 If that is true then they should be prosecuted for it. They helped to bring down the grid. It doesn't bode well when the investigators have their hands tied by government and the energy companies to anonymise who was guilty of what! Better to pretend it was multifactorial and completely unforeseeable than try to find and fix the actual root cause.

The names are not published now, they will be named later, at another stage.
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Cheers, Carlos.