Iberien Peninsular Blackout

Many sources in the last 24 hours quoting a Spanish government report, e.g. this from Reuters, but no link to the actual government report.  Has anyone found this?

Paul Adkins

PDF

The official communique is here.  "Se presenta el informe del Comité de análisis de la crisis eléctrica del 28 de abril"

google translate summary and conclusions

In short, there was a lack of voltage
 control resources, either because they 
were not sufficiently scheduled, or because 
those that were scheduled did not provide them 
adequately, or because of a combination of both, 
but not because they were lacking in the country; 
there was more than enough generating capacity
 to respond.

MAIN RECOMMENDATIONS
In light of the conclusions obtained
 from the analysis, the Committee 
proposes a series of actions to 
prevent a recurrence of this type
 of incident. These include 
strengthening supervision and 
verification of compliance with 
obligations by all stakeholders 
in the electrical system, as well 
as technical measures to strengthen
 voltage control capabilities 
and protect against fluctuations 
in the system. Key to this is 
the implementation of OP 7.4, in 
the hands of the National Commission
 of Markets and Competition (CNMC).
 This will allow asynchronous 
installations to apply power 
electronics solutions to manage
 voltage variations and may 
contribute to cost savings with 
the introduction of more competitive
 technologies. Furthermore, it 
proposes increasing demand and the 
flexibility of the electrical system.
 All of this will be supported by 
the 2025-2030 Electricity 
Planning—which will prioritize 
industrial consumption—an increase
 in storage capacity, and a review
 of the regulation of adjustment 
services and the system's technical 
restrictions.

Thanks, this makes interesting reading.

I hope this is not a stupid question: Why would disconnecting generating plant from the grid cause the voltage to increase?  

Paul Adkins

presumably because that generator is actually motoring- or acting as an inertial drag on the system.If you have light loads and embedded generation the traditional slope of the voltage drop from generator to load can be reversed  and in a sense the tail tries to wag the dog.

Its not a condition you want to persist for extended periods however.

Mike

The issue seems to be about managing reactive power flows. If the service providers who were absorbing VArs trip off, then the remaining excess VArs will raise the voltage across the system

- yes no significant real power is generated, rather absorbed at one point in the mains cycle and pushed out in another, but in effect providing a giant power factor correction at grid level.

I'm also not sure if this includes waveform quality correction here - I suspect the inverter derived wave-forms are a lot dirtier in terms of square edges  than sine-waves from rotating magnets.

Certainly both the line- and self- commutating thyristor based DC link stations generate some pretty unpleasantly rectangular current bursts and rely on other grid elements to spread what are in effect  current impulses more uniformly across the cycle. In the hopelessly simplified circuit below the upper wave-forms near the in and out terminals illustrate this. (The pale grey sine is voltage and the darker bumpy thing represents the general form of the current into or out of the grid) 

Instructions always say that a low impedance grid is needed to keep the voltage waveform from becoming more like that of the current. (sometimes expressed as harmonic content vs supply impedance)
Removing e.g. the French AC connection and leaving a large DC station on would perhaps  have been problematic in this way
M

- yes no significant real power is generated, rather absorbed at one point in the mains cycle and pushed out in another, but in effect providing a giant power factor correction at grid level.

I'm also not sure if this includes waveform quality correction here - I suspect the inverter derived wave-forms are a lot dirtier in terms of square edges  than sine-waves from rotating magnets.

Certainly both the line- and self- commutating thyristor based DC link stations generate some pretty unpleasantly rectangular current bursts and rely on other grid elements to spread what are in effect  current impulses more uniformly across the cycle. In the hopelessly simplified circuit below the upper wave-forms near the in and out terminals illustrate this. (The pale grey sine is voltage and the darker bumpy thing represents the general form of the current into or out of the grid) 

Instructions always say that a low impedance grid is needed to keep the voltage waveform from becoming more like that of the current. (sometimes expressed as harmonic content vs supply impedance)
Removing e.g. the French AC connection and leaving a large DC station on would perhaps  have been problematic in this way
M

This is the E&T magazine's summary of the report.    E&T magazine Iberian blackout

David

I note that mentions reactive power as well - but the authors have put it in quotes, as if thay are not sure if imaginary currents are quite as real as real ones ;-)

Hehe.

I've always thought that calling things phase shifted to be orthogonal relative to 'reality' 'imaginary' a very misleading choice of naming convention. Thanks maths department.  However, I'm not sure that the engineering folk calling it 'reactive' power is much better. Perhaps the metalanguage we use needs a bit of a rethink. 'Early and late' currents or 'tidal circulation' might be clearer. We need to imply the sort of rolling pay day loan of electrons with a lot of effort but nothing useful being done.
Mike