Any thoughts/information on what happened? Was it a lack of spinning reserve?
Was it " The Portuguese operator, REN, said the outage was caused by a “rare atmospheric phenomenon”, with extreme temperature variations in Spain causing “anomalous oscillations” in very high-voltage lines."
as is written in the Guardian?
The Italien blackout from a few years ago had a definate cause in the tripping of interconnetors from Switzerland during a storm.
There are a couple of posts on StackExchange physics.stackexchange.com/.../what-is-induced-atmospheric-vibration and electronics.stackexchange.com/.../what-are-induced-atmospheric-variations-and-how-do-they-cause-grid-desynchron with links to a report on the weak links of the Eurogrid (my term) highlighting the Iberia poor (weak) connection journals.aps.org/.../PhysRevResearch.7.013137.
The likelihood is that the multiplicity of cascading factors have become confused with each other (technologists attempting to talk to journalists).
I'm guessing it's dancing/galloping wires from the heat driven thermals; expanded, slack and distorted wires (aero effects), etc. causing clashing that either is a transient short with re-closure (load transfer / cascade, frequency 'sag'), or transient mischaracterised as low frequency. Either way they ended up with a cascade of protection dropping the whole peninsular.
Most of these 'failures' end up being classified on a 'for the want of a nail [peseta?]' slip/lapse/mistake excuse.
It is interesting than the fact that some of the physical explanations being given are clearly incorrect, which is probably due to a poor 'expert talking to journalists and politicians' interface, but we have seen that before.
More interesting to me, is the fact that it looks from the outside as if there was not a well rehearsed 'black start' process for bringing back small islands of generation and loads & synchronizing and connecting them onto the grid relatively automatically.
Given the huge synchronous interconnectedness of the Eurogrid, I'd have thought that would have been needed quite often, so a failure so long lasting seems a bit surprising unless distribution transformers or switchgear have been damaged at the same time . I think we will have to wait some time for logs to be studied and then a clearer picture to emerge.
Mike
“More interesting to me, is the fact that it looks from the outside as if there was not a well rehearsed 'black start' process for bringing back small islands of generation and loads & synchronizing and connecting them onto the grid relatively automatically.”
If I remember correctly ‘black starts’ are a form of cascade in the other direction. You would start with some diesels or small gas turbines which could start with their own batteries or compressed air tanks and then use this power to start small steam or gas turbine units and work up in size to the nuclear plants. All these generators bring rotary inertia and stability into the system.
Two weeks ago Spain was running on 100% ‘renewable’ electricity:
So other than Hydro (can this be used for black starts???) they had no synchronous power available. Solar and wind will trip on voltage or frequency errors. Nuclear is shut down on loss of offsite power on safety grounds.
I guess they had to bring some smaller thermal plants back into service before they could start recovering the grid.
Was solar/wind tripping part of the blackout in the UK in 2019?
Was solar/wind tripping part of the blackout in the UK in 2019?
As I recall it was "part" of what happened - but only because it tripped out exactly as the grid code said it should, rather than due to any particular characteristic of the technology itself. As I understand it the grid codes have since been revised...
If anything solar and wind should be some of the better choices for a black start - as they only need something to synchronise to, rather than large power source.
- Andy.
Was solar/wind tripping part of the blackout in the UK in 2019?
As I recall it was "part" of what happened - but only because it tripped out exactly as the grid code said it should, rather than due to any particular characteristic of the technology itself. As I understand it the grid codes have since been revised...
If anything solar and wind should be some of the better choices for a black start - as they only need something to synchronise to, rather than large power source.
- Andy.
If anything solar and wind should be some of the better choices for a black start -
Agree in principle, both due to no need to look for a source of ignition, and also as an inverter type process can decouple frequency from voltage, in a way that a conventional generator can not.
But the current rules of engagement actually make that a disadvantage, as they are written for 'spinning' generators, from a time when it was safe to assume the non-inertial devices are the small part that can safely be thrown off.
It may be part of the problem that we need to get away from assuming that a falling frequency is a reliable indicator of an overload, or handling such behaviour needs to be programmed in.
On the other hand, once spinning, a real genset has much more ability to ride through inrush overloads that are inevitable as things come back on, so a more granular approach to load ramp up may be needed.
Actually at much smaller scale the inverter type variable engine speed generators don't play well when you try and sync them either.
It is really far to soon to be sure what happened here, so this is just speculative, but I think there will be some lessons to learn once it is clearer.
Mike.
a minor technical point, but the main reason that frequency fell in 2019 was that two large generators tripped off when they shouldn't. one was CCGT, the other offshore wind, and both were heavily penalised by the regulator Companies pay £10.5 million over 9 August power cut | Ofgem
Thanks for that Dave. Digging though that and its references, it does look like it was more "interesting" than previously reported.
of Hornsea 1, one report says:
3.21. We have found that the wind farm’s onshore control system operated as expected
when the system voltage dipped concurrently with the lightning strike. The offshore
wind turbine controllers, however, reacted incorrectly to voltage fluctuations on the
offshore network following the fault. This caused an instability between the onshore
control system and the individual wind turbines. The instability triggered two
modules to automatically shut down.
which seems to suggest that while the shore side did behave correctly according to the grid codes, the offshore (and/or connection) bit didn't.
There was also a loss of distributed generation:
2.4.6. The level of power loss (or increase in net demand on the electricity system)
caused the frequency of the electricity system to fall at a rate of change of
frequency (RoCoF) above 0.125Hz/s. Some distributed generators operating
under legacy Distribution Code requirements have loss of mains protection
mechanisms triggered by RoCoF set at this rate. As a result, an estimated 350-
430MW of distributed generation tripped off unnecessarily, based on
information provided by the ESO19.
- Andy.
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