Author Topic: Did the UK come closer than regulation proscribes to a black out?  (Read 3926 times)

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Offline mzzj

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Re: Did the UK come closer than regulation proscribes to a black out?
« Reply #50 on: January 18, 2025, 10:10:07 pm »
In this context, "inertia" is the literally correct term. When a generator is suddenly disconnected the other generators struggle to take up the load, the conventional rotating generators slow down, and the frequency drops. There is a lot of energy stored in the heavy rotating lumps of metal, and that is used to supply energy for a critical few seconds until other sources take up the load.

There is far less energy stored in the rotation of renewables generators, so the frequency drops more and faster. In bad cases it drops so far that other generators disconnect themselves for protection. A classic cascading failure.

Batteries can come online more or less instantly; they don't need much capacity, merely sufficient for the few seconds mentioned above. The batteries supply the equivalent of inertia to the system.

And that is why batteries can be economic: they can charge astronomically high prices for the critical few seconds.
AFAIK problem with renewables generators is not lack of inertia but the one-way inverters.

VFD/inverter use in industry motor uses has also reduced the load inertia. Large synchronous motor provides similarly helpful inertia to the grid as the generators do but if there is a VFD between the grid and the motor you lose the inertia.

Large generators or motors can also supply stupidious amounts of power to the grid for short periods and it still makes them desirable compared to battery-inverter systems that are more limited in short-circuit current capabilities.  Thus the installation of synchronous condensers that are basically free-running motors that only provide inertia to the system.
« Last Edit: January 18, 2025, 10:11:48 pm by mzzj »
 
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Offline tggzzz

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Re: Did the UK come closer than regulation proscribes to a black out?
« Reply #51 on: January 18, 2025, 10:34:35 pm »
Generators and loads have many many characteristics that will always be changing and will require adaptation. Some of those characteristics have been given specific names.

When comparing X1 with X2 with Y1 with Z3 to see which is better/worse, adjectives are insufficient: numbers are necessary.
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Offline Someone

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Re: Did the UK come closer than regulation proscribes to a black out?
« Reply #52 on: January 18, 2025, 11:13:21 pm »
Generators and loads have many many characteristics that will always be changing and will require adaptation. Some of those characteristics have been given specific names.

When comparing X1 with X2 with Y1 with Z3 to see which is better/worse, adjectives are insufficient: numbers are necessary.
Sadly there is not yet any uniform language around this, in Australia there is some distinction between FFR and FCAS as inertia with well defined "run times" before being depleted to cover the slewing of other generators. But is that "fast frequency response" or " fast frequency reserve" ?

Solar/wind being curtailed yet not being able to bid for frequency reserve is evidence of the system being completely broken economically.
 

Offline coppice

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Re: Did the UK come closer than regulation proscribes to a black out?
« Reply #53 on: January 19, 2025, 10:24:51 pm »
In the last 2 days, every time I watch something on YouTube I get ads from the UK National Grid telling me to go to their web site and find how to prepare for a black out. They try to be very upbeat about the issue.
 

Offline richard.cs

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Re: Did the UK come closer than regulation proscribes to a black out?
« Reply #54 on: January 20, 2025, 11:55:03 am »
It's not like as lack of spinning reserve would actually cause the general public to experience blackouts anyway. Rather some frequency sensitive load shedding relays would trip kicking a bunch of refrigerated warehouses and similarly interruptible industrial loads off supply (they are paid to be available for this, and paid more if used). Those are then expected to get reconnected over the following 30 minutes or so as additional generation is bought online.

There are real grid stability problems that need some work, for example we have issues about protection settings on inverter-connected generation, especially over-zealous anti-islanding that can kick a load of embedded generation offline when the frequency drops. That was a significant contributor to the August 2019 event. But the video seems to be a nothing story, as PaulCA says it's mostly a possible paperwork/code of conduct issue.

UK nuclear is another issue entirely. We're in the process of unnecessarily shutting down the last few AGRs because no-one wants to pay to generate the paperwork for further life extensions.
 
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Offline watchmaker

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Re: Did the UK come closer than regulation proscribes to a black out?
« Reply #55 on: January 20, 2025, 12:35:36 pm »
This is not just a UK thing.  We are heading to distribution problem in New England as we shift to weather dependent power sources.

See https://www.eevblog.com/forum/chat/power-distribution-in-new-england/msg5776709/#msg5776709
Regards,

Dewey
 

Offline Marco

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Re: Did the UK come closer than regulation proscribes to a black out?
« Reply #56 on: January 20, 2025, 06:42:53 pm »
Germany is commissioning 12.5 GW of new gas powered generation BTW (hydrogen ready, in theory, if the EU still exists by then). That's a pretty hefty amount, multiplied by 3 it would be enough :)
« Last Edit: January 20, 2025, 06:45:13 pm by Marco »
 

Online Analog Kid

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Re: Did the UK come closer than regulation proscribes to a black out?
« Reply #57 on: January 20, 2025, 11:06:47 pm »
Batteries can come online more or less instantly; they don't need much capacity, merely sufficient for the few seconds mentioned above. The batteries supply the equivalent of inertia to the system.

Don't want to quibble too much here, but it's not just batteries that need to "come online" but the associated controller circuitry, which I can imagine might take longer than a few seconds to come up to operating condition and allow the batteries to start pouring their power into the grid. (Grid-tie oscillators have to come into sync with the line frequency, etc.)
 

Offline coppice

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Re: Did the UK come closer than regulation proscribes to a black out?
« Reply #58 on: January 20, 2025, 11:27:51 pm »
Batteries can come online more or less instantly; they don't need much capacity, merely sufficient for the few seconds mentioned above. The batteries supply the equivalent of inertia to the system.

Don't want to quibble too much here, but it's not just batteries that need to "come online" but the associated controller circuitry, which I can imagine might take longer than a few seconds to come up to operating condition and allow the batteries to start pouring their power into the grid. (Grid-tie oscillators have to come into sync with the line frequency, etc.)
Why would they not already be in sync when they are needed? They are monitoring the network all the time, waiting for a problem event. These systems can come on line extremely quickly. Their limitation is really the maximum discharge rate specified for the batteries. I don't think any of them can be set up to drain in a few seconds. They need to have a lot more capacity than that.
 
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Online Siwastaja

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Re: Did the UK come closer than regulation proscribes to a black out?
« Reply #59 on: January 21, 2025, 06:26:17 am »
Don't want to quibble too much here, but it's not just batteries that need to "come online" but the associated controller circuitry, which I can imagine might take longer than a few seconds to come up to operating condition and allow the batteries to start pouring their power into the grid. (Grid-tie oscillators have to come into sync with the line frequency, etc.)

Batteries can most definitely respond within tens of milliseconds. I'm not sure about large-scale grid batteries, but they might have some "sleep" states available to reduce quiescent current consumption (compared to keeping the power stage running at zero power), but that state would be entered only when it's certain that there will be no quick requests for output power. I don't know if the quiescent draw while in "running" mode is significant enough at all for this to matter anyway, probably not.
 

Offline paulcaTopic starter

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Re: Did the UK come closer than regulation proscribes to a black out?
« Reply #60 on: January 21, 2025, 09:38:15 am »
I know my micro inverter has a "sleep mode".  If the power draw is under 7W it stops producing a high sample point pilot wave and produces a rather blocky rubbish sine wave.  This apparently reduces the "waste" significantly.  The idea is also that tiny little residual loads are likely not going to care if they get a "stepped triangle" wave rather than a sine.

I run a strip of LED lights all night on it.  When it's inverting it does take about 7W to run a set of 2W LED lights.
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Offline max_torque

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Re: Did the UK come closer than regulation proscribes to a black out?
« Reply #61 on: February 01, 2025, 12:34:27 pm »
missinformation and out-of-date thinking are ripe here, as CCdeniers and fossilfuel FUDs rule the worm riddling brains of the terminally thick...


People still talk about issues "with kettles turning on during the world cup" or during the advert breaks in East Eneders of what ever, but this is tragicaly out of date.  The problem back them was two fold, 1) lots of people all doing the same thing at the same moment  which is not true any more as we are no longer welded to our living room tvs at 7.00pm exactly syncronised by terestrial live telly and 2) our mostly coal fired powerstartions took ages to ramp up / down due to their massive thermal inertia.  Our grid is much more dynamic and agile now, so the problem of it being a weekend with  little industrial load (the major consumer of our electricity) and hence coal fired stations being at idle, and then everyone having a cup of tea at world cup half time are long gone.


We also have a much better arrangement of load spreading. Most loads are actually "shedable" at the right price, even loads you might consider important.  Huge inductrial users are lined up for, and get a good cost saving from, specific deals that mean they get shed first, keeping the "lights on" for the general public.


It's also worth noting that "blaming everyone else and just moaning" doesn't get you anywhere in life.  The grid powersupply to my house and this computer could stop right now and i wouldn't even notice, because i have a second hand EV battery and solar array that can run my entire house for several days (hint, EV batteries are massive, my Gen2 nissan leaf battery was 42kWH when new, and now some 7 years later at the C rates it sees for my domestic application it's still capable of buffering around 39kWh of energy, and it cost just £1,800.  It actually has already paid for itself because i use no "expensive rate" 'lecy at all now. I use roughly 50% from the solar and 50% from the grid, but charging at the cheapest off peak rate has quartered by 'lecy bill.


So if you see "renewables" as a problem that's fine, but the actual problem is that you are stuck in the past............

 
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Offline coppice

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Re: Did the UK come closer than regulation proscribes to a black out?
« Reply #62 on: February 01, 2025, 03:16:37 pm »
So if you see "renewables" as a problem that's fine, but the actual problem is that you are stuck in the past............
Who has said renewables are a problem? The problem is zealots pushing them into service, and pulling other stuff out of service, with little understanding, and a weak regard for ensuring a stable and affordable service to the consumer.
 

Offline watchmaker

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Re: Did the UK come closer than regulation proscribes to a black out?
« Reply #63 on: February 02, 2025, 01:24:17 pm »
missinformation and out-of-date thinking are ripe here, as CCdeniers and fossilfuel FUDs rule the worm riddling brains of the terminally thick...



So if you see "renewables" as a problem that's fine, but the actual problem is that you are stuck in the past............

See post 55 which references this report:  https://rifreedom.org/wp-content/uploads/ISO-NE-r3d-final.pdf

I use a heat pump down to -3 F and a heat pump water heater.  I also have 6.5KWH solar installation.  But as this report points out, as more New Englanders do this and state policy makers discourage non weather dependent, dispatchable power sources (nuclear, carbon) we are going to run into a crunch during the colder, darker, cloudier days of winter.

We are going to have a continuing need for non weather dependent power sources; this issue is highly geographically dependent.  Not a major issue in California or Arizona, but a serious one to consider in New England.

And, we do not have the capacity to transmit electricity not used on the west coast 3,000 miles to the east coast.

At this point in my life, I favor nuclear as that source.

Also, as a naturalist, I do not think we can "protect" every hill and viewshed at the expense of the greater good.  But far too many people look at things from only one point of view and fail to see the big picture.
Regards,

Dewey
 

Offline coppice

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Re: Did the UK come closer than regulation proscribes to a black out?
« Reply #64 on: February 07, 2025, 11:34:12 am »
In the last 2 days, every time I watch something on YouTube I get ads from the UK National Grid telling me to go to their web site and find how to prepare for a black out. They try to be very upbeat about the issue.
3 weeks later and they are really cranking up these prepare for black out ads. We are getting black outs, too. So, far they are feeling more like grid maintenance has gone downhill, and each storm results in power going off to people who haven't previously seen a power failure in a couple of decades. It would be hard to tell from the outside if its really that, or some form of load shedding. When the power failed here last week, the national grid map of power outages showed a large area around York (my home) having a lot of failure reports. However, they cleared step by step over a day, so they may have been due to a number of separate failures. It was the day after a big storm. Things were OK through its maximum.

Just had another 10 minute power cut. Slight rain outside, but not a serious storm. The UK grid is starting to suck.
« Last Edit: February 08, 2025, 08:36:48 pm by coppice »
 

Offline DenzilPenberthy

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Re: Did the UK come closer than regulation proscribes to a black out?
« Reply #65 on: February 07, 2025, 05:13:26 pm »
I'm late to the party and only just seen this thread,

A thing worth remembering when talking about the ability of things like pumped storage to cope with grid trips etc, is that when they are not generating, they are pumping.

If something big trips off the grid and there is a 1GW deficit, you can solve that two ways. Either bring on 1GW of generation immediately, or drop 1GW of load.  If the event happens when the pumped storage is pumping, they can be asked to stop pumping temporarily and reduce demand significantly which also solves the problem.

Relevant to this topic, I recently stumbled across this YouTube podcast called Transmission by a company called Modo Energy (who seem to be doing something data sciencey with all of the data needed to juggle all of of the generator sources etc)

They have some really interesting and (with some actual technical depth) interviews with very high level people about all of these topics.

e.g. role of batteries in future energy scenarios with Director of Strategy & Policy at ESO (which is the organisation that sets policy for this stuff in the UK)


Inertia, stability issues, need for synchronous compensators etc with Head of Grid Integration UK at Europe's biggest renewable energy company


I listened to a bunch yesterday and found them really interesting (and quite reassuring)

 


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