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What Happened in the UK Blackouts?

mitchoneill.com

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Re: What Happened in the UK Blackouts?

#51

Post by mitchoneill1 »

guerby wrote: post #47
mitchoneill1 wrote: post #28

Earlier quoted context omitted.

Hey! (author of the article here). I'm not happy with how I phrased this with the 4GW of capacity -- and while I suspect generation could have increased by hundreds of MW within 60 seconds I may be wrong. I've updated how I've phrased it in the blog to hopefully give a bit more clarity to my position. I don't meant to suggest that plants could ramp full within 60 seconds, it's that 4GW means there's a bunch of headro…

I assume battery based grid power stations like the Tesla one in Australia are amongst the best in class to help in this kind of crisis situation? Compared to the gaz turbine the system it is simpler (no mehanical/heat/fluid parts) and depending on design will likely never be completely off since made of dozens or hundreds of independant equipement (batteries and inverters). Thanks for the article and comment!

Batteries are great for this kind of stability support. I actually work for an Australian company that aggregates residential batteries together into MW-scale units and provides coordinated responses from 1,000 of kW-scale batteries that just as capable as a MW-scale plant (at a much lower cost of capital).

Here's one of our plants in Canberra which is past 3MW now, and is the first of its kind to be approved to bid into our fast frequency stability markets (where you have less than a couple of seconds to respond). https://www.youtube.com/watch?v=36UJMuC9-k0

Re: What Happened in the UK Blackouts?

#52

Post by lozenge »

aurbano wrote: post #41

It actually sounds like this was really useful though, as a lot of the systems involved will be improved in the future. I'm not sure if the grid is already doing this, but they should trigger failures randomly, including Low Frequency Demand Disconnection schemes from time to time to ensure that all downstream systems are also ready (like the hospital someone mentioned that had an issue with the backup generator, or…

Doesn't LFDD just mean cutting off large areas from the grid to improve the frequency elsewhere? I doubt it would be accepted by home users and businesses. Hospitals should be running their own local tests.

Re: What Happened in the UK Blackouts?

#53

Post by bartwe »

aurbano wrote: post #41

It actually sounds like this was really useful though, as a lot of the systems involved will be improved in the future. I'm not sure if the grid is already doing this, but they should trigger failures randomly, including Low Frequency Demand Disconnection schemes from time to time to ensure that all downstream systems are also ready (like the hospital someone mentioned that had an issue with the backup generator, or…

Well this was a chaosmonkey (the lightning) injecting a random fault ;)

Re: What Happened in the UK Blackouts?

#54

Post by stordoff »

pbhjpbhj wrote: post #37
Zenst wrote: post #8

Earlier quoted context omitted.

Nice article covering frfequncy importance at grid level:- https://www.drax.com/energy-policy/need-whole-country-freque... Though I'm not sure on the details of a frequency drop and impact upon your house in exacting details. Equally I'm not up on substations (did work on IT for large util company many decades ago, but not field engineering). But the first safety control from supply to the home, would be the distribu…

From that article: >"In Japan, the western half of the country runs at 60Hz, and the eastern half of the country runs at 50Hz – a string of power stations across the middle of the country steps up and down the frequency of the electricity as it flows between the two grids." // That's, err, curious.

It's largely a historical artifact:

> Eastern Japan (including Tokyo, Kawasaki, Sapporo, Yokohama, and Sendai) runs at 50 Hz; Western Japan (including Okinawa, Osaka, Kyoto, Kobe, Nagoya, Hiroshima) runs at 60 Hz. This originates from the first purchases of generators from AEG for Tokyo in 1895 and from General Electric for Osaka in 1896.

https://en.wikipedia.org/wiki/Electricity_sector_in_Japan#Tr...

Re: What Happened in the UK Blackouts?

#55

Post by noir_lord »

pm215 wrote: post #50
aurbano wrote: post #41

It actually sounds like this was really useful though, as a lot of the systems involved will be improved in the future. I'm not sure if the grid is already doing this, but they should trigger failures randomly, including Low Frequency Demand Disconnection schemes from time to time to ensure that all downstream systems are also ready (like the hospital someone mentioned that had an issue with the backup generator, or…

Triggering demand disconnection randomly is saying "we should provide consumers a service including deliberate random blackouts". That's OK in contexts like Netflix where the downstream systems are supposed to be able to be resilient to faults and failures are comparatively low-stakes anyway. But almost all grid consumers aren't resilient to power loss (would your house continue to be fully functional without noticea…

One of the hospitals affected by the blackout describe in this article had it's generators fail to come online cleanly, they had to go manual in ICU.

Re: What Happened in the UK Blackouts?

#56

Post by guerby »

mitchoneill1 wrote: post #51
guerby wrote: post #47

Earlier quoted context omitted.

I assume battery based grid power stations like the Tesla one in Australia are amongst the best in class to help in this kind of crisis situation? Compared to the gaz turbine the system it is simpler (no mehanical/heat/fluid parts) and depending on design will likely never be completely off since made of dozens or hundreds of independant equipement (batteries and inverters). Thanks for the article and comment!

Batteries are great for this kind of stability support. I actually work for an Australian company that aggregates residential batteries together into MW-scale units and provides coordinated responses from 1,000 of kW-scale batteries that just as capable as a MW-scale plant (at a much lower cost of capital). Here's one of our plants in Canberra which is past 3MW now, and is the first of its kind to be approved to bid…

Interesting! I've been following this through cleantechnica, electrek & other sites.

It's transforming a complex heat/fluid/mechanical system issue into a computer network and security issue. Usually the home network internet access market is very concentrated so a failure there could make the VPP unavailable. Solvable by putting control servers in various places and having each box connecting to multiple redundant control servers hosted with diversity and redundancy in mind.

Also ISM low bandwidth IoT radio technology like LoRa and sigfox might help redundancy too.

Might become important is VPP grows beyond handling rare grid events.

Re: What Happened in the UK Blackouts?

#57

Post by toyg »

pedrocr wrote: post #26
pm215 wrote: post #12

Earlier quoted context omitted.

A lot of the headline grabbing stuff wasn't the grid's fault though: * the railways didn't have traction power disconnected -- but one type of (new) train saw the within-specification frequency drop, shut down, and in many cases needed a fitter to go out and restart it. Everything else behind a dead train was stuck. I imagine the train company are discussing this with their supplier... * Ipswich hospital had a power…

In a way these events become a blessing in disguise because of those things. We've had to deal with similar crisis situations in our supply chain. It really helps to test your procedures and operations fixing stuff along the way. The team also gains experience and becomes much more prepared for worse events should they come.

I would go as far as suggesting that these things should be routinely tested. In the UK most public buildings test fire alarms once a week; a programmed plan of localised, managed blackouts, to be carried out once every few years, would probably help in the long run - particularly as the grid is rapidly changing as described at the end of the post.

Re: What Happened in the UK Blackouts?

#58

Post by topspin »

pm215 wrote: post #12
mytailorisrich wrote: post #6

Earlier quoted context omitted.

The issue with this specific outage is that it was badly managed. The main gripe people and authorities have with what happened is that key infrastructures immediately lost power. When (only) 5% of demand is turned off this should not impact railways, airports, and hospitals. Beyond the initial loss of power other problems amplified the consequences: For example, trains could not just restart but required specialist…

A lot of the headline grabbing stuff wasn't the grid's fault though: * the railways didn't have traction power disconnected -- but one type of (new) train saw the within-specification frequency drop, shut down, and in many cases needed a fitter to go out and restart it. Everything else behind a dead train was stuck. I imagine the train company are discussing this with their supplier... * Ipswich hospital had a power…

I read your list and see a bunch of 'technical debt.' Trains put into operation without the ability to survive a power transient without intervention. Life critical backup power system failures. The set of critical sites is not being maintained properly. In my mind these failures are are not entirely unrelated; reliable power is taken for granted and the testing and maintenance necessary to cope with power outages is neglected.

Re: What Happened in the UK Blackouts?

#59

Post by wongarsu »

mytailorisrich wrote: post #6
Zenst wrote: post #2

"Frequency drops below 48.8Hz which triggers the Low Frequency Demand Disconnection scheme (LFDD). Approximately 1GW (5% of total) of Great Britain electricity demand is turned off." Is interesting as it highlights the importance of managed failure. Things fail, but the ability to see those failures and control how that fails is important. Had such an action not been taken, the result would of been a far greater outa…

The issue with this specific outage is that it was badly managed. The main gripe people and authorities have with what happened is that key infrastructures immediately lost power. When (only) 5% of demand is turned off this should not impact railways, airports, and hospitals. Beyond the initial loss of power other problems amplified the consequences: For example, trains could not just restart but required specialist…

Here in Germany large industrial customers often get a cheaper electicity price in return for being the first to be cut in a load shedding scenario. If you are something like a steel mill then cheaper electicity quickly pays for slightly more frequent blackouts; and everyone else gets a more stable electricity network.

Re: What Happened in the UK Blackouts?

#60

Post by diggan »

To understand how/why these cascading failures can happen, Grady Hillhouse (Practical Engineering on YouTube) recently made a video about substations and what kind of faults can affect them, interesting if you're not super knowledgeable about our electric grids already: https://www.youtube.com/watch?v=7Q-aVBv7PWM
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