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What Happened in the UK Blackouts?

mitchoneill.com

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Re: What Happened in the UK Blackouts?

#91

Post by IAmGraydon »

londons_explore wrote: post #16

It's notable that this report is completely consistent so far with the way I would design a cyber attack to take out a countries power grid. > The causes provided by RWE for the initiation of the trip of Little Barford steam turbine (ST1C) was due to discrepancies on three independent safety critical speed measurement signals to the generator control system. A cyber attack would most likely, rather than directly take…

Except that you would have no control over when the outage happens as you would have to wait around for a random lightning strike to initiate the chain reaction. This outage lasted a very short time. An attacker would likely want to take advantage of the power loss in some way, meaning control over the timing would be pretty important.

Re: What Happened in the UK Blackouts?

#92

Post by 7952 »

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…

The best time to test a generator backup is when the grid power is still available. So that you can revert if the generator fails to start.

Re: What Happened in the UK Blackouts?

#93

Post by 7952 »

mitchoneill1 wrote: post #28
pm215 wrote: post #20

The article says near the bottom "At the time [the GT1A generator tripped] there was 4000MW of unused generation in reserve, and if only a fraction of this reserve was instructed to dispatch within 60 seconds of the initial loss it’s very likely that load shedding would have not occurred." My understanding was that having reserves available within 30-60s was pretty expensive, and that that would have been what was us…

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…

Is grid frequency not a good enough signal in its own right to increase production?

Re: What Happened in the UK Blackouts?

#94

Post by karamitru »

eDISCO wrote: post #10

Most traditional generators (think CCGT, nuclear, hydro) run in synchronous mode. Which means the generators spins with rpm proportional/equal to the network frequency. For 50Hz that would be 3000rpm. When the total electricity demand exceeds the supply, the kinetic energy of spinning generators is converted to electricity which slows down the generator rpm, which reduces the frequency. All synchronous generators on…

There was a comment once on HN that once a power generator was hooked to the network without the phases being aligned, and the resulting mechanical forces were so large that the generator got unbolted from the floor and flew through the air. Not sure if true or not.

Re: What Happened in the UK Blackouts?

#95

Post by timthorn »

wongarsu wrote: post #59
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…

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.

That's the case in the UK too.

Re: What Happened in the UK Blackouts?

#96

Post by mellosouls »

mytailorisrich wrote: post #14
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…

I did mention the railways and indeed the importance of making sure the whole system can cope, which means what you list in addition to the grid in isolation. > None of these seem like "bad management" They do seem like bad management because to me it looks like these issues were not taken seriously. > problems of the sort you're likely to run into if you have to activate an emergency procedure you haven't needed to…

Reading this exchange as a third party, both sides make fair points, but one side is being excessively downvoted, which is either unfortunate or possibly a regrettable sign of emotional over intellectual engagement in the discussion somewhere.

Re: What Happened in the UK Blackouts?

#98

Post by 4rt »

diggan wrote: post #60

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

I always upvote grady. It's great to see his subscriber count finally starting to match the quality of his videos.

Re: What Happened in the UK Blackouts?

#99

Post by the_mitsuhiko »

rcxdude wrote: post #61
fyfy18 wrote: post #3

What affect does the frequency drop have to home users? Is there protection in the substations near to homes that will cut off the power completely if the frequency goes out of range?

The grid frequency itself doesn't matter much as far as consumers are concerned, the deviations mentioned in this article would not cause any problems for a home user directly (or even generators, but as mentioned below if it is too far out of range generators start to need to cut out) but it is a far better indicator of the general balance of supply and demand of power in the grid than any other metric, because it c…

> The grid frequency itself doesn't matter much as far as consumers are concerned

So I thought and then we had a multi week frequency shift in the EU and various clocks started lagging behind. This does show up for consumers as well.

Re: What Happened in the UK Blackouts?

#100

Post by jimmaswell »

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…

A potential argument against transit reliance, or at least trains relying on the grid to keep running (instead of using batteries or diesel). Personal transport options (cars, bikes, horses) are a decentralization success story when the grid goes down.
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