Report on recent widespread power cut in UK - Page 1
Forum section: electronics / general

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: August 20, 2019, 09:27:15 pm
content: Interesting read, The more I learn about the complexities of national power distribution the more I'm amazed at how reliable it all ishttps://www.nationalgrideso.com/document/151081/download

author: fourtytwo42
author_rank: Super Contributor
timestamp: August 21, 2019, 01:01:53 pm
content: Seems as usual with these things despite all the shrill squawking in the media everything worked as intended, some idiot on the radio this morning was asking how big the fines would be levied by the regulator upon national gridbut then that was a BBC journo (so called).The only obvious flaw is some numkin forgot to test the fancy foreign rolling stock properly or specify it adequately. Same goes for the signalling power supplies except it's source is unknown......how on earth does somebody design a psu so badly it locks itself out as a result of a minor droop in grid frequency, sounds totally unfit for purpose to me!!

author: Someone
author_rank: Super Contributor
timestamp: August 21, 2019, 11:37:40 pm
content: Quote from: fourtytwo42 on August 21, 2019, 01:01:53 pmThese are all configurable "safety" systems, different operators/regions all have different requirements for large loads/generators to disconnect. Its not surprising that the trains required a technician to reset them with some procedure the drivers did not know of, it could even have been an intentional design to avoid repeated attempts to restart.TLDR, huge complex system of many interconnected devices had some of them configured with cutoff limits that weren't what the regulator/operator expected from their specifications

author: fourtytwo42
author_rank: Super Contributor
timestamp: August 23, 2019, 08:11:41 am
content: Quote from: Someone on August 21, 2019, 11:37:40 pmComes to the same thing configurable or not, those responsible for defining the settings were obviously inadequately qualified and insufficiently supervised. Load shedding is not required at that level as a train only consumes a few megawatts, reliability of service is required and rightly expected, poorly trained, supervised and in particular inexperienced staff should not be allowed to tamper with such equipment nor define how it is to operate IMOP.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: August 23, 2019, 08:26:27 am
content: Pretty stupid that a tech had to physically go out to reset though - this is the sort of thing that should be handled by remote management, or a code entry on a keypad etc.

author: KD8FJH
author_rank: Newbie
timestamp: August 23, 2019, 01:33:50 pm
content: Many power grid protection systems use Lock-Out relays to prevent a close or auto-reclose into a faulted line. Most are manually reset by a line worker that has verified the problem has been remedied.It mostly comes down to safety reasons, but also to prevent further equipment damage by a remote operator trying to close in on faulty equipment.Like many things, unless you know the reasons behind it, it may seem stupid at first, but there is a reason behind it. I've worked in EHV power transmission for about 20 years now, and I still learn something new almost every day about how "the grid" works.

author: tggzzz
author_rank: Super Contributor
timestamp: August 23, 2019, 06:44:41 pm
content: Quote from: mikeselectricstuff on August 23, 2019, 08:26:27 amYou need to think how remote management might operate in a way that generates a KSI statistic. These things are often a compromise between competing requirements.Having said that, I'm surprised that some (but not all) trains couldn't be restarted by onboard personnel.

author: temperance
author_rank: Super Contributor
timestamp: September 06, 2019, 05:03:26 pm
content: @mikeselectricstuffI once downloaded a book on power grids. A fascinating book full of chicken scratching maths. Transmission lines (50/60Hz and extremely long cables), kV thyristors stacked to switch mega Volts DC into,... And they got all this to work when technology was still in diapers.Imagine the conversations when thigs like that were being switched on for the first time. And I'm scared to switch on an offline SMPS proto-type for the first time. I'm probably a chicken without steel balls or something.

author: Towger
author_rank: Super Contributor
timestamp: September 07, 2019, 10:50:21 am
content: I believe the official report was supposed to be published yesterday...

author: TerraHertz
author_rank: Super Contributor
timestamp: September 13, 2019, 06:21:00 am
content: Quite relevant:http://joannenova.com.au/2019/09/burn-money-wind-farms-in-tas-and-vic-are-correlated-all-useless-at-the-same-time/Burn Money: wind farms in Tas and Vic are “correlated” — all useless at the same timeTalking about the proposed new “largest wind farm in the Southern Hemisphere” on Robbins Island (Tasmania), a new Baslink cable to the mainland, and predictable destabilizing effects on the Australian national grid.

author: tggzzz
author_rank: Super Contributor
timestamp: September 13, 2019, 06:49:50 am
content: Quote from: TerraHertz on September 13, 2019, 06:21:00 amNo comment about that link, but there's a useful rule of thumb in the UK based on the data inhttp://www.gridwatch.templar.co.uk/If the aggergate UK peak wind power output is P, then actual power output is below xP for fraction x of the time. In other words 1% of the time it is below 1% of peak output, 10% of the time below 10% of peak etc. Yes, for 3 days/year the output is below 1% of peak output.Now, who does and should pay to keep the conventional plant available when the windisn'tblowing?Note to rabid ignorant greens: if the wind isn't blowinghereitwon'tnecessarily be blowingthere.

author: Someone
author_rank: Super Contributor
timestamp: September 13, 2019, 08:18:32 am
content: Quote from: TerraHertz on September 13, 2019, 06:21:00 amIt makes plainly ridiculous assumptions to support their point of view. Lulls in generation from wind farms are predictable far enough in advance and with enough accuracy that the slower generators such a coal can be scheduled to support the grid, so even if the power is very highly correlated with existing wind sources thats not the huge problem they make it out to be. What they don't mention is the continuing awful reliability of the ageing coal fleet.Would more renewables in the grid reduce the profits of coal plants and force some of them to close? Sure will, and the end result for the market is lower cost energy.Quote from: tggzzz on September 13, 2019, 06:49:50 amDifferent ways to account for the capacity:https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/728374/UK_Energy_in_Brief_2018.pdfThe UK doesn't regard the renewables as reliable capacity in factoring their capacity margin. But happily takes 1/3 of generation from renewables, wind and solar over 20% of the total generation:https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/791297/Press_Notice_March_2019.pdfCompare to Australia:https://www.aer.gov.au/wholesale-markets/wholesale-statistics/generation-capacity-and-output-by-fuel-sourceEven with more hydro available (as a percentage) for reliable dispatch to back the intermittent renewables, wind/solar does not even hit 10% of generation. You can't go 100% renewable immediately, but Australia has a lot of capacity to take up more renewable generation. The UK shows its possible and reliable.