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Leaked Report Points To Wind Farm Failure Causing UK Blackout

August 17, 2019

By Paul Homewood

 

 

GWPF have news of this report from the FT (unfortunately pay-walled):

 image

The provisional report, which was submitted to regulators on Friday, suggests for the first time that the Hornsea offshore wind farm, which is owned and run by Denmark’s Orsted, may have tripped offline seconds before an outage at a smaller, gas-fired station.

The findings, which were relayed to the Financial Times by people briefed on the report, suggest the blackout may have been avoided if not for an error at the wind farm.

Full story (£)

 

It would seem to confirm what some commenters here have suggested, that it was Hornsea which tripped first.

If anybody sees a fuller version in other newspapers, please let me know.

17 Comments
  1. August 17, 2019 11:36 am

    Reblogged this on ajmarciniak and commented:
    The provisional report, which was submitted to regulators on Friday, suggests for the first time that the Hornsea offshore wind farm, which is owned and run by Denmark’s Orsted, may have tripped offline seconds before an outage at a smaller, gas-fired station.

    The findings, which were relayed to the Financial Times by people briefed on the report, suggest the blackout may have been avoided if not for an error at the wind farm.

  2. dearieme permalink
    August 17, 2019 12:14 pm

    Open a private window (Mac) or use incognito (PC?). In your search engine enter:

    National Grid electricity blackout report points to failure at wind farm

    and then look at the output list for the link to the FT article. Click through.

  3. george mereditch permalink
    August 17, 2019 12:18 pm

    FT article

    National Grid electricity blackout report points to failure at wind farm

    Initial probe raises the possibility that chaos was caused by new plant
    The Jack-up construction vessel Brave Tern installing turbines at the
    Hornsea 1 offshore wind farm © Alamy

    David Sheppard in London and Nathalie Thomas in Edinburgh yesterday

    National Grid’s preliminary investigation into the blackout that caused
    widespread disruption in
    England and Wales last week has raised the possibility that it was
    caused by the world’s largest offshore wind farm accidentally going offline.

    The provisional report, which was submitted to regulators on Friday,
    suggests for the first time that the Hornsea offshore wind farm, which
    is owned and run by Denmark’s Orsted, may have tripped offline seconds
    before an outage at a smaller, gas-fired station.

    The findings, which were relayed to the Financial Times by people
    briefed on the report, suggest the blackout may have been avoided if not
    for an error at the wind farm.

    Investigators had originally thought the shutdown of the Little Barford
    gas-fired plant in St Neots, west of Cambridge, had triggered a domino
    effect across the network that led to the blackout.

    Investigators now suspect the problems on the grid started when
    lightning hit part of the network near Cambridge. This caused
    300MW-400MW of capacity in the local electricity network, which normally
    means small-scale renewable power, to go offline. Such a small outage
    should not have caused any problem for the wider grid. Lightning strikes
    are common on National Grid infrastructure, which is hit on average
    three times per day, and they rarely cause serious problems.

    But the strike coincided with the almost instantaneous total loss of
    supply from the Hornsea wind farm, which lies off the coast of
    Yorkshire. The facility, which is still under construction, was
    generating as much as 800MW for the grid last Friday afternoon before
    cutting to 0MW in less than a second.

    National Grid’s report is expected to say this detail is significant
    because it was previously believed the loss of power took approximately
    60 seconds. The instant shutdown suggests the safety systems at Hornsea
    could have taken the plant offline accidentally.

    Analysts have speculated that Hornsea may have disconnected from the
    grid if its safety systems were configured too sensitively to drops in
    frequency — a measure of stability of an electricity system. The UK grid
    is designed to be held in a narrow band near 50 hertz but power plants
    should not disconnect unless the frequency oscillates sharply.

    Orsted acknowledged on Friday that a “technical fault” had meant that
    the wind farm “rapidly de-loaded”, but declined to comment on whether
    Hornsea had failed before Little Barford.

    The company said it had since made adjustments to “the relevant part of
    the system”.

    “We are fully confident should this extremely rare situation arise
    again, Hornsea One would respond as required.”

    The report is expected to indicate that the frequency of the grid did
    not plunge to 48.8 hertz — a level that triggers National Grid’s
    automated system to cut off electricity supply to around 5 per cent of
    demand — until the first generator tripped at Little Barford, joining
    Hornsea offline. Blackouts followed as the automated system kicked in.

    Other preliminary findings in the report are that the National Grid had
    only 1,000MW of rapid-response emergency supply at the time, just
    two-thirds of the amount that was eventually lost.

    A broader government investigation is expected to focus, in part, on
    whether the grid should have more of this reserve supply in the future.

    The report is also expected to show that eight rail-signalling networks
    lost power supplies across the country, leading to much of the chaos on
    the railways in England and Wales.

    Power to overhead lines on train tracks were, however, largely
    maintained, but the issue was exacerbated by a number of trains that
    shut down automatically and could not be restarted by their drivers.
    Govia Thameslink, which had as many as 60 trains affected, said it had
    to call out engineers to restart half of those that failed.

    Steve White, chief operating officer at the train group, said that their
    own preliminary investigation had established a drop in electrical
    frequency on the overhead power lines, which triggered safety mechanisms
    on the shut down trains.

    National Grid declined to comment.

    /Additional reporting by Janina Conboye in London/

  4. Tony Budd permalink
    August 17, 2019 12:30 pm

    Paul: Nobody seems to be admitting that the winds in the North Sea were very strong and gusty that evening and were rapidly increasing in strength. The most likely scenario still seems to me to be that output from Hornsea was increasing sharply and that that triggered the gas plant to start going offline because its input was then unnecessary, just at the point when the wind became too strong for Hornsea to cope with any more, and so it shut down. Yours, Tony Budd

    • It doesn't add up... permalink
      August 17, 2019 2:26 pm

      Wind was producing rather more overnight and in the early morning that at the time of the outage. Wind speed was quite some way short of the 90kph at which cutout occurs, and in any event, a gust of wind would take several minutes to cross the wind farm because it is so extensive (407sq km) – and it would be attenuated by the other turbines on the way. Also, the turbines have High Wind Ride Through technology, which means that even if the wind speed reaches the cutout level, generation is decreased gradually rather than instantaneously. No other offshore wind farm appears to have been affected.

      It does seem as though the Grid should have been asking for wind farms to curtail output. On the Saturday (when it was windier than it had been on the Friday) that is exactly what they did, to ensure enough reliable inertia was online. In fact, the Telegraph reported that Hornsea got almost £100,000 in curtailment payments for that.

      • It doesn't add up... permalink
        August 17, 2019 5:08 pm

        From what I can now see, it seems the Telegraph got their report wrong. While there is evidence of curtailment at the overall national level on Saturday, it did not apply to Hornsea in any meaningful sense. Hornsea spent the entire day generating at a rock steady 780MW, as if demonstrating how stable they can maintain their output in strong winds.

        Little Barford did not restart after the trip until about 7 p.m. on Saturday, and was running around half capacity later in the evening.

      • August 17, 2019 6:41 pm

        Wasn’t the problem that there was too much power across all the grid, not just at Hornsea?

  5. August 17, 2019 1:06 pm

    Reblogged this on Climate- Science.press.

  6. Kevin permalink
    August 17, 2019 1:59 pm

    Just before the blackout National Grid and RenewableUK had been bragging about a new record for wind generation. Strange that this was never mentioned again.

    • Jordan permalink
      August 19, 2019 8:59 pm

      I trust this marks the end of drip-drip of greenwash and carbo-feelgoodery from NG. Such as how long they have operated with no coal fired generation.

      GB now needs to learn the true value on coal stored at the power station. The future will have over 10 GW of intermittent supply, impossible to predict more than a couple of days into the future. A freezing mid-winter blocking high pressure system over NW Europe this year would be timely.

  7. August 17, 2019 2:50 pm

    The 2008 report isn’t exactly easy to find but worth having a look at because the events then were reasonably independent unlike Aug 9. Compare the frequency transient to the leaked one in the FT –

    https://web.archive.org/web/20100206093023/http://www.nationalgrid.com/NR/rdonlyres/E19B4740-C056-4795-A567-91725ECF799B/32165/PublicFrequencyDeviationReport.pdf

  8. Nicholas Lewis permalink
    August 17, 2019 3:06 pm

    Until the full technical report is released on 6th September we wont really know the true sequence of events and what specific protection systems caused forced trippings or the underlying mechanical causes of loss of load at Hornsea and Little Barford. However, interesting to note that Coal has been in almost daily use since last Friday no doubt to keep system inertia up but there wont be any bragging about that by NG or in the dailies.

  9. MrGrimNasty permalink
    August 17, 2019 7:07 pm

    A few days ago there was mention of how cloud might affect solar PV in the UK – after claims it produced regardless. Well looking at the grid status (model I know) it’s seems it produces only 1/3 the peak on a sunny day, 2 v 6GW.

  10. Athelstan. permalink
    August 17, 2019 8:11 pm

    Paul,

    Emms (Gosden) has a puff piece in the Sat’ Times, printed in the Business pages, entitled,

    “Can lightning strike yet again on the grid?”

  11. John Cooknell permalink
    August 19, 2019 8:34 am

    The report will not say that the root cause of the outage is that the grid was not designed to have so many embedded generators, and there is little that can be done to improve things.

  12. It doesn't add up... permalink
    August 20, 2019 9:40 am

    The report is in:

    At 16:52:33 on Friday there were a number of lightning strikes on the transmission network north of London. This triggered the transmission line protection to disconnect and clear the disturbance (in c.70milliseconds) plus initiate its subsequent reconnection (automatically after c.20 seconds). This operated as normal and the voltage disturbance on the network from the lightning was within expected limits for such an event.
    As would be expected in such circumstances there was the loss of some small embedded distributed generation (totalling ~500MW) associated with the transient voltage disturbance caused by the lightning.
    Almost simultaneously, and unexpectedly, two large transmission connected generators reduced their output onto the system.

    Power Loss
    • The lightning strike and rapid frequency fall caused the loss of ~500MW of Distribution connected generation, likely to be solar and some small gas and diesel fired generation, due to the operation of the generation sources own protection systems (Loss of Mains Protectioni)
    • Hornsea One offshore wind immediately lost Hornsea modules 2 and 3, totalling 737MW. Module 1 continued to operate smoothly at 50MW throughout the event.
    • Little Barford Gas Power Station – near immediate loss of the Steam Turbine unit (244MW) and then, as a result of the loss of the steam unit, loss of the two Gas Turbine units (total station loss of 641MW) over the following 90 seconds.

    https://www.ofgem.gov.uk/system/files/docs/2019/08/incident_report_lfdd_-_summary_-_final.pdf

  13. Ivan permalink
    August 20, 2019 9:48 am

    Ofgem have published National Grid’s report.
    https://www.ofgem.gov.uk/system/files/docs/2019/08/incident_report_lfdd_-_summary_-_final.pdf

    Very brief summary:
    – 3 particular lightning strikes on some distribution equipment (there were many such that day)
    – 500MW of embedded generation in the area went off as self-protection – as expected, and handled properly
    – Then Hornsea (799MW at the moment) went off in an internal cascade as a result of internal protection devices responding to frequency fluctuations and then cascading through
    – Seconds later, Little Barford’s three turbines went off because of steam over-pressures, likewise in an internal cascade, a result of the 3-phase being out of kilter
    – DNO’s turned off customers in orderly fashion – an event that occurs about once a decade
    – Rail power supply was not turned off anywhere (aside from some localised signalling systems of low materiality), but some modern trains and other railway equipment tripped out because of internal protection systems responding to frequency fluctuation. So this is apparently the railway’s own problem.

    Hornsea reckons its millisecond-level protection systems were set too sensitive, and it has adjusted them.

    One interesting thing I spotted is that Hornsea is nominally 1200MW but it is connected to an 800MW substation, so can only export 800MW. It was exporting at 799MW at the moment of the trip. That’s still a lot, when you think that we have about 22GW of wind capacity (excluding local embedded generation) and only briefly has the the wind generation on the system exceeded 10GW in the last few months. In the winter it would sometimes get up to about 12.5GW.

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