So what did happen on Friday?

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So what did happen on Friday?

Postby Suff » 15 Aug 2019, 22:51

Not entirely sure as to the ins and out's but the short version is that one power station in Cambridge had to emergency shutdown and one wind farm, at approximately 8 times the capacity (max rated power), disconnected from the grid in response. It caused emergency brown out safeties to kick in and shut down chunks of the grid.

That, supposedly, 6gw wind farm should have been kicking out around 3-4gw of power. Or, in other words, about the power of the largest coal fired power lant in it's heyday burning coal.

The immediate impact I noticed was an article in this is money claiming that by 2040 these power outages would become common if we radically ramped up plug in electric vehicles to the levels seen in Norway.

Someone, somewhere, needs a kick up the jacksie. My thoughts? Wind farms were integrated into the grid with their nameplate power (max theoretical power), with the safety systems based on that nameplate power. The problem is that Nuclear power stations hit about 95% of their nameplate power, coal around 90% and wind somewhere between 0% and 60%, with offshore wind averaging around 45%.

My suspicions are that the power station shutdown in Cambridge triggered a demand for the 6GW rating on the wind farm. The wind farm couldn't deliver and the resulting loss in frequency forced it to disconnect in self defence.

Somebody, somewhere, is going to have to fess up that wind farms which cost half as much as a nuclear power station and can be delivered in half the time, but have a rating twice as high as the nuclear station, are actually producing half of the equivalent nuclear power station output most of the time.

That is going to cause some ruckus because I believe that the only way we'll actually fix the problems is to admit that the wind farms are actually inputting far less power into the grid than we are being told. Only then will they be able to plan for it correctly and report to the Government what needs to be done.

Queue huge amounts of screaming and stamping and gnashing of teeth.

The very first look at the system logs showed that we dodged the blackout bullet 3 times in the last 2 months before the disaster finally struck on the 4th event.
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Re: So what did happen on Friday?

Postby Workingman » 16 Aug 2019, 16:32

The way I understood things it was a combination of two failures in the system within two minutes of each other - a huge coincidence.

The first was at the gas-fired plant at Little Barford. This set off the call for reserve and flexible generation capacity to respond, however, as that was going on, Hornsea off-shore field suffered a transmission failure creating further emergency response requests.

The combination left the system with a shortfall of about 2GW and that triggered a drop in frequency to 48.9Hz. The emergency responses, including battery back-up, were not sufficient or in time and so NG had to ask local providers to start cutting services to customers. This, then, created an opposing frequency spike and a load-balancing problem that took about 45 mins to even out.

From the outside looking in it appears that the initial auto responder requests created a series of knee-jerk reactions with other auto responders within the system and it took human "hands on" to resolve things, hence the government inquiry into the handling of what looks like an emergency disaster that could have been avoided.
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Re: So what did happen on Friday?

Postby TheOstrich » 16 Aug 2019, 17:54

I have seen it said that the Little Barford incident was actually as a result of a lightning strike somewhere on the grid close by, and the shut-down was an automatic defense response.

Also of interest is the fiasco of the new Siemens Class 717 electric multiple units brought to a standstill on the lines north of London. It's said over a dozen of these stranded trains could not be restarted when power was restored, and each needed the attentions of a fitter. No wonder the rail network was in chaos!
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Re: So what did happen on Friday?

Postby Suff » 16 Aug 2019, 21:40

The Hornsea farm was operating at 800mw for a rated power of 6gw.

Bets that the initial response to little Barford was a demand for another 800mw from the local, 6gw rated, generating station and the defence mechanism for Hornsea was to take itself offline totally.

The outages were designed to avoid a cascade failure and they reacted as expected. But the Hornsea disconnect turned a crisis into a disaster.

Recognition is slowly setting in that replacing our Coal power with part time wind and solar is making the grid significantly more fragile.

More Nuclear needed urgently.

The problem?

The very people who want to remove Coal are the most vociferous in demanding we remove our Nuclear power....

Stupid is as stupid does..
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