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1st Nov 2010, 7:31 pm | #1 |
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National grid frequency
After the thread on the grid here is an interesting site http://www.dynamicdemand.co.uk/grid.htm
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1st Nov 2010, 7:50 pm | #2 |
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Re: National grid frequency
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1st Nov 2010, 10:06 pm | #3 |
Dekatron
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Location: Kilmarnock, Ayrshire, UK.
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Re: National grid frequency
There seems to be a problem with the national grid site, every page reports an error. Dynamic Demand over the last few minutes reports a frequency nearly at 50.2hz, all very odd!
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1st Nov 2010, 11:22 pm | #4 |
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Re: National grid frequency
It's all working OK for me - Fireox 3.6.12
Alan |
2nd Nov 2010, 1:54 pm | #5 |
Dekatron
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Location: W.Butterwick, near Doncaster UK.
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Re: National grid frequency
all ok here.
David |
2nd Nov 2010, 3:42 pm | #6 |
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Location: Colne, Lancashire, UK.
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Re: National grid frequency
I've been watching that frequency meter on and off for the past month, it's funny watching it go up and down in relation to TV programmes...
I wouldn't mind having a real one though, something I could plug in and watch without having to use internet bandwidth, just cos I'm sad like that... |
2nd Nov 2010, 3:46 pm | #7 |
Nonode
Join Date: Mar 2010
Location: Dukinfield, Cheshire, UK.
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Re: National grid frequency
Given that we have lots of generating sites all over the country, and that we swap power with France, how are all those 50Hz generators kept in phase?
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Andy G1HBE. |
2nd Nov 2010, 4:00 pm | #8 |
Heptode
Join Date: May 2008
Location: Selby, North Yorkshire, UK.
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Re: National grid frequency
wow! do i not like that!? ive always known that specialists monitor the frequency to keep the grid balanced but never knew there was a website showing it!
Just watched it as a programme ended and there was indeed an increase in demand as the credits came up, but then it restored. Either the load planners are very good, or it was just a surge in people quickly channel hopping (didnt last long enough for kettle) |
2nd Nov 2010, 4:06 pm | #9 |
Dekatron
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Re: National grid frequency
By being connected to the grid! Any generator attempting to slip out-of-phase finds itself being dragged back again by the very power lines to which it is connected.
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2nd Nov 2010, 4:06 pm | #10 | |
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Re: National grid frequency
Quote:
Must be a fun job, sitting watching TV and then pressing a few buttons to adjust the supply... |
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2nd Nov 2010, 4:44 pm | #11 |
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Re: National grid frequency
If you want to watch the grid frequency, just get a frequency counter and connect it to the grid (e.g. a 12V secondary). You would need a counter which has a long gate time, so you can go down to 0.01Hz resolution. Or build a frequency multiplier or PLL so an ordinary RF counter can be used. Remember, the frequency is the same everywhere in the UK - except for those very rare occasions when the grid splits (and some Scottish islands?).
National Grid HQ is not that secret. It used to be in London near Bankside power station, and is now in Berkshire. They may do it differently now, but it used to be less important than the regional control centres. They try to predict 'TV pickups' etc. a day ahead so generation can be scheduled, and some power stations will be asked to regulate their output according to the mains frequency. If the frequency drops, they turn up the wick and generate a bit more power. At one time this would have been manual, but now computers do it. The link with France is DC, so there are inverters/synchronous rectifiers at each end of the link. We are not synchonised with the Continent. |
2nd Nov 2010, 5:29 pm | #12 | |
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Re: National grid frequency
Quote:
Are the powers-that-be still obliged to maintain frequency to be correct over a 24Hr period like they used to? When Willowholme power station was on the go at Carlisle, we visiting apprentices were shown a large clock above the control board (I think it had two seconds-hands) so that electric clocks would maintain a mean accuracy over the course of the day, and the power-station controllers could adjust their output accordingly.
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2nd Nov 2010, 5:56 pm | #13 | |
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Re: National grid frequency
Quote:
AFAIK the grid still maintains the correct number of cycles in each 24 hour period. I have a friend who works in grid control so I'll ask him when I next see him. He says that the guys on the front line, the actual controllers, are very highly paid but under enormous stress. |
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2nd Nov 2010, 6:52 pm | #14 |
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Re: National grid frequency
Hi
I think the link between France and the UK is DC so frequency changes on one side of "La Manche" won't affect t'other. Cheers, Pete Oops, I failed to spot the previous reference in post no.11, sorry.
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2nd Nov 2010, 7:05 pm | #15 |
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Re: National grid frequency
In the last hour I have got a large moving coil meter. Guess what for?
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2nd Nov 2010, 7:48 pm | #16 |
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Re: National grid frequency
Yes, I believe there are still supposed to be the right number of cycles in 24 hours, although I'm not sure what the accuracy has to be. There are limits on the permitted deviation from true 50Hz, and the accumulated error during the day.
I think the Leeds bunker was a bit more secret than others because it wasn't just for electricity. When I worked in the industry I got the impression that control centres were not secret but did like to keep a low profile, which is why I didn't say where in Berkshire the new HQ is. This sometimes backfired. The one in Manchester was in a housing estate and the locals believed rumours that it was a secret establishment for animal experiments, so the local oiks would throw stones and bottles over the wall and try to break the windows. Eventually they decided to invite the locals in and show them what really happened there. Better relations followed. |
3rd Nov 2010, 12:30 am | #17 |
Octode
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Location: Watford, Hertfordshire, UK.
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Re: National grid frequency
Might be fun to get my HP5370B hooked up, it has a display of 12 digits which should enable me to monitor the 50Hz down to pico seconds. It will do an automatic measurement of mean deviation over 100,000 samples. The counter never gets used for much so the exercise may do it some good though I suspect it will take some time for the natural quartz oscillator to settle down.
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3rd Nov 2010, 1:03 am | #18 |
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Re: National grid frequency
About 50 years ago, I was taken on a college outing to Battersea power station, and shown how an alternator was bought on line. This required the phase angle of the generator be compared to the National Grid frequency, and be reduced to zero, before being placed "on line." We were told serious mechanical damage would result from not complying with this procedure.
When umpteem million kettles are switched on, as "East Enders" finishes, quick start generators, such as pump storage and gas turbine stations are bought on line, so that voltage and frequency can be maintained. ALAN |
3rd Nov 2010, 1:23 pm | #19 |
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Re: National grid frequency
I have heard that you can get quite a loud bang if synchronising a bit late or early of the right spot - the grid gives the generator a good kicking!
The older gas turbine stations used for peak lopping are used as little as possible, as they are very expensive to run (they use jet fuel!). The new combined cycle gas turbines are much cheaper and used as base load sets, but can be less flexible than all the old coal-fired plant which is about to retire. One approaching problem is that much of the new generation coming on stream is either inflexible (CCGT, nuclear) or randomly variable (wind, solar). This makes frequency control rather difficult. I read recently that Germany has so much solar etc. that the variation might cause grid trips. We actually need a new generation of coal sets, but that now seems politically impossible. |
3rd Nov 2010, 2:39 pm | #20 | |
Hexode
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Location: Leeds, West Yorkshire, UK.
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Re: National grid frequency
[QUOTE=russell_w_b;376005]
Quote:
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