This meter is monitoring the power balance of the UK electricity grid. If the needle is too far to the left, it means more generation is needed to meet demand.
Would make a nice oscillating feedback system!
Grid frequency has nothing to do with demand. The National Grid frequency is a highly accurate 50.00Hz when averaged over 1 day - this fact used to be used for the old synchronous mains powered clocks we all used to have.
Real load/frequency data is available here
Cool.
I want this as a Vista Widget.
DThe message from Mogga contains these words:
I don't see why not. ISTR that the NG have an obligation to keep the average frequency to 50 Hz so there should be times when it reads high.
Ha! First time I looked it was close to 49.9. Just looked again and it was close to 50.1. Swings and roundabouts. :-)
You might not see much difference. The scale is not linear which makes it difficult to estimate where the legal limit is but my best guess is
49.5% which is a 1% deviation.On Sun, 2 Mar 2008 20:48:29 -0000, "Icky Thwacket" had this to say:
Used to have? I still have several :-)
The system frequency is the indicator of how well supply and demand has been matched on the grid. The national grid has a legal obligation to keep it between 49.5 and 50.5 Hz they try to keep it between 49.8 and
50.2 If the frequency was to drop below 49.5 mass blackouts would start as the grid tried to save it's self.
Grid frequency is on the right hand of the page. Matches the meter too!
In message , Icky Thwacket writes
Yep, it's for real. I've had it as a Favourite site for a couple of years now.
John
Frank Erskine formulated on Sunday :
Yes it does - the greater the load, the slower the generators run. The slower they run, the more input power is needed to increase their RPM until they reach the limit of their generating capacity - beyond that limit they must increase the number of generators on line.
That is correct, but they average it - they deliberately allow it to run faster than 50Hz when it has lost a few milliseconds to make the loss up. You can see that 'make up of time' if you watch the needle when it has run slow for a period. It isn't really an average over any particular time period, your mains synched clock will always be roughly about right and sometimes spot on - never should it be far from the correct time, unless power is lost completely.
Bob Eager brought next idea :
Fairly easy to resolve, if appliances only adjusted their demands slightly and incorporated some random level of damping of their adjustment.
Seems to be a very workable idea, your less essential appliances like washing machine heaters and immersion heaters easing back their demands when the grid is already overloaded.
It's been there for some time. However, most of that time it hasn't been working. (IIRC it said the kit had to be borrowed for something else and it was just displaying faked data). I don't see that warning anywhere now, so I presume it is working. I watchd it for a couple of minutes and it did track a change in frequency which a power meter also saw, although the exact values don't quite match.
Or shed some load.
The CEGB (& presumably todays motley crew of generating companies) had contracts with large industrial consumers for a cheap supply that they, the CEGB, could drop at short notice. The consumer might start up their stand by generator for a while, or stop using electricity in some processes (such as kiln drying) for a few hours.
DG
The frequency does appear to drop slightly at peak times and go over 50Hz at low demand times to make up. The actual tolerance is +/- 0.2Hz.
On Sun, 02 Mar 2008 23:30:09 GMT, Harry Bloomfield had this to say:
I never said that at all
They do anyway, as not only does the grid slow down, it also drops in voltage..
It does.
Thats beacuse they work VERY hard to keep it that way, adjusting the 'throttles' on the power stations.
On Sun, 02 Mar 2008 23:30:09 GMT someone who may be Harry Bloomfield wrote this:-
Indeed.
Reduction in frequency is also a good indication that some big plant somewhere has failed and left a big hole in the supply. As the remaining plant tries to supply the load so the frequency falls.
Fortunately this can be detected rapidly and automatically. When it happens there are a few places able to react fast enough to keep the lights on, the largest of which is Dinorwig
"Synchronised and spinning-in-air Emergency load pick-up rate from standby - 0 to 1,320 MW in 12 seconds"
That is four of the six sets, so presumably there are restrictions on trying this trick with all six sets.
Note that when in reserve the turbines are not consuming any water. There is some electricity needed to keep them turning, which can either be provided from another turbine or drawn from the external system. Rapid acting standby with little or no emissions.
Happens all the time. Emergency load shedding starts when the frequency drops too low - 47.5hz from memory!
If I'm repeating anything said by anyone else then apologies, problems withe Zen's news server dropping *lots* of articles!
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