Posted by Ken on April 6, 2009, 8:28 pm
On Sun, 05 Apr 2009 23:25:09 +0100, Eeyore
> > > > >> In alt.energy.renewable Eeyore twisted the electrons to say:
> > > > >>>> Actually it wouldn't be "them" switching your appliances on/off,
your
> > > > >>>> appliances would do it automatically based on their own state and
the
> > > > >>>> condition of the national grid. I haven't found conclusive proof
as yet,
> > > > >>>> but it seems that fridges with this sort of dynamic demand are now
being
> > > > >>>> sold in the UK ...
> > > > >>> I'd like to know where they get their data from.
> > > > >> It monitors the mains frequency ...
> > > > >
> > > > > The mains frequency is very rock solid. It HAS to be for the grid to
work. You're
> > > > > talking crap.
> > > > >
> > > > The instantaneous mains frequency isn't rock solid. The control system
> > > > keeps the long term *average* mains frequency rock solid so that
> > > > synchronous electric clocks stay in time, In the short term the
> > > > frequency drifts by anything up to a Hz or so.
> > >
> > > Utter nonsense. Except in 3rd world countries maybe.
> >
> > In Europe.
>
> I suggest you look up the regulations. You're talking out of your arse.
No. I know the real life.
Posted by Neon John on April 6, 2009, 12:03 am
On Mon, 06 Apr 2009 00:21:20 +0100, Tim Jackson
>Alistair Gunn posted in this thread that the UK statutory requirement is
>plus or minus half a Hz, I didn't know that when I posted earlier, I
>just knew from observations that it fluctuates over a range of something
>approaching 1Hz over minutes under heavy load conditions, eg over the
>notorious "tea-break" load spike. Or it did several years ago when I
>made those observations.
>If you don't believe me go stick a frequency meter on your domestic
>supply and see where it's at. IIRC most of the time it was +/- 0.1Hz or
>so, with occasional larger excursions.
Why do you keep posting about England, a place barely the size of a
large state here, in what is mostly a US newsgroup. It is irrelevant
to what happens here.
For reasons that you should understand having to do with wide area
network stability, the frequency here is dead on within a fraction of
a cycle all the time. The nuclear power plant where I "grew up"
(first 10 years of my career) had a large frequency recorder with a 12
inch wide chart. 60 hz was in the center of the chart and the
deviation on either side was 0.5 hz. I never saw the pen move more
than a few pen widths off 60 hz.
Another data point. I have a Dranetz power quality monitor connected
to my service that runs continuously. I have the frequency alarm set
to alert at 1 tenth of a cycle variance from 60.00 hz. It has never
alarmed in over 10 years of constant operation.
In order to deviate from 60.00 cycles, a utility would have to isolate
itself from the grid (or else be lucky enough to have an HVDC feed).
That has happened in the past in NY and CA but I doubt that it would
now, what with the new FERC reliability rules in effect and the
ability to wheel power hither and yon.
If it is acceptable for the British power industry to drop a whole
cycle then frankly, someone needs to be shot! And a few more nuclear
power plants built.
John
Posted by Eeyore on April 6, 2009, 2:17 am
Neon John wrote:
> On Mon, 06 Apr 2009 00:21:20 +0100, Tim Jackson
> >Alistair Gunn posted in this thread that the UK statutory requirement is
> >plus or minus half a Hz, I didn't know that when I posted earlier, I
> >just knew from observations that it fluctuates over a range of something
> >approaching 1Hz over minutes under heavy load conditions, eg over the
> >notorious "tea-break" load spike. Or it did several years ago when I
> >made those observations.
> >
> >If you don't believe me go stick a frequency meter on your domestic
> >supply and see where it's at. IIRC most of the time it was +/- 0.1Hz or
> >so, with occasional larger excursions.
> Why do you keep posting about England, a place barely the size of a
> large state here, in what is mostly a US newsgroup. It is irrelevant
> to what happens here.
Britain ( not England ) is also tied to the European grid which is every bit
as large as your own.
> For reasons that you should understand having to do with wide area
> network stability, the frequency here is dead on within a fraction of
> a cycle all the time. The nuclear power plant where I "grew up"
> (first 10 years of my career) had a large frequency recorder with a 12
> inch wide chart. 60 hz was in the center of the chart and the
> deviation on either side was 0.5 hz. I never saw the pen move more
> than a few pen widths off 60 hz.
> Another data point. I have a Dranetz power quality monitor connected
> to my service that runs continuously. I have the frequency alarm set
> to alert at 1 tenth of a cycle variance from 60.00 hz. It has never
> alarmed in over 10 years of constant operation.
> In order to deviate from 60.00 cycles, a utility would have to isolate
> itself from the grid (or else be lucky enough to have an HVDC feed).
> That has happened in the past in NY and CA but I doubt that it would
> now, what with the new FERC reliability rules in effect and the
> ability to wheel power hither and yon.
> If it is acceptable for the British power industry to drop a whole
> cycle then frankly, someone needs to be shot! And a few more nuclear
> power plants built.
It doesn't happen. Anyone who thinks it's 49-51 Hz is an IDIOT. As you say,
it would cause disastrous consequences to the interlinking of various
generation plants.
Graham
Posted by Ken on April 6, 2009, 8:39 pm
On Mon, 06 Apr 2009 03:17:26 +0100, Eeyore
> Anyone who thinks it's 49-51 Hz is an IDIOT.
We don't think, we know.
Check it out in practice and you will see.
Now in the night at 22:31 I have 50.10 Hz here in Sweden.
Posted by Eeyore on April 7, 2009, 2:04 am
Ken wrote:
> > Anyone who thinks it's 49-51 Hz is an IDIOT.
> We don't think, we know.
> Check it out in practice and you will see.
> Now in the night at 22:31 I have 50.10 Hz here in Sweden.
But NOT 51 Hz.
Graham
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> > > > >>>> Actually it wouldn't be "them" switching your appliances on/off,