Skipweasel wrote:
In article o.uk,
says...
And how much stuff is about that can be switched off for an
indeterminate period without warning?


Fridge, freezer, washing machine etc. Even if they're only swapped to a
lower duty cycle - say ten minutes off in an hour, that may well be
enough to tide over the demand peak.

Heaters, immersion heater...... As long as it's not for much more than
an hour at a time.

Some of us are stuck in places without gas available.

--
Tciao for Now!

John.

Skipweasel wrote:

In article o.uk,
says...
And how much stuff is about that can be switched off for an
indeterminate period without warning?

Fridge, freezer, washing machine etc. Even if they're only swapped to a
lower duty cycle - say ten minutes off in an hour, that may well be
enough to tide over the demand peak.

Part of the logic behind smart meters is to permit this sort of
thing to happen. I have not yet seen any details of consumer
equipment designed with this in mind.

Considering how difficult it is to compare tariffs at the moment,
the future could well prove "interesting".

Chris
--
Chris J Dixon Nottingham UK


Have dancing shoes, will ceilidh.

On Fri, 11 Mar 2011 07:11:09 +0000, Chris J Dixon wrote:

Part of the logic behind smart meters is to permit this sort of thing to
happen. I have not yet seen any details of consumer equipment designed
with this in mind.

But for it to happen the devices being controlled need to be either
on their own controlled circuits (difficult, slow and thus expensive
to install) or via a box that the meter can communicate with to
switch the device on/off (not so difficult or slow to install but
higher capital).

Are the "smart meters" that the government said we were all going to
get in some ridiculously short time scale a few years back actually
meters that have this functionality or just ones with built in or
remote current power use display?

--
Cheers
Dave.

On Mar 11, 7:11*am, Chris J Dixon wrote:
Skipweasel wrote:
In article o.uk,
says...
And how much stuff is about that can be switched off for an
indeterminate period without warning?

Fridge, freezer, washing machine etc. Even if they're only swapped to a
lower duty cycle - say ten minutes off in an hour, that may well be
enough to tide over the demand peak.

Part of the logic behind smart meters is to permit this sort of
thing to happen. I have not yet seen any details of consumer
equipment designed with this in mind.

ISTR one of the RECs was handing out, or selling, smart fridges in a
trial a year or two ago.

MBQ

On Fri, 11 Mar 2011 02:39:24 -0800 (PST), Man at B&Q wrote:

ISTR one of the RECs was handing out, or selling, smart fridges in a
trial a year or two ago.

But fridges/freezers are not exactly a big load, say 100W and that is
on a pretty long duty cycle.

Fag packet figures:

20 million households - 20 million fridges, 10:1 duty ratio, 2
million at anyone time, 200MW from a UK demand of 50GW(ish). ****ing
in the wind.

A 5% voltage reduction saves more than 20 times as much power as
switching off 2 million fridges.

--
Cheers
Dave.

On Thu, 10 Mar 2011 17:09:04 +0000, The Other Mike wrote:

I'm not overly keen on this frequency based automatic load
shedding
(as in switching off) either. Sounds like a recipe for grid
instabilty if you ask me. Frequency drops, lots of stuff drops off
line, Whe Hey! too much capacity frequency goes up, stuff comes
back
online, frequency drops...

It doesn't work like that.

If the frequency drops then the first response is the governors on all
the generators on the system. They will always actively control the
energy input such that the frequency is maintained at the target of
50Hz.

snip

You miss the point. What you say about the current system of grid
control is true but we aren't talking about that we are talking about
autonomous boxes that switch things off based only on the frequency
of the supply.

I guess these autonomous boxes will have some form of randomisation
built in so they don't all switch stuff off at the same time (ie
within minutes of each other) and like wise don't switch back on at
the same time.

--
Cheers
Dave.

Dave Liquorice wrote:
On Fri, 11 Mar 2011 07:11:09 +0000, Chris J Dixon wrote:

Part of the logic behind smart meters is to permit this sort of thing to
happen. I have not yet seen any details of consumer equipment designed
with this in mind.

But for it to happen the devices being controlled need to be either
on their own controlled circuits (difficult, slow and thus expensive
to install) or via a box that the meter can communicate with to
switch the device on/off (not so difficult or slow to install but
higher capital).

Are the "smart meters" that the government said we were all going to
get in some ridiculously short time scale a few years back actually
meters that have this functionality or just ones with built in or
remote current power use display?

actually all the smart meters being talked about merely give you a
remote reading of instantaneous power consumption. Presumably you the go
around switching stuff off till it makes a difference.

In article o.uk, Dave
Liquorice writes

You miss the point. What you say about the current system of grid
control is true but we aren't talking about that we are talking about
autonomous boxes that switch things off based only on the frequency
of the supply.

Look at the Dynamic Demand link given elsewhere in the thread. This is
exactly what they are selling.

--
Mike Tomlinson

Mike Tomlinson wrote:
In article o.uk, Dave
Liquorice writes

You miss the point. What you say about the current system of grid
control is true but we aren't talking about that we are talking about
autonomous boxes that switch things off based only on the frequency
of the supply.

Look at the Dynamic Demand link given elsewhere in the thread. This is
exactly what they are selling.

Trouble is, it a crap business model.

Since no one saves any money by being kind to the grid..

Its just another desperate attempt to try and make renewables work
really, when everyone knows they basically don't.

On 11/03/2011 14:50, The Natural Philosopher wrote:
Mike Tomlinson wrote:
In article o.uk, Dave
Liquorice writes

You miss the point. What you say about the current system of grid
control is true but we aren't talking about that we are talking about
autonomous boxes that switch things off based only on the frequency
of the supply.

Look at the Dynamic Demand link given elsewhere in the thread. This is
exactly what they are selling.

Trouble is, it a crap business model.

Since no one saves any money by being kind to the grid..

Its just another desperate attempt to try and make renewables work
really, when everyone knows they basically don't.



Isn't that dynamic link thing the data you wanted in your "More fun with
power generation" thread?

Andy

Tabby writes:

240v is the target voltage, real voltage can be 10s of volts away from
this. 1v variation isn't an issue.

In fact, thanks to EU bureaucracy, isn't the target voltage now
230V +10% -6%, or some similar baloney which prevents any country from
actually having to change anything?

--
Windmill, Use t m i l l
@ O n e t e l
. c o m

Skipweasel writes:

the lights dim noticably in the house for a short time. It happens
fairly frequently in the early evening. It does not appear to cause
any problems to computers etc.
Nor should it - SMPS should be very tolerant of such things - after all,
they're usually considerably over rated in PC applications and only have
to up the duty-cycle briefly.

Especially when nowadays many are designed to work over a range of
input voltages from 100V to 260V without even changing a switch
position.

--
Windmill, Use t m i l l
@ O n e t e l
. c o m

In message , John
Rumm writes
On 11/03/2011 22:26, Windmill wrote:
writes:

240v is the target voltage, real voltage can be 10s of volts away from
this. 1v variation isn't an issue.

In fact, thanks to EU bureaucracy, isn't the target voltage now
230V +10% -6%, or some similar baloney which prevents any country from
actually having to change anything?

Yup.

But have we not adopted 230V for new installations or when substations
are tweaked or replaced? My mains seems to hover 5 to 10V lower than the
240V of many years ago, when it sometimes reached 255V*. It's presently
236V (at 8:15am on a Saturday morning).
*Over 270V on a couple of occasions, but that's another story.
--
Ian

On Fri, 11 Mar 2011 22:26:13 GMT, Windmill wrote:

In fact, thanks to EU bureaucracy, isn't the target voltage now
230V +10% -6%, or some similar baloney which prevents any country from
actually having to change anything?

It doesn't *prevent* any country changing anything, it just means
they don't *have* to change anything.

It was going to alter again to 230 +/- 10% but that puts the lower
limit down to 207 and a nearly 50v range. Starting to get hard to
build kit that will work satisfactorily at the lower end and not blow
up at the upper. That proposed change seems to have been quietly
dropped. B-)

--
Cheers
Dave.

In message , John
Rumm writes
On 12/03/2011 08:16, Ian Jackson wrote:
In message , John
Rumm writes
On 11/03/2011 22:26, Windmill wrote:
writes:

240v is the target voltage, real voltage can be 10s of volts away from
this. 1v variation isn't an issue.

In fact, thanks to EU bureaucracy, isn't the target voltage now
230V +10% -6%, or some similar baloney which prevents any country from
actually having to change anything?

Yup.

But have we not adopted 230V for new installations or when substations
are tweaked or replaced? My mains seems to hover 5 to 10V lower than the

Not as far as I am aware. The aim is still to supply at 240V. However
that does not mean everywhere will see that.

As the European voltage has been long-since normalised at 230V, I can't
see why the target should be 240V.

That said, with the ever-increasing use of switchmode power supplies,
there is possibly a slight advantage in supplying the highest possible
voltage as this minimises the amount of current drawn, and hence
minimises the power loss and voltage drop on the power cables.
--
Ian

On Sat, 12 Mar 2011 08:16:37 +0000, Ian Jackson wrote:

In message , John
Rumm writes
On 11/03/2011 22:26, Windmill wrote:
writes:

240v is the target voltage, real voltage can be 10s of volts away from
this. 1v variation isn't an issue.

In fact, thanks to EU bureaucracy, isn't the target voltage now
230V +10% -6%, or some similar baloney which prevents any country from
actually having to change anything?

Yup.

But have we not adopted 230V for new installations or when substations
are tweaked or replaced?

No, why should there be? The limits are set at +10% -6%. Finito.

My mains seems to hover 5 to 10V lower than the
240V of many years ago, when it sometimes reached 255V*. It's presently
236V (at 8:15am on a Saturday morning).
*Over 270V on a couple of occasions, but that's another story.

Such variations occur because of the automatic voltage control used with
system transformers. These can change taps on line to increase or decrease
the volts on the 11kv busbars depending on load.

Distribution transformers OTOH have a fixed tapping range of ±5%, 2.5% and
0% of nominal input voltage. The transformer will be tapped for a best
estimate of the nominal operating voltage at that point on the circuit.

However, that voltage will vary depending on the load, as well as whether
or not any load shedding is taking place.

As far as I know, there has been no widespread revisiting of voltage
gradients since the move to European harmonisation, so UK transformers will
ideally be pushing out 245 volts or thereabouts,± about 10 volts depending
on load, or much less if there are voltage reductions in place for load
shedding.

Any further speculation about why your volts are varying is just that,
speculation.

--
The Wanderer

Trying to extract useful information from the Internet
is like trying to sip from a firehose.

John Rumm wrote:
On 13/03/2011 09:51, Ian Jackson wrote:
In message , John
Rumm writes
On 12/03/2011 08:16, Ian Jackson wrote:
In message , John
Rumm writes
On 11/03/2011 22:26, Windmill wrote:
writes:

240v is the target voltage, real voltage can be 10s of volts away
from
this. 1v variation isn't an issue.

In fact, thanks to EU bureaucracy, isn't the target voltage now
230V +10% -6%, or some similar baloney which prevents any country
from
actually having to change anything?

Yup.

But have we not adopted 230V for new installations or when substations
are tweaked or replaced? My mains seems to hover 5 to 10V lower than
the

Not as far as I am aware. The aim is still to supply at 240V. However
that does not mean everywhere will see that.

As the European voltage has been long-since normalised at 230V, I can't
see why the target should be 240V.

Only that is what we have always done, and that is what the equipment we
have is designed to do. So it makes little sense to change anything
since what we do is already within spec.


...cos the spec was bent to fit us in..


BUT I suspect *new* installations are 230V.

I've not ever bothered to stick a meter on mine..

On Sun, 13 Mar 2011 22:38:37 +0000, The Natural Philosopher wrote:

John Rumm wrote:
On 13/03/2011 09:51, Ian Jackson wrote:
As the European voltage has been long-since normalised at 230V, I can't
see why the target should be 240V.

Only that is what we have always done, and that is what the equipment we
have is designed to do. So it makes little sense to change anything
since what we do is already within spec.


..cos the spec was bent to fit us in..

No it wasn't. That spec applies to the UK only.

Other parts of the EU started with a nominal voltage of 220v. A different
spec applies in those parts of the EU.

What *everyone* keeps overlooking when pontificating about supply voltage
and what it should be, when the harmonisation was brought in, the emphasis
shifted to appliance manufacturers. An EU directive requires that all new
appliances will operate across the range of voltages to be found in Europe.


BUT I suspect *new* installations are 230V.

I don't think so. What point would there be when the limits are (to all
intents and purposes) permanently set at +10%?

I do wish people would check the facts before spouting half-thought-through
ideas.

--
The Wanderer

I may be stupid, but I don't have to prove it!

On Mar 11, 12:06*pm, "Dave Liquorice"
wrote:
On Fri, 11 Mar 2011 02:39:24 -0800 (PST), Man at B&Q wrote:
ISTR one of the RECs was handing out, or selling, smart fridges in a
trial a year or two ago.

But fridges/freezers are not exactly a big load, say 100W and that is
on a pretty long duty cycle.

It's probably very good PR, however.

MBQ

On Fri, 11 Mar 2011 12:17:41 +0000 (GMT), "Dave Liquorice"
wrote:

You miss the point. What you say about the current system of grid
control is true but we aren't talking about that we are talking about
autonomous boxes that switch things off based only on the frequency
of the supply.

They will be individually addressable, not fully autonomous. Similar
to radio switching of economy 7 loads. They might address on a block
basis say 10% of demand which can be spread across the country, or
they can do it by area to reduce the potential for overload on
specific underground cables / overhead lines/ transformers

It's only an extension of what is done on many industrial supplies
today to limit demand - that is actively managed on an individual
supply basis and has been for a number of years. The only change is
extending the intelligence from the 'meter' / to the appliance


--