Voltage spikes

[Skipweasel]

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.

[John Williamson]

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.

[Chris J Dixon]

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

[Dave Liquorice]

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?

[Man at B&Q]

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

MBQ

[Dave Liquorice]

shedding

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.

[The Natural Philosopher]

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.

[Mike Tomlinson]

In article , Dave Liquorice writes

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

[The Natural Philosopher]

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.

[Andy Champ]

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

Andy

[Windmill]

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]

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

[John Rumm]

Yup.

[Ian Jackson]

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.

[Dave Liquorice]

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-)

[John Rumm]

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

[Ian Jackson]

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.

[The Wanderer]

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

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.

[John Rumm]

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.

[The Natural Philosopher]

..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..