Power factor and domestic electricity billing in the UK?

Can someone confirm that power factor is NOT taken into consideration for domestic supplies? I have a feeling it isn't, but I can't find any information on the internet. If it matters, it's a modern (<5 years old) electronic meter I have. The power factor in my house is an average of 0.7 so depending if it's charged for or not, my bill could be completely different.
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On 17/04/2014 01:07, Uncle Peter wrote:

Domestic meters only record real power...
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The very fact that you pay for kilowatt hours (Kwh) not kilovoltamps hours (Kvah) tells you that power factor is not accounted for. Only commercial organisations might be asked to pay for Kvah.
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So how does this affect actual loading of the system. Is it large enough for them to really be losing out? I can remember that when I worked in a factory, the leccy board came around and wanted to redistribute the soak test racks and other things to different mains phases due to imbalance of power factor due to the method the ssets used to get power. It always made me wonder how, if this was so bad, why it made no difference when they wer in peoples homes. Brian
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On 17/04/2014 09:41, Brian Gaff wrote:

For industrial users, certainly...

Domestic users are far less likely to have a PF significantly below unity, and if they do, it tends to be down to harmonic content rather than classical voltage current phase mismatch.
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I know they call it kWh, but that doesn't mean that's what they charge for :-)
I wanted to make sure that what my own meters read was the same as what theirs does. My own meters show power factor, but I think the price they show is not based on that reading. It's not clear though, as one of them (newer version of the same model!!) shows kW as kW, but the other shows kW when it's actually reading kVA. For example, one might read 240V, 2A, 480W, PF 0.7. The other will read 240V, 2A, 336W, PF 0.7. I think when I watched the costs going up on the counters, they both seemed to be calculating cost from VxAxPF, despite what was shown as "kW".
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I would imagine that in a street, the substation is even loaded as there are several houses on each phase. Also capacitive loads and inductive loads probably even out too. But the square-wave-creating switched mode power supplies cannot be evened out, so I guess that's costing them in losses in wires.

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On Thu, 17 Apr 2014 08:38:27 +0100, harryagain wrote:

At work (25 years ago) we paid for kWh but were charged for MD (Maximum Demand) peak on kVA (not kVAh). Much correcting of PF went on; especially as, being design and manufacture of electronic assemblies, the load was mostly fluorescent lighting and not a lot of inductive load.
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The power factor is the ratio between true power (Watts) and Apparent power (Volts x Amps) The current lags the volts in inductuve equipment. The power factor is also the cosine of the angle between volts and amps. So angle = 0, cos 0=1 (ie in phase, (resistive load) Power factor is 1/unity.
angle = 90, cos 90 = 0 (pure inductive load) Nor actually achievable in practice.
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On 17/04/2014 18:25, harryagain wrote:

True, but not usually that applicable to non unity domestic loads in this day and age...
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On Thursday, 17 April 2014 01:07:25 UTC+1, Uncle Peter wrote:

domestic supplies? I have a feeling it isn't, but I can't find any inform ation on the internet. If it matters, it's a modern (<5 years old) electro nic meter I have. The power factor in my house is an average of 0.7 so dep ending if it's charged for or not, my bill could be completely different.
That depends on what you think you mean by your first sentence.
Domestic meters work with true watts, not volt-amperes. AFAIR, they all ex plicitly indicate that they measure kWh. There is no charge for having a b ad power factor; you can take as many amps as you want at no cost, providin g that your current and voltage waveforms are orthogonal. Except in princi ple that the amps must not be more than the supply rating and in practice t hat the amps must not blow the fuse. And if they ever find that you are do ing something intentionally unreasonable, they'll make sure that you suffer for it, somehow.
If you have Economy 7 or Economy 10, and use that to control storage or imm ersion heaters, your power factor will improve while the heaters are active .
The supplier will not care about your domestic power factor as such; it is the total reactive volt-amperes that you take which might concern them.
Your non-zero power factor is *most* unlikely to be compensated by opposing contributions from neighbours. But the actual supplier (the operator of t he street wires and transformers) will know the likely overall power factor of a residential street, and can fit compensating reactances if beneficial enough.
Your single-phase supply will of course be an unbalanced load contribution for the street's three-phase supply; but your neighbours on different phase s will on average restore the balance sufficiently.
For businesses of sufficient size, both power and power factor can be taken into account in derermining the electricity bill, and/or a business can be compelled or persuaded to improve its power factor.
You might consider searching http://www.legislation.gov.uk for "kilowatt ho ur" or similar, etc.
I write as one who for some years was concerned with the non-domestic measu rement of UK AC power.
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Volts x Amps x power factor IS watts by definition.
Power factor IS the ratio between watts and VoltsxAmps.
Watts/voltsxamps = Power Factor.
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But an old coin meter installed by the husband of a relative in the boarding house he used to run charged for an inductive load. Quite generously.
As I found out on a trip back to Scotland while still living in Canada.
I had plugged in a 3.5 KW autotransformer (needed 'cos I planned to use 110V power tools as soon as tenants left a flat which I'd rented out).
With no transformer load to speak of, the meter needed repeated feeding!
It now has a 10uF 250VAC capacitor to correct the power factor (also stops it from tripping MCBs during power on).
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I worked in a school which had a capacitor bank. Not sure why, I can't see most of their loads being inductive. Maybe it was from back when they had inductive ballasts on the lighting. Probably nobody thought to check if it's still set right.
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Thanks, that's the answer I was looking for. Although does that also apply when taking power off the peaks of the waveform for shitty switch mode supplies?

Nope, gas. Although I rarely use it.

Maybe not, I use a lot more power than most. Can phases cross over with substations? Or is each one seperate right back to the power station? What I mean is.... is there such a thing as a transformer which takes 3 phases in the primary, and gives three phases in the secondary, but you can draw more from one phase on the output and put more in on a different phase on the input?
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Yes, I know. So one of my meters is incorrect (I think it's just the kW display is actually showing kVA, calculating the cost seems correct - based on kW, not kVA). This one: 240V, 2A, 480W, PF 0.7.
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wrote:

There are both three phase and single phase transformers. Large load usually have three phases in order to distribut the load equally over the phases as far as is possible.
The high voltage side is isolated from the low voltage side.
The naming/colouring of the phases is purely arbitary, only the "rotation" of the phases is important.
If a load is unbalanced (ie not equally distrtributed between the phases, it results in both phase shifts and unequal voltages appearing between phases.
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Yes. They generate 3rd-harmonic distortion, which can be bad in large quantities because it adds together in the neutral line, rather than canceling out between phases.

The final step-down transformer is a delta-star configuration, as there are no neutral conductors in the supply network until you step down to 240V. A high load on one of the 240V phases becomes a not so high load on two of the three phases supplying the final stepdown transformer, so you can see that your one-phase load is already being smoothed as you work back up the supply chain.
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On 18/04/14 10:44, Andrew Gabriel wrote:

Not here it ain't. Nor any of the pole mounted transformers on the local 11KV overheads. One phase partial deltas.
Star-delta is not a configurations that exists in the real world either. Its one or the other.
Its hard to see how you can supply a single phase from three phases anyway. A single phase is always the result of the difference between two phases.
You cant extract a single phase from a star connection anyway. A star connected load implicitly is a three phase load.
as there

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And I guess there's no way to cancel a harmonic like you can shift normal PF with a capacitor.

I see. So the only problem of uneven phase loading is locally.
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