"The Natural Philosopher" wrote in message
...
On 18/04/14 10:44, Andrew Gabriel wrote:
In article ,
"Uncle Peter" writes:
On Thu, 17 Apr 2014 18:31:28 +0100, wrote:

On Thursday, 17 April 2014 01:07:25 UTC+1, Uncle Peter wrote:
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.

That depends on what you think you mean by your first sentence.

Domestic meters work with true watts, not volt-amperes. AFAIR, they
all explicitly indicate that they measure kWh. There is no charge for
having a bad power factor; you can take as many amps as you want at no
cost, providing that your current and voltage waveforms are orthogonal.
Except in principle that the amps must not be more than the supply
rating and in practice that the amps must not blow the fuse. And if
they ever find that you are doing something intentionally unreasonable,
they'll make sure that you suffer for it, somehow.

Thanks, that's the answer I was looking for. Although does that also
apply when taking power off the peaks of the waveform for ****ty switch
mode supplies?

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.

If you have Economy 7 or Economy 10, and use that to control storage or
immersion heaters, your power factor will improve while the heaters are
active.

Nope, gas. Although I rarely use it.

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 the 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 phases will on average restore the balance sufficiently.

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?

The final step-down transformer is a delta-star configuration,

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.


All our three phase transformers in the UK reducing from medium/high to low
voltage are star delta configuration.
The primary winding is delta (or mesh) and the secondary winding is star.

The only exceptions are for special purposes,