Ideal electrical systems (just idle curiosity)

[The Natural Philosopher]

so far so good

and, if

Yep a couple of hundred megahertz is what we transmit power at these days!

[harryagain]

The loss arises from energy taken to reverse the magnetic field.

[John Williamson]

It can seriously affect stuff as low as 455kHz, if you remember the Litz wire we had to use for IF transformers in AM radios back in the day.

The thicker the conductor, the stronger the effect, and it is even noticeable at 20kHZ, according to this site:-

Not noticeable in the special case we're discussing here, but I did say "if the frequency is high enough" in the general case.

[John Williamson]

I just said that.

[John Williamson]

Not in copper or aluminium wires.

[tony sayer]

Yep water -v- air cooled;)...

[Tim Watts]

A normal armoured cable would have a pretty effective faraday screen around the live cores.

Not sure about mega HV cables but I'd be surprised if they were not fully screened too.

[Tim Watts]

So I wonder who regulated the frequency?

And what happens if one end starts to "wobble" (phase angle oscillation)? Do they just island the country.

[Andy Wade]

I'd vote for the standard domestic supply being 3x32 A (3-ph) instead of

1x100 A. Then we'd have the advantages of 3-phase for motors and rectification, and could have 400 V appliances like cookers and showers hooked-up with 2.5 or 4 mm^2 cables. Proposals now required for a compact 5-pin 16 A plug & socket...

[damduck-egg]

Germany Austria and Switzerland also operate another interconnected network at 16.7Hz which is what most of their electrified railways use. The lower frequency suited the simple motors and control available when the systems were first introduced in the early part of the 20th century.

G.Harman

[harryagain]

Any magnetic field takes energy to establish or reverse it. Magnetic fields are associated with any electric current.

[harryagain]

There's nothing stopping you having that now. The range of appliances available might be a bit limited to you.

[harryagain]

No that's incorrect. Higher frequency = smaller physical sized motors & transformers but greater losses. Aircraft run on high frequency power to save weight.

[Tim Watts]

I agree...

If you look at a commando plug/socket, the pins are well built but not that much heavier than a 15A round pin plug.

So I do not see why you could not make a 3 phase version of a 15A plug that fitted in at least a double backbox.

[meow2222]

HF smpsu transformers have much lower copper losses & total losses than 50Hz iron lumps.

NT

[The Natural Philosopher]

Actually they don't.

[meow2222]

They surely do. Why do you say they dont?

NT

[Theo Markettos]

It would also be more difficult to use such cables for tying people up, or as a garotte. But then they're more useful as a cosh. It's a tricky one, this H&S lark...

Theo

[newshound]

If you watch footage of repairs to 400 kV overhead lines (typically shot from helicopters) you will see long and impressive arcs being drawn from these for several seconds while they are brought down to earth potential.

[John Williamson]

That's not what it says in the article you referred us to.