Wind turbines and 3-phase power

[rcoe]

Hi all,

Hoping someone will be able to help me with a bit of confusion. I have been looking into wind turbines in a fairly unfocussed way. We seem to have a pretty ideal site with good predicted wind speed (although I would plan to put up an anemometer for a while before taking the plunge). One installer that I have discussed with says that the key "deal-breaker" is the status of our electricity connection to the grid. If it isn't 3-phase (according to him) then we could not install anything bigger than a 5kW turbine. I would be extremely surprised if we did have 3-phase power but he has said that some farms do have it if they had milking machines etc.
I have tried to get Scottish Power to tell me if I have 3-phase power but it doesn't seem to be possible.

Can anyone flesh out any detail on the issue of grid connection for larger turbines? And does anyone know how I would go about finding out whether I have a 3-phase connection or not?

Thanks very much,

Richard

[MKG]

Hi rcoe. It would have helped a bit if you'd told us what kind of building we're talking about - domestic, commercial, industrial, etc.

However, if it's domestic, I'd say the chances of you having a 3-phase supply are virtually nil.

Mike

EDIT: Your distribution board will look very different depending upon whether it's 3-phase or single phase. Basically, you'll have three live feeds or a single live feed (plus neutral). If you have 3-phase, please be careful. The voltage across any live feed to neutral is always 230/240 VAC. From phase to phase, though, it's nearer 400 VAC.

[rcoe]

Hi MKG thanks for your reply. We live in a farmhouse which has 2 outbuildings attached to it. To my highly untrained eye our board looks "normal" so like you I think the chances of there being 3-phase are nil.

[dave45]

At work our 3 phase supply has three separate meters, marked up with red, blue and yellow stickers. Different things are attached to each phase/meter.

[KathyLauren]

An easy way to see if you have three-phase power is to look up at the wires feeding the house. Typically, up the power pole you have some thin high-tension wires at the top, feeding a transformer (like a big metal bucket at the top of the pole), and some fat wires coming from that to the house.

If there is only one high-tension wire connected to the transformer, you have one-phase power. If there are three high-tension wires connected to the transformer, you have three-phase power. It would be really unusual for a house to have three-phase power. Even if the power lines outside are three-phase (there are three high-tension wires running from pole to pole), there is usually only one of them connected to each transformer.

[MKG]

Unfortunately, Keith, most mains supplies after sub-stations in the UK are underground. There's certainly a three-phase feed under the street somewhere (at least in a built-up area) such that block 1 is fed from phase 1, block two from phase two, and so on, to ensure phase balancing. And the local transformer is usually some distance away, hidden behind large fences. So the only clue most of us get is that distribution board. The social situation at the moment is that if anyone strung up a copper wire supply in the air, it wouldn't be two minutes before someone nicked it (they've even tried the aluminium high-tension cabling at the top of pylons )

See - life can be easier if you're stuck out in the wilds

Mike

[KathyLauren]

See - life can be easier if you're stuck out in the wilds

Sure is. :)

[The Riff-Raff Element]

See - life can be easier if you're stuck out in the wilds

Sure is. :)

That's why I do it, certainly.

I'm surprised Scottish Power can't tell you: for a start they'd normally be able to charge you more money for a three-phase supply

Are there no clues on the meter? A house we bought came with three-phase and the meter was specific for that and labelled as such. Tri-phase is not at all uncommon here.

[Green Aura]

Yes, we've got a 3-phase meter, not connected up to anything now, labelled as such. Our predecessor was a potter and used it for her big kiln. A lot of catering equipment runs off 3-phase too so if you know what your house etc was used for before it might give you a clue.

But I thought I'd read that 3-phase was cheaper for high consumption items, maybe not.

[The Riff-Raff Element]

But I thought I'd read that 3-phase was cheaper for high consumption items, maybe not.

The price per kWh is lower, often, but the standing charges are much higher. I think it makes sense for the heavy user, but not for us mere mortals