ECN Forum Forums General Topics of the Trade Non-US Electrical Systems & Trades New model transformer

I've noticed several new pole-mount transformers in my area of a type rather different to those we've been used to seeing over the years, so it looks as though the PoCo has switched to this type for replacements.

Can anyone identify the make?

Paul,

We've had xformers like that for quite a long time.

I'll see if i can get a picture of an old weather beaten one somewhere.

I think they're made by ABB.

...

They're used for remote small industrial 3-phase drops and also for providing power to small villages (bends in the road with a few houses, a pub, a police station and a post office)

paul or dave

is the transformer connection like delta primary and wye secondary ???


merci , marc

Marc,

Yes, it's 11kV delta primary, 240/415V wye secondary (or as this is a new xfmr, it may well be that the secondary is designed for the new nominal standard of 230/400V).

There is never a neutral on HV distribution lines in Britain, so all primaries are wired delta.

Paul,
Dave is in fact right about the brand of the transformer.
It is indeed an ABB Oil-filled 317 Series Distribution transformer.
We've actually got a few of these over here, used on Industrial sites.
Just a little note on the use of Star and Delta configurations in Distribution Systems, over here Star is used on the Primary winding in some places in the Network where the Transformer is required to be referenced to Earth.
The Earth is taken from the normal Star-point of the Transformer.

At school we were told 10 and 20kV distribution networks in Austria usually have a delta configuration, whereas systems with voltages exceeding 20kV (usually 110kV or 220kv) always have a star configuration. 230/400V supplies are usually star.

Presumably you mean that the originating windings on the higher voltages are wye (star) configuration but loads are still delta connected. If so, then I wonder if the lower-voltage lines are referenced to ground in any way.

The Cahier Technique paper on MV Distribution Systems has a table showing some of the grouding/neutral methods used, but doesn't include an entry for Austria.

Just an addendum to my original post.
It's interesting to see them spark gaps on the bushing insulators.
We don't use them here on our trannies for some wierd reason.
A very worth-while accessory in my opinion.
And there's more of that funny green wire.
BTW Paul, what is that wire heading downward at an angle from under the base of the transformer?.
It looks like a stay wire, but it's point of attachment looks too "flimsy" for it to be one.

Yes, it's a fairly common stay arrangement. You can't actually see the point of attachment in the first photo.

The part of the bracket just visible to the left of the xfmr is a loop through which the wire passes. It's anchored higher up the pole.

That arrangement is also fairly common in the States and Canada if I remember correctly. The general idea seems to be to allow the stay to be anchored into the ground closer than would otherwise be practical.