ECN Forum Forums General Topics of the Trade Non-US Electrical Systems & Trades Norwegian power?

DSK, I think you will like this very interesting:

http://assets.fluke.com/manuals/1654bit_iseng0000.pdf

Great link, thank you.

Why IT? When I asked som 30 years ago, they claimed it to be safer. We should modernize a system from 1940 (IT) and the supplier would change the transformer at the same time, we offered to pay the extra cost to change to 400V TN-S or TN-C-S
but they refused "of safety reasons".

Blessed are the meek,
For they shall inherit the earth. !

Welcome



I agree it safer, personally short the nullpunkt sikring ( http://www.el-tjeneste.no/files/Brosjyre-Nullpunktsikring.pdf ) and run a PE from the transformer N to all homes and you have the safest system.

Shame some are taking TN-C-S

Some pictures of new vs. old transformer in the Lillehammer area.

Thank you!

What connection are the transformers?

Are those boxes on the LV fuses?

Right, And a nice lady at eidsivaenergi.no will send us data about the transformers. This looks to turn out well for the forum.

dsk

Generally, the primary side (HV) will be Delta connected, the Secondary side (LV) will be Star connected.
By the looks of things, the two black boxes on the left pole are triple pole LV fuse-switches, when you open them up, it cuts power to the load side of the fuses.
The HV side is fused by DDO type expulsion fuses seen on that intermediate cross-arm as part of the vertical air-break switch.

Thanks! Id be very interested in the windings and data plate.

If you zoom on this picture: http://commons.wikimedia.org/wiki/File:Three-phase_distribution_transformator_IMG_8086_Hurum_Norway_23kV_240V.JPG

The data plate says Yyn0.

Which would come out as ungrounded wye primary with a wye secondary neutral brought out.

Now that I think about it, if the primary is wound wye, wouldn't it be so it can be solidly grounded? What would the IEC designation be for that?

I see what looks like a forth ground/neutral wire on the MV, so it would make sense then.

A primary grounded wye has the advantage of being resistant to ferroresonance, which Id imagine is more of a concern at 22kv and a long run.

Unless the primary is ungrounded wye? If ungrounded, than why wye and not delta? An ungrounded wye with a shorted secondary nullpunkt and one 230 volt phase faulted would make for some very interesting conditions.

Very interesting.

It has been extremely silent from eidsivaenergi.no so far.

dsk

Its ok, things take time