scoobra
Electrical
- Aug 18, 2003
- 1
I have a small industrial customer that would like to change from a solidly grounded to a high resistance grounded 480V service. They are presently served by a three phase wye-wye transformer, but do not have any phase to neutral loads. My initial thought was to change the transformer to a delta-wye, but I have to wonder if the existing transformer is also suitable. The 480V windings do not have reduced neutral insulation. The high and low voltage neutrals are tied together internally and brought out through a single bushing. I would tie the primary neutral to the grounded side of the NGR so that the fault current in the secondary would have a path in the primary(to balance the amp-turns). The transformer is a 1500 kVA, so the only protection will be high side fuses.
This is not a connection you typically see in articles, so I have some concern that there is something I am overlooking.
This is not a connection you typically see in articles, so I have some concern that there is something I am overlooking.