347/600V generator connected to a 600V delta transformer

[hattrick72]

Good day all,

I have a 347/600V generator and I will be connecting it to a 600V/208V delta to wye transformer. I do not know what random loads are going to be connected to the transformer so I must assume I will end up with some unbalanced phases. Is it perfectly okay to connect only my phases to the transformer and leave my neutral floating, or should I tie the neutral within my generator to the generator ground. The secondary of my transformer will have a neutral to ground bond with my main electrode in the vicinity of my transformer secondary. I will not be installing any other electrode in the system and I will also have a bond connecting to every panel board the system supplies. (This is a temporary set-up for a field exercise)

If I leave the neutral floating I will run a bond from my gen container to the transformer.

If I bond my neutral to ground at the generator I will be installing an electrode at the generator and bond my two electrodes together.

Preferably I will be able to rewire my generator 600V delta and only have to bond my generator container to my transformer container. (It is a Cummins so I may need a different pt/ct card in which case we won't be buying one and scraping the rewiring also I'm not quite sure if I need a computer program to tell the controller to expect a delta output rather than a wye etc.)

What would you suggest and is there anything above that is an incorrect method ie. bad grounding practice.

Appreciate all insight.

 

[GoldDigger]

If you do not ground the neutral of your generator you would have to incorporate ground detection and the generator manufacturer may not allow floating operation.
As long as you use a delta primary, there is no reason not to leave the generator wired as a wye source, AFAIK.
Imbalance in your wye loads on the secondary will not map directly to the same ratio imbalance in your generator wye windings, but that should not make any imbalance worse or harder to manage.

Tapatalk!

 

[hattrick72]

Great thank you. CT over the neutral to bond connection in the transformer wired into a ground fault relay that can be set to shut the generator down at a set current should suffice? Or is there a more appropriate location for the GFR

 

[GoldDigger]

Depends on whether you want direct ground current detection or non-zero sum current in the three phases plus neutral.

Tapatalk!