Transformer Ho (neutral) connection

[huntr52]

this may not be the best place to ask, but I'll start here!

We are having a new 2000kVA, 25kv/480-277, Y-Y transformer installed on an oil & gas site with both Xo and Ho bushings. Can someone comment on any codes or general practices about whether we should have the utility bring a neutral to the Ho?

At this point there may be some filtering systems installed on some small VFDs but I dont know for sure as I havent seen those onelines or bills of materials.

I dont know if there will be a need for this connection but am hoping someone can comment as stated on code requirementl for this connection, general practice or operational experience.

:dunce:

 

[augie47]

You might find this thread interesting
http://forums.mikeholt.com/showthread.php?t=52621&highlight=wye+wye+connection

 

[jim dungar]

We are having a new 2000kVA, 25kv/480-277, Y-Y transformer installed on an oil & gas site with both Xo and Ho bushings. Can someone comment on any codes or general practices about whether we should have the utility bring a neutral to the Ho?

What the utility does with their side of a Y-Y transformer usually does not impact what you do with your side.
Their termination to their H0 depends on their system, let them dictate what is conected.

The only problem is if you do not want to have your X0 directly bonded to the utility's H0.
This would only happen if you were implementing a non-solidly grounded secondary (e.g. you were using a high resistance ground).