Utility Solar Project Grounding Question

C

cyriousn

Senior Member
Location
ME / CT
Occupation
EE & BIM
I'm reviewing a ground mounted utility scale solar project and I'm questioning my understanding how this project should be grounded.

The project connects to a 23kv 4-wire network, goes through a 2MVA Yg-Yg transformer to a 2500A 600V switchboard.

The project shows the ground and neutral bonded at the secondary of the transformer with both ground and neutral going to the switchboard. The switchboard does not have a bonding jumper installed between neutral and ground bus.

The switchboard connects to multiple inverters and feeds some aux load.

Does this sound correct? I can't get out of my head that we derive the neutral at the first means of disconnect which would be at the switchboard but this is a solar PV project and not a typical electrical service.
 
cyriousn said:
Does this sound correct? I can't get out of my head that we derive the neutral at the first means of disconnect which would be at the switchboard but this is a solar PV project and not a typical electrical service.
Click to expand...
The 600V system can have a neutral to ground system bond at either the transformer or the SWBD (250.30(A)(1)). I prefer the transformer myself, get's it out of the way.
 
cyriousn said:
...

Does this sound correct? I can't get out of my head that we derive the neutral at the first means of disconnect which would be at the switchboard but this is a solar PV project and not a typical electrical service.
Click to expand...

It doesn't really matter that it's PV. The rules for bonding and grounding a separately derived system would apply here for a load, too.

I think we're all assuming the service point is on the 23kV network and the transformer is project owned.
 
jaggedben said:
It doesn't really matter that it's PV. The rules for bonding and grounding a separately derived system would apply here for a load, too.

I think we're all assuming the service point is on the 23kV network and the transformer is project owned.
Click to expand...
Yes the transformer is project owned. Point of change of ownership is back at the 23kv before the project GOAB switch.
 
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