Solar transformer

E

electro7

Senior Member
Location
Northern CA, US
Occupation
Electrician, Solar and Electrical Contractor
I was wondering if anybody saw an issue connecting a 208V Delta transformer with no neutral to a 208V wye grid? My thoughts and memory is that it isn't a problem, but I wanted to confirm.

Scenario is: grid 3 phase, 208V wye. Solar PV 480V wye. Solar transformer then would be 3 phase 208V Delta (no neutral) on primary side and 480V wye (w/ neutral) on secondary side for 480V Solar PV inverter.

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G

ggunn

PE (Electrical), NABCEP certified
Location
Austin, TX, USA
Occupation
Consulting Electrical Engineer - Photovoltaic Systems
electro7 said:
I was wondering if anybody saw an issue connecting a 208V Delta transformer with no neutral to a 208V wye grid? My thoughts and memory is that it isn't a problem, but I wanted to confirm.

Scenario is: grid 3 phase, 208V wye. Solar PV 480V wye. Solar transformer then would be 3 phase 208V Delta (no neutral) on primary side and 480V wye (w/ neutral) on secondary side for 480V Solar PV inverter.

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Not a problem; I have done that many times.
 
electrofelon

electrofelon

Senior Member
Location
Cherry Valley NY, Seattle, WA
electro7 said:
I was wondering if anybody saw an issue connecting a 208V Delta transformer with no neutral to a 208V wye grid? My thoughts and memory is that it isn't a problem, but I wanted to confirm.

Scenario is: grid 3 phase, 208V wye. Solar PV 480V wye. Solar transformer then would be 3 phase 208V Delta (no neutral) on primary side and 480V wye (w/ neutral) on secondary side for 480V Solar PV inverter.

Sent from my SM-S918U using Tapatalk
Click to expand...

I agree with the gunny, no issue in practice, however, note that some utilities have specific requirements, often called "effective grounding" that may require a wye-wye transformer. 'round here it only applies to larger systems, 500 KW or larger that are interconnected to a MGN feeder.
 
G

ggunn

PE (Electrical), NABCEP certified
Location
Austin, TX, USA
Occupation
Consulting Electrical Engineer - Photovoltaic Systems
electrofelon said:
I agree with the gunny, no issue in practice, however, note that some utilities have specific requirements, often called "effective grounding" that may require a wye-wye transformer. 'round here it only applies to larger systems, 500 KW or larger that are interconnected to a MGN feeder.
Click to expand...
Yeah, I have run into that a couple of times. I design such PV systems with a delta connection to the service but in those cases the designs were rejected at plan review.
 
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