Enphase Inverters / Step-Up Transformer

[AFerguson]

Utility transformer 13.2kV-480Y/277V (wye-wye). Enphase inverter output 208Y/120V; have in-stock a 45kVA 208Y/120V-480V delta transformer.

For a normal generator, would assume we would not parallel services; however, the inverter sine waves are controlled by the utility, so would they even care about the phase shift?

Would this configuration work or do I need to stick with wye-wye?

 

[davidbeach]

Probably should specifically ask the serving utility. Could be that they would require a wye-wye or even delta on the 208 side and wye on the 480.

 

[AFerguson]

I agree and am waiting on their response. Interesting thing is these units are not really generating their own sine waves and simply track whatever they "see", so the phase shift may not matter from an operational standpoint.

 

[davidbeach]

Phase shift is of no concern. Ground source or not ground source is of far more interest.

 

[AFerguson]

System is supposed to be balanced and the inverters have ground-fault protection. Would think this would be sufficient on this separately derived system in this case. You would have a better feel for utility protocol than I - thoughts?

 

[davidbeach]

I'm talking about how it presents itself to the utility; how you go about complying with IEEE 1547 clause 4.1.2.