ggunn
PE (Electrical), NABCEP certified
- Location
- Austin, TX, USA
- Occupation
- Consulting Electrical Engineer - Photovoltaic Systems
When designing a supply side interconnected PV system you can build it up to the size in backfed amps as the service, right? Not necessarily; you'd best look at the size of the transformer feeding that service. What I learned last week is that the POCO may provide a transformer that is significantly less in kVA rating than (in this case) the sum of the ratings of the two services it feeds. In the jurisdiction in this case a PV system or systems is/are only allowed to backfeed in system kW rating up to 90% of the kVA rating of the transformer. With PV systems connected to both services that fit under the rules for supply side connected PV, an integrator can exceed that 90% limit and trigger a transformer upgrade, which can be expensive.
This may be old news to some, but I thought I'd share it in hopes that others who encounter this will catch it before their systems are built.
This may be old news to some, but I thought I'd share it in hopes that others who encounter this will catch it before their systems are built.
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