[RE-wrenches] Single phase to three phase interconnect

[Hans Frederickson]

Eric,

For a 6kW system on a reasonable size commercial service, it shouldn't be a
problem to stack your 2 inverters on one or two legs of the 3-phase service.
Loads are never perfectly balanced, so synchronous generators don't need to
be either, up to a point. Ask the utility if you can feed the 6kW in on one
leg. They'll look at their transformer for the service in question and make
a decision. If they let you do it, just try to feed in on the most heavily
loaded leg of the 3-phase service.

 

Regards,

-Hans

 

From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Eric Thomas
Sent: Monday, April 25, 2011 11:01 AM
To: re-wrenches at lists.re-wrenches.org
Subject: [RE-wrenches] Single phase to three phase interconnect

 

While commercial solar work is newer to me, im surprised this hasn't been
addressed very much in our forum: Interconnecting single phase inverters to
three phase services. We are laying out a 6kW system using Silicon Energy
Cascade modules and Aurora PVI inverters (either 2 or 3 PVI 3.0's). The
challenge is finding a way to easily tie two of these inverters into the
existing 3phase service. I've been reading up on Sunny Boys tech notes and
on this forum about imbalance and such, but im still not comfortable enough
with tie in. Due to the string configuration options, I can add a third
inverter and use a three phase subpanel to aggregate the inverters then tie
them in. But adding a third inverter seems like a goofy solution. In looking
at available equipment, transformers, phase converters etc, I can't seem to
find the right fit. Any ideas?

This system does not have a three phase inverter option due to Made in WA
req's. 

Thanks!

Eric Thomas
Solar Epiphany LLC

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