[RE-wrenches] Can I handle the voltage drop?

[Mark Frye]

Folks,

I am working on a proposal. It's a ground mount 300+ feet from the meter.
There is an existing, near by run of #2 copper I can tap into. The desired
system is relatively large, 64 amps AC max. I have modeled the yield using
PV watts hourly data, applying a power loss based on the voltage drop at the
varying current. This model shows a 3% loss in annual yield with the #2
copper. Because of the economics of the system, we can absorb this loss.

My concern however is that I do not want the inverters to shut down when
operating at higher currents. I do not want a high AC line voltage fault due
to the voltage drop on the line. At the 64 amps max, the drop  would be
about 4%. Of course all the manufactures I talk with recommend keeping the
drop on the AC below 1.5%.

I am looking at using Enphase inverters which spec an AC voltage range up to
264V, or 10% above 240V nominal.

What experience have folks had out there? How far can one realistically push
the 1.5% limit and still avoid AC voltage faults when there is high voltage
drop on the line?

My guess is that everything would work out fine, but I stand to loss a huge
amount of energy if the inverters are spending all their time faulting and
resetting during daily peaks.
 
Mark Frye
Berkeley Solar Electric Systems
303 Redbud Way
Nevada City,  CA 95959
(530) 401-8024
www.berkeleysolar.com 

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