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

[Mark Frye]

Thanks Everyone for the feedback.
 
I am going to go ahead and reduce my projected yield by an additional 5% and
increase the install cost to include a 2kva buck/boost xfmr as an option. If
the economics hold up, I have confidence that we can go forward without the
xfrm, but we will have it in the wings to address voltage faults if they
occur.
 
Mark Frye 
Berkeley Solar Electric Systems 
303 Redbud Way 
Nevada City,  CA 95959 
(530) 401-8024 
 <http://www.berkeleysolar.com/> www.berkeleysolar.com  
 

  _____  

From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Mark Frye
Sent: Monday, February 14, 2011 7:42 PM
To: 'RE-wrenches'
Subject: [RE-wrenches] Can I handle the voltage drop?



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 
 <http://www.berkeleysolar.com> www.berkeleysolar.com  

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org/attachments/20110217/d732eb75/attachment-0004.html>