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<font color="#0000FF">I was recently told by SMA that in the event that
the inverters did connect to generator output, and the load was less than
the inverter output, that the voltage would rise and the inverters would
fall off line. A year or so before I'd been told by another SMA
representative that generator circuit boards had been fried by inverter
backfeed. <br><br>
It would be very good to get to the bottom of this one. <br><br>
</font>At 10:10 PM 3/1/2010, you wrote:<br>
<blockquote type=cite class=cite cite="">Hi folks:<br>
(Eric, by 'directly to the utility grid' I do mean
with a breaker)<br>
Jason and Allen, I agree with what you are saying, in
theory, but in practice, it is not always possible. I am installing
a generator in a couple of weeks for a customer with an existing 9 KW
array. The property's main service is located at a separate
building from the house, loads, and solar. The main panel feeds 200
Amps to the main residence and 200 Amps to a barn building (300 ft
away) The barn building has the array at it, and also the well
pump, which needs to be backed up by the generator. This requires
us to either dig a 300' trench or just leave the system in auto. We
will be utilizing a 200A Automatic Transfer Switch, but we will not be
able to place the generator into Auto mode. The customer
understands the situation, and said that he would leave the genny in
'manual' start mode. I feed good about the situation, will disable
the auto-start system, and will provide competent labelling.<br>
<br>
Nick Soleil<br>
Project Manager<br>
Advanced Alternative Energy Solutions, LLC<br>
PO Box 657<br>
Petaluma, CA 94953<br>
Cell: 707-321-2937<br>
Office: 707-789-9537<br>
Fax: 707-769-9037<br><br>
<br>
<br>
<font face="Tahoma" size=2><b>From:</b> Jason Szumlanski
<Jason@fafcosolar.com><br>
<b>To:</b> re-wrenches@lists.re-wrenches.org<br>
<b>Sent:</b> Mon, March 1, 2010 3:50:23 PM<br>
<b>Subject:</b> Re: [RE-wrenches] Generators and Grid-tie Systems<br>
</font><br>
This is déjà vu.<br><br>
I would say that the only safe and "correct" way is to connect
the PV inverter output on the line side of the transfer switch. If you
are on the generator side of the xfer switch, you are asking for trouble.
The only other choice would be to use a contactor to ensure PV
disconnection when the grid is down - then you could tap the PV on the
load side of the transfer switch. <br><br>
And to answer Eric's #1 question in the original post, you may not need
to resize/replace the panel if you follow this approach. We go with a
line side tap in this scenario unless there is a compelling reason to do
otherwise.<br><br>
Jason Szumlanski<br>
Fafco Solar<br>
<a href="http://fafcosolar.com">http://fafcosolar.com</a><br>
</blockquote><br>
<x-sigsep><p></x-sigsep>
<font color="#0000FF">Drake Chamberlin<br>
Athens Electric<br>
OH License 44810<br>
CO License 3773<br>
NABCEP </font><font size=1 color="#0000FF">TM
</font><font color="#0000FF">Certified PV Installer <br>
Office - 740-448-7328<br>
Mobile - 740-856-9648 </font></body>
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