<p dir="ltr">Have you measured the current of each string simultaneously while the issue was happening? Have you verified correct polarity on each string?<br></p>
<p dir="ltr">Roy Rakobitsch<br>
NABCEP Certified Small Wind Installer®<br>
Certified Advanced Tower Climbing, Safety & Rescue<br>
Wind/PV Design Engineer<br>
Windsine LLC<br>
631-514-4166<br>
<a href="http://www.windsine.org">www.windsine.org</a></p>
<div class="gmail_extra"><br><div class="gmail_quote">On Sep 7, 2016 4:45 PM, "Matt Partymiller" <<a href="mailto:matt@solar-energy-solutions.com">matt@solar-energy-solutions.com</a>> wrote:<br type="attribution"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Wrenches,<br>
<br>
One of our systems is having an issue I have not encountered before where<br>
the inverter switches between nighttime mode and interconnection every few<br>
seconds. I am hoping for some technical wisdom from the community.<br>
<br>
We have an array of 20 TrinaSmart modules in two strings of 10. The array<br>
is connected to a Solectria 3.8 kW inverter. The conduit run is simple,<br>
all four homerun wires (#10 PVwire) in 1" EMT down to the proximity of the<br>
Solectria inverter where the conduit switches to 1" LFMC before entering<br>
the inverter. The run is about 20', straight down the side of the wall<br>
before hitting the inverter. A 600V jacketed communications wire was also<br>
in the conduit but has since been removed and run separately.<br>
<br>
Our inverter is starting up, running for a few seconds, giving a low<br>
voltage error, briefly showing nighttime mode, then going into startup<br>
mode again. Solectria was gracious enough to send us a new inverter but<br>
we have the exact same issue. They tell us their error codes (266, 274)<br>
indicate 0 volts. The transition between low voltage error and startup is<br>
almost instant. Basically we have 20 seconds of start up, 5 seconds of<br>
run, 5 seconds of error then repeat. This is not a grid problem, the<br>
identical system next door works fine.<br>
<br>
In the process of troubleshooting, our technician pulled all four homerun<br>
wires out of our conduit and meggered them. They all tested fine so he<br>
connected to the inverter. The inverter worked fine. The technician<br>
verified grounding of the array and conduit, pulled new homeruns back<br>
through the conduit, and reconnected to the inverter. He had the same<br>
error as before.<br>
<br>
He connected each string separately to the inverter by removing the string<br>
fuses. Either string will operate fine independently. With string one in<br>
conduit and either homerun of string two in conduit (but not both) the<br>
inverter operates fine. With string two in conduit but string one outside<br>
of conduit, the inverter does not operate.<br>
<br>
I was certain the error had something to do with homerun roof wiring so I<br>
went out with the technician and removed and checked pretty much every<br>
module. Everything appears fine, all connections solid, all homeruns have<br>
been remade at least once at this point. Now I am stumped and lack the<br>
technical knowledge to diagnose the problem. I would be extremely<br>
grateful if an esteemed wrench can provide technical support/advice.<br>
<br>
Thanks,<br>
<br>
Matt<br>
<br>
<br>
<br>
<br>
Matthew Partymiller<br>
Solar Energy Solutions LLC<br>
(877) 312-7456<br>
<a href="mailto:matt@solar-energy-solutions.com">matt@solar-energy-solutions.<wbr>com</a><br>
<br>
<br>
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