<html><body><span style="font-family:Verdana; color:#000000; font-size:10pt;"><div>Yes this is an interesting case, as are the debug suggestions given. The wire pairs working out of metal conduit point strongly at either ground faulting or inductive coupling. You seem to have eliminated the obvious wiring issues like polarity and grounding. Since you have a working system next door and you are already putting in the
hard work of swapping inverters and wires, it is worth trying to
swap the inverter from that working system with the non-working one.
This would either indict or eliminate the inverter as the culprit. </div><div><br></div><div>It is worth noting that the TrinaSmart modules with Tigo Maximizers are quite capable of being the source of the problem. They attempt to do MPPT at the module level, and can conflict with the inverter's attempts at MPPT. We have had problems with other inverter brands to the extent that power production was impaired, although not as bad as your complete shutdown. It was necessary to use the inverter setup options to shut off MPPT. If Solectria allows this it is worth trying. </div><div>Also I have had problems with Tigo Maximizers on mismatched strings shutting down one string completely to "maximize" others. You may be seeing the effect of communication problems from the maximizer wireless controller. Try disabling them if possible by shutting down their controller with its secret software.</div><div>I'm guessing that plain dumb modules with a plain dumb inverter would not be suffering this shutdown problem. Something in your system is too smart for your own good.</div><div><br></div><div>Don Barch</div><div>Energy Solar<br></div><div><br></div>
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-------- Original Message --------<br><br>
<br>
-----Original Message-----<br>
From: RE-wrenches [<a href="mailto:re-wrenches-bounces@lists.re-wrenches.org">mailto:re-wrenches-bounces@lists.re-wrenches.org</a>] On<br>
Behalf Of Matt Partymiller<br>
Sent: Wednesday, September 07, 2016 4:46 PM<br>
To: <a href="mailto:re-wrenches@lists.re-wrenches.org">re-wrenches@lists.re-wrenches.org</a><br>
Subject: [RE-wrenches] Troubleshooting Stumper - Homerun Interference in<br>
Conduit/Inverter Turning Off/On Rapidly<br>
<br>
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, all<br>
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 the<br>
inverter. The run is about 20', straight down the side of the wall before<br>
hitting the inverter. A 600V jacketed communications wire was also in the<br>
conduit but has since been removed and run separately.<br>
<br>
Our inverter is starting up, running for a few seconds, giving a low voltage<br>
error, briefly showing nighttime mode, then going into startup mode again.<br>
Solectria was gracious enough to send us a new inverter but we have the<br>
exact same issue. They tell us their error codes (266, 274) indicate 0<br>
volts. The transition between low voltage error and startup is almost<br>
instant. Basically we have 20 seconds of start up, 5 seconds of run, 5<br>
seconds of error then repeat. This is not a grid problem, the identical<br>
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 error<br>
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 grateful<br>
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.com</a><br>
<br>
<br>
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