Definitely check polarity on each string. Could be positives and negatives are mixed up and the wire colors are adding to the confusion.
August *From:* RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org] *On Behalf Of *Roy Rakobitsch *Sent:* Wednesday, September 07, 2016 3:35 PM *To:* RE-wrenches *Subject:* Re: [RE-wrenches] Troubleshooting Stumper - Homerun Interference in Conduit/Inverter Turning Off/On Rapidly Have you measured the current of each string simultaneously while the issue was happening? Have you verified correct polarity on each string? Roy Rakobitsch NABCEP Certified Small Wind Installer® Certified Advanced Tower Climbing, Safety & Rescue Wind/PV Design Engineer Windsine LLC 631-514-4166 www.windsine.org On Sep 7, 2016 4:45 PM, "Matt Partymiller" <m...@solar-energy-solutions.com> wrote: Wrenches, One of our systems is having an issue I have not encountered before where the inverter switches between nighttime mode and interconnection every few seconds. I am hoping for some technical wisdom from the community. We have an array of 20 TrinaSmart modules in two strings of 10. The array is connected to a Solectria 3.8 kW inverter. The conduit run is simple, all four homerun wires (#10 PVwire) in 1" EMT down to the proximity of the Solectria inverter where the conduit switches to 1" LFMC before entering the inverter. The run is about 20', straight down the side of the wall before hitting the inverter. A 600V jacketed communications wire was also in the conduit but has since been removed and run separately. Our inverter is starting up, running for a few seconds, giving a low voltage error, briefly showing nighttime mode, then going into startup mode again. Solectria was gracious enough to send us a new inverter but we have the exact same issue. They tell us their error codes (266, 274) indicate 0 volts. The transition between low voltage error and startup is almost instant. Basically we have 20 seconds of start up, 5 seconds of run, 5 seconds of error then repeat. This is not a grid problem, the identical system next door works fine. In the process of troubleshooting, our technician pulled all four homerun wires out of our conduit and meggered them. They all tested fine so he connected to the inverter. The inverter worked fine. The technician verified grounding of the array and conduit, pulled new homeruns back through the conduit, and reconnected to the inverter. He had the same error as before. He connected each string separately to the inverter by removing the string fuses. Either string will operate fine independently. With string one in conduit and either homerun of string two in conduit (but not both) the inverter operates fine. With string two in conduit but string one outside of conduit, the inverter does not operate. I was certain the error had something to do with homerun roof wiring so I went out with the technician and removed and checked pretty much every module. Everything appears fine, all connections solid, all homeruns have been remade at least once at this point. Now I am stumped and lack the technical knowledge to diagnose the problem. I would be extremely grateful if an esteemed wrench can provide technical support/advice. Thanks, Matt Matthew Partymiller Solar Energy Solutions LLC (877) 312-7456 m...@solar-energy-solutions.com _______________________________________________ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org
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