Hi James - Is there a long run between the inverters and the point of interconnection? As others have pointed out, it appears that the symptoms you describe are voltage drop related. If the wire size is too small it will result in voltage at the inverters going up when current starts to flow. The inverters match the voltage at the utility point of connection. If, for example, the voltage at the main service panel is 240 volts and you have a 10% voltage drop due to undersized wires, you'd see 240 x 1.10 = 264 v at the inverters. Sometimes this issue is compounded if the utility voltage is a little on the high side, which can happen at the end of the distribution lines.
There could be other explanations as well. Best, August On Thu, May 20, 2021 at 10:25 AM Jerry Shafer <jerrysgarag...@gmail.com> wrote: > Wrenches > Looks like the i verter is doing what it should 269 is out of range, what > is the at meter voltage, libe loss or very high output voltage, 41 volts > increase looks like resistance issues. More info would help, distance, wire > size etc. > Jerry > Jerry > > > On Thu, May 20, 2021, 9:52 AM James Reismiller <ja...@abundantsolar.com> > wrote: > >> Hi Folks, >> >> I’m wondering if anybody has ideas on what could be causing grid >> over/undervoltage errors on an install we did about a year ago that now has >> these issues. The site is a 24 kW DC ground mount array with (3) SMA >> SB7.0-1SP-US-40 inverters. I’ve checked and done the following: >> >> 1. Measured voltage min/max at inverter terminals and AC combiner. >> Min – 228VAC (with no inverter output) Max - 269 VAC (when inverter trying >> to connect)! >> 2. Had utility check service and transformer with load meter (with no >> PV running). No issues found and utility engineer stated he thinks it’s on >> our side. >> 3. Checked all AC connections including neutral (seemed like neutral >> issue) from inverters back to supply-side tap (fused disco). >> 4. Changed SMA upper voltage window in grid guard settings to 272V >> max and 264V reconnection. This helped for a while but now is faulting >> again. >> >> >> >> Have any of you ran into this issue and how did you solve it? Or what’s >> the next thing to check? >> >> >> >> Thanks in advance! >> >> >> >> Be Well, >> >> James Reismiller >> >> He/Him/His >> >> NABCEP Certified Solar PV Installer® >> >> Abundant Solar >> >> 541-231-8072 xt. 3 >> >> CCB#175919 >> >> www.abundantsolar.com >> <http://www.abundantsolar.com/abundantsolar/Home.html> >> >> >> >> "Don't get me wrong: I love nuclear energy! It's just that I prefer >> fusion to fission. And it just so happens that there's an enormous fusion >> reactor safely banked a few million miles from us. It delivers more than we >> could ever use in just about 8 minutes. And it's wireless!" >> >> >> >> ~William McDonough >> >> >> _______________________________________________ >> List sponsored by Redwood Alliance >> >> Pay optional member dues here: http://re-wrenches.org >> >> 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 >> >> There are two list archives for searching. When one doesn't work, try the >> other: >> https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/ >> http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org >> >> List rules & etiquette: >> http://www.re-wrenches.org/etiquette.htm >> >> Check out or update participant bios: >> http://www.members.re-wrenches.org >> >> _______________________________________________ > List sponsored by Redwood Alliance > > Pay optional member dues here: http://re-wrenches.org > > 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 > > There are two list archives for searching. When one doesn't work, try the > other: > https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/ > http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org > > List rules & etiquette: > http://www.re-wrenches.org/etiquette.htm > > Check out or update participant bios: > http://www.members.re-wrenches.org > >
_______________________________________________ List sponsored by Redwood Alliance Pay optional member dues here: http://re-wrenches.org 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 There are two list archives for searching. When one doesn't work, try the other: https://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/ http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: http://www.re-wrenches.org/etiquette.htm Check out or update participant bios: http://www.members.re-wrenches.org
