Bob, Ray, Glenn, Thanks for the responses. We could cycle through the inverters and see if it is one, or some combinations of inverters, which is causing the problem. This results in a minimum of 6 trials. If it is a combination of inverters many more.
Any feedback on the idea of monitoring the AC circuits; computer feed and combined inverter output? Seems to me this might provide a one step correlation between the event and the cause. Just not sure what equipment to suggest for this. Could be there is some other cause, unrelated to the inverters. AC unit kicking on, etc. Though they do not see any lights dimiming/brightening, or any other notable change in electrical equipment at the sight. On Mon, Aug 4, 2014 at 1:03 PM, Glenn Burt <glenn.b...@glbcc.com> wrote: > I wonder if the UPS is grumbling about high voltage as the inverters > push back current... > > Glenn > ------------------------------ > From: Carl Adams <swingjun...@gmail.com> > Sent: 8/4/2014 10:29 > To: RE-wrenches <re-wrenches@lists.re-wrenches.org> > Subject: [RE-wrenches] UPS disturbance with SMA Inverters > > Hello Wrenches, > > I have a site which is experiencing nuisance disturbance of the computer > UPS systems at the site. The site owner "suspects" this is due to the PV > system which is a 50 kW system using 6 SMA SunnyBoy inverters. The > nuisance disturbance is a clicking noise in the UPS units. The disturbance > is not enough to cause the UPS to engage, so it seems to be a small > disturbance on the AC power. The site owner "suspects" the inverters are > the source of this disturbance since 1) It seems to only occur when we have > a good solar day. 2) If the inverters are shut down the problem goes away, > and if you start up the inverters the problem exhibits again. > > The site was commissioned in March of 2012 and has had no problems till > this issue last month. In reviewing the event log on Sunny Portal there > are no inverter anomalies. SMA tech support had not run into this issue > and had no ideas, they too agree the inverters are not reporting any > anomalies. > > The problem is not persistent but rather intermittent making this harder > to troubleshoot. > > So my questions are > 1) Has anyone else seen this sort of issue before, related to SMA SunnyBoy > inverters. > 2) Can you recommend an AC power monitoring tool which would support > frequency and voltage monitoring on the AC line. Perhaps one data set on > the circuit feeding the computers and another on the inverter output > circuit. > > For clarity the six SunnyBoys feed into an AC Combiner panel which > backfeeds into the building main distribution panel. The service is 240V > single phase. > > With Regards > Carl Adams, SunRock Solar > NABCEP Certified PV Installer > > _______________________________________________ > 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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