Is it possible that the UPS issue is raised voltage, causing the UPS voltage regulator to switch settings? A large amount of solar on a circuit can raise the voltage in the system at full sun. I would rent a Fluke Energy Analyzer and leave it in place for a number of days to see how the voltage, current and power factor varies with the inverter output.
On Mon, Aug 4, 2014 at 5:11 PM, Carl Adams <swingjun...@gmail.com> wrote: > 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 >> >> >> > > _______________________________________________ > 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 > > > -- Chris Mason NABCEP Certified Solar PV Installer™ Solar Design Engineer Generac Generators Industrial technician www.cometsolar.com <http://www.cometenergysystems.com> 264.235.5670 869.662.5670 Skype: netconcepts
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