[RE-wrenches] UPS disturbance with SMA Inverters

[Carl Adams]

William,

Thanks for posting this.
Couple of questions:
1) Does the time stamp of the irregular wave form correspond to the UPS
beeping?  Perhaps if you are monitoring it remotely you cannot answer this.

2) Does this output waveform represent the input to the the UPS?
3) What equipment and software are you using for the monitoring?

I checked in with our site owner just before reading your post.  He said
the only thing he had done was shut down 3 of the 6 inverters.  Left them
off for a short period of time (in which no UPS irregularities occurred)
and then turned them back on.  They have then run for the past 4-5 days
with no issue.  Intermittent problems are hard to track down.

Since we have live people sitting in from of the computers (connected to
the complaining UPS) with the right software/hardware for monitoring they
might be able to correlate the occurrence in real time.  Let me know what
you are using.

With respect to  the remote monitoring software, I have used RealVNC(aka
Teamviewer)  in years past (when it was an open source free tool) and found
it to be a very good tool.  I'd be interested in your thoughts of the
current product.


On Sat, Aug 9, 2014 at 1:36 PM, William Miller <william at millersolar.com>
wrote:

> Friends:
>
>
>
> I am experiencing an almost identical problem.  The system I am working on
> has an SMA mini-grid with 3 Sunny Islands and 3 Sunny Boys.  The UPS in the
> AV room has been beeping.  I installed a data acquisition system and have
> been monitoring the waveform.  I will try to insert two screen shots below,
> but I am not sure if they will pass thorough the list-serve.  It looks like
> we may be seeing some distortion, although this may be an artifact of the
> data acquisition system.  I am interested in any comments any of you may
> have that might shed some light on this.
>
>
>
> I did search for the transition point between the two waveforms. The
> waveform went from one shape to the other gradually over about 5 seconds.
> The more irregular shape is rarely exhibited in the week or so that I have
> been monitoring.
>
>
>
> William Miller
>
>
>
> PS:  I have been demoing Team Viewer.  I need to license some form of
> remote access software.  Can anyone make a recommendation?
>
>
>
> Wm
>
>
>
>
>
>
>
>
>
> [image: Gradient Cap_mini]
> Lic 773985
> millersolar.com <http://www.millersolar.com/>
> 805-438-5600
>
>
>
> *From:* RE-wrenches [mailto:re-wrenches-bounces at lists.re-wrenches.org] *On
> Behalf Of *Carl Adams
> *Sent:* Monday, August 04, 2014 7:29 AM
> *To:* RE-wrenches
> *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
>
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