[RE-wrenches] UPS disturbance with SMA Inverters

William Miller william at millersolar.com
Sat Aug 9 10:36:18 PDT 2014


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

 

 



 



 

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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