[RE-wrenches] Utility inverter rating

Solarguy ntrei at 1scom.net
Thu Oct 18 13:40:19 PDT 2012


Per the SI install manual: 

Risk of death from back‑feed into the power distribution grid in the event of grid failure.

Once you set the Sunny Boy to stand‑alone grid parameters, the device no longer complies

with IEEE 929 and the IEEE 1547.

The out-of-the-box default for the SI is set to not backfeed if the grid goes away. The backup function causes the SI to fool the GT inverters into thinking the grid’s still around so they keep charging the battery bank even when it’s not. And the SI cannot backfeed normally.

If this legal SMA workaround allows backfeeding during blackouts, a function that violates UL1741 for you or me to perform, the sentence at the top applies. 

My guess is that the patch allows the SI to run during a blackout and since the SI is not designed to be 1709 compliant allowing it to operate with no grid signal may pose a threat to the utility. At least that’s what I’m reading. 

 

Jim Duncan

North Texas Renewable Energy Inc

www.ntrei.com <http://www.ntrei.com/>  

NABCEP PV 031310-57

TECL-27398

ntrei at 1scom.net 

817.917.0527

 

 

 

On 10/18/2012 11:14 AM, Jay Peltz wrote:

Hi Allan

 

I guess I don't understand the utility concern?

Are concerned for their transformers, or

does it have to do with rebates?

 

Thx

 

Jay

 

Peltz power

 

 

 

 

 

 

 


On Oct 18, 2012, at 8:29 AM, Allan Sindelar <allan at positiveenergysolar.com> wrote:

Erika,
This just came up for us recently. I learned this, surprisingly, from a Customer Generation tech at our local utility. We are installing a GTWB system with two SI5048s and two SB5000s. The CG tech spoke with SMA tech support about the possibility of the SIs selling back to the utility as well as the SBs. He learned that there is a software patch that can be installed in the SIs that will allow them to do this, but that SMA will only allow the patch to be installed upon receiving written permission from the utility. This was sufficient for our utility to consider our system to be a 10kW interconnected system.

This is all I know that may help you; I heard nothing about "3 seconds". You might want to explore this further with SMA tech support.
Allan

Allan Sindelar
 <mailto:Allan at positiveenergysolar.com> Allan at positiveenergysolar.com
NABCEP Certified Photovoltaic Installer
NABCEP Certified Technical Sales Professional
New Mexico EE98J Journeyman Electrician
Founder and Chief Technology Officer
Positive Energy, Inc.
3209 Richards Lane (note new address)
Santa Fe, New Mexico 87507
505 424-1112
www.positiveenergysolar.com <http://www.positiveenergysolar.com/>  

 

 

 

 

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