Thanks for the report, Steve. I'm also a huge fan of the European SI. We need to be careful when we start to compare operations across the ocean. The US version of the SI is a bit different from the European version. SMA in Germany decided that the full-featured SI would be too expensive for the US market, so they sent us a stripped down, cheaper version. The US version still has some nice features, but it has some limitations when compared to the full-featured European version. One of the brilliant aspects of the full-featured SI is the multi-master operation. I wrote a little bit on the SI for AC minigrids and the multi-master operation in HP 109 - Oct/Nov 2005. It's frustrating to me that SMA hasn't UL listed a full-featured SI for us in the States, but they must figure it doesn't make financial sense for them.<br>
<br>Dana<br><br>-- <br>Dana Brandt<br>Ecotech Energy Systems, LLC<br><a href="http://www.ecotechenergy.com">www.ecotechenergy.com</a><br><a href="mailto:dana@ecotechenergy.com">dana@ecotechenergy.com</a><br>360.510.0433<br>
<br><br><div class="gmail_quote">On Wed, Nov 26, 2008 at 10:20 AM, <span dir="ltr"><<a href="mailto:Steve@windandsun.co.uk">Steve@windandsun.co.uk</a>></span> wrote:<br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
Hi Tump,<br>
<br>
Yes, the SI & SB system is all it's cracked up to be!<br>
<br>
I'm not sure what is possible in the US but we've been running a 60kW<br>
Sunny Island system for over a year now which powers the Scottish<br>
Isle of Eigg and uses PV's with Sunny Boys, wind turbines with Windy<br>
Boys, 100kW hydro turbine & back-up diesel generation. Power is<br>
distributed around the island at 3.3kV three-phase using step-up &<br>
step-down transformers. The generation is located at various parts of<br>
the island (as are the houses & loads) with the Sunny Islands/Battery<br>
Store & back-up diesels roughly in the middle.<br>
<br>
See our website for a full description:<br>
<a href="http://www.windandsun.co.uk/projects_eigg.htm" target="_blank">http://www.windandsun.co.uk/projects_eigg.htm</a><br>
<br>
The Sunny Island inverters use 'Frequency Shift Power Control' -<br>
variations in island grid frequency to communicate control signals to<br>
the generation sources and to bonus loads. If the batteries cannot<br>
absorb the renewable power being generated onto the network (if they<br>
are full, or the power generated exceeds the inverter/charger<br>
capacity), the Sunny Island inverters raise the system frequency.<br>
Sunny Boy & Windy Boy inverters are set to 'Off-Grid' mode to respond<br>
to this frequency rise and back off power being fed into the system.<br>
Other renewable generation (eg. hydro turbines) that is able to<br>
respond to this frequency rise to restrict their power output can<br>
also be incorporated in the system.<br>
<br>
The raised frequency can also be used to trigger switching on of<br>
bonus loads when there is surplus renewable energy output.<br>
<br>
The great thing about using this frequency shift for control is that<br>
no communication cabling, special circuits or dedicated switching is<br>
required and distance is no problem.<br>
<br>
The other great thing about using the Sunny Island system is that it<br>
allows use of the Sunny Webbox for remote monitoring. This means<br>
every morning I can check on the internet to see how the system is<br>
performing, view state of charge of batteries, and dial in to change<br>
things if needed. Furthermore, several people can do this at once -<br>
eg. system owners & SMA technical support - so we can all look at<br>
what's been happening and discuss any events. (I'm sure you all know<br>
how useful this can be!)<br>
<br>
As an example the attached Word document shows how the frequency<br>
shift works in practice (Hope it's Ok to send attachments on this<br>
list)<br>
<br>
Regards<br>
Steve Wade<br>
<br>
<br>
<br>
From: "Tump" <<a href="mailto:tump@hughes.net">tump@hughes.net</a>><br>
To: "'RE-wrenches'" <<a href="mailto:re-wrenches@lists.re-wrenches.org">re-wrenches@lists.re-wrenches.org</a>><br>
Date sent: Wed, 26 Nov 2008 08:33:38 -0500 Subject: Re:<br>
[RE-wrenches] More on AC coupling Send reply to: RE-wrenches<br>
<<a href="mailto:re-wrenches@lists.re-wrenches.org">re-wrenches@lists.re-wrenches.org</a>><br>
<mailto:<a href="mailto:re-wrenches-request@lists.re-">re-wrenches-request@lists.re-</a><br>
<a href="http://wrenches.org?subject=unsubscribe" target="_blank">wrenches.org?subject=unsubscribe</a><br>
><br>
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<div class="Ih2E3d"><br>
> Matt, I have long been interested in installing the SMA SI & SBs but<br>
> I have a VERY tough time selling $9ks worth of inverters, just to<br>
> get things started. In the system below I would not of hesitated in<br>
> installing the SMA SI & SB! I too agree that w/this type of scenario<br>
> described below, I would have given quite a bit of thought to using<br>
> the SMAs. Can't beat the battery charging, no charge controllers &<br>
> expandability.<br>
> Please if there is someone out there that has had experience w/ the<br>
> SMA SI<br>
> & SB let us know if it is all that it is cracked up to be!<br>
> With passport in hand, I offer my help if someone out there has a<br>
> large system like this, that will be using the SI & SB/WB type of<br>
> set up. TUMP<br>
><br>
<br>
</div>Wind & Sun Ltd., Humber Marsh, Stoke Prior,<br>
Leominster, Herefordshire, HR6 0NR.<br>
Web: <a href="http://www.windandsun.co.uk" target="_blank">www.windandsun.co.uk</a><br>
<br>
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Fax: 01568-760484<br>
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The latest edition of the Wind & Sun Design Guide & Catalogue is now<br>
available.<br>
This has 112 pages detailing our product range and is packed with<br>
information<br>
and advice about setting up or using a wind or solar electrical<br>
system.<br>
Price is 5.00 + 1.00 p&p.<br>
<br>
Wind & Sun Ltd<br>
Registered in England & Wales, Company Number 3403803<br>
VAT Number GB 448 5458 14,<br>
Registered Office: Humber Marsh, Stoke Prior, Leominster,<br>
Herefordshire, HR6 0NR<br>
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