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.
Dana
--
Dana Brandt
Ecotech Energy Systems, LLC
www.ecotechenergy.com <http://www.ecotechenergy.com>
[EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]>
360.510.0433
On Wed, Nov 26, 2008 at 10:20 AM, <[EMAIL PROTECTED]
<mailto:[EMAIL PROTECTED]>> wrote:
Hi Tump,
Yes, the SI & SB system is all it's cracked up to be!
I'm not sure what is possible in the US but we've been running a 60kW
Sunny Island system for over a year now which powers the Scottish
Isle of Eigg and uses PV's with Sunny Boys, wind turbines with Windy
Boys, 100kW hydro turbine & back-up diesel generation. Power is
distributed around the island at 3.3kV three-phase using step-up &
step-down transformers. The generation is located at various parts of
the island (as are the houses & loads) with the Sunny Islands/Battery
Store & back-up diesels roughly in the middle.
See our website for a full description:
http://www.windandsun.co.uk/projects_eigg.htm
The Sunny Island inverters use 'Frequency Shift Power Control' -
variations in island grid frequency to communicate control signals to
the generation sources and to bonus loads. If the batteries cannot
absorb the renewable power being generated onto the network (if they
are full, or the power generated exceeds the inverter/charger
capacity), the Sunny Island inverters raise the system frequency.
Sunny Boy & Windy Boy inverters are set to 'Off-Grid' mode to respond
to this frequency rise and back off power being fed into the system.
Other renewable generation (eg. hydro turbines) that is able to
respond to this frequency rise to restrict their power output can
also be incorporated in the system.
The raised frequency can also be used to trigger switching on of
bonus loads when there is surplus renewable energy output.
The great thing about using this frequency shift for control is that
no communication cabling, special circuits or dedicated switching is
required and distance is no problem.
The other great thing about using the Sunny Island system is that it
allows use of the Sunny Webbox for remote monitoring. This means
every morning I can check on the internet to see how the system is
performing, view state of charge of batteries, and dial in to change
things if needed. Furthermore, several people can do this at once -
eg. system owners & SMA technical support - so we can all look at
what's been happening and discuss any events. (I'm sure you all know
how useful this can be!)
As an example the attached Word document shows how the frequency
shift works in practice (Hope it's Ok to send attachments on this
list)
Regards
Steve Wade
From: "Tump" <[EMAIL PROTECTED]
<mailto:[EMAIL PROTECTED]>>
To: "'RE-wrenches'"
<[email protected]
<mailto:[email protected]>>
Date sent: Wed, 26 Nov 2008 08:33:38 -0500 Subject:
Re:
[RE-wrenches] More on AC coupling Send reply to: RE-wrenches
<[email protected]
<mailto:[email protected]>>
<mailto:[EMAIL PROTECTED]
<mailto:[EMAIL PROTECTED]>
wrenches.org?subject=unsubscribe
<http://wrenches.org?subject=unsubscribe>
>
<mailto:[EMAIL PROTECTED]
<mailto:[EMAIL PROTECTED]>?subject=subscribe>
> Matt, I have long been interested in installing the SMA SI &
SBs but
> I have a VERY tough time selling $9ks worth of inverters, just to
> get things started. In the system below I would not of hesitated in
> installing the SMA SI & SB! I too agree that w/this type of
scenario
> described below, I would have given quite a bit of thought to
using
> the SMAs. Can't beat the battery charging, no charge controllers &
> expandability.
> Please if there is someone out there that has had experience
w/ the
> SMA SI
> & SB let us know if it is all that it is cracked up to be!
> With passport in hand, I offer my help if someone out there has a
> large system like this, that will be using the SI & SB/WB type of
> set up. TUMP
>
Wind & Sun Ltd., Humber Marsh, Stoke Prior,
Leominster, Herefordshire, HR6 0NR.
Web: www.windandsun.co.uk <http://www.windandsun.co.uk>
Tel: 01568 -760671
Fax: 01568-760484
The latest edition of the Wind & Sun Design Guide & Catalogue is now
available.
This has 112 pages detailing our product range and is packed with
information
and advice about setting up or using a wind or solar electrical
system.
Price is £5.00 + £1.00 p&p.
Wind & Sun Ltd
Registered in England & Wales, Company Number 3403803
VAT Number GB 448 5458 14,
Registered Office: Humber Marsh, Stoke Prior, Leominster,
Herefordshire, HR6 0NR
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