<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns="http://www.w3.org/TR/REC-html40">
<head>
<meta http-equiv=Content-Type content="text/html; charset=us-ascii">
<meta name=Generator content="Microsoft Word 11 (filtered medium)">
<style>
<!--
/* Font Definitions */
@font-face
{font-family:Tahoma;
panose-1:2 11 6 4 3 5 4 4 2 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0cm;
margin-bottom:.0001pt;
font-size:12.0pt;
font-family:"Times New Roman";}
a:link, span.MsoHyperlink
{color:blue;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{color:blue;
text-decoration:underline;}
span.EmailStyle17
{mso-style-type:personal-reply;
font-family:Arial;
color:blue;
font-weight:normal;
font-style:normal;
text-decoration:none none;}
@page Section1
{size:595.3pt 841.9pt;
margin:72.0pt 90.0pt 72.0pt 90.0pt;}
div.Section1
{page:Section1;}
-->
</style>
<!--[if gte mso 9]><xml>
<o:shapedefaults v:ext="edit" spidmax="1026" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext="edit">
<o:idmap v:ext="edit" data="1" />
</o:shapelayout></xml><![endif]-->
</head>
<body lang=EN-GB link=blue vlink=blue>
<div class=Section1>
<p class=MsoNormal><font size=4 color=blue face=Arial><span style='font-size:
14.0pt;font-family:Arial;color:blue'>Chris,<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=4 color=blue face=Arial><span style='font-size:
14.0pt;font-family:Arial;color:blue'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=4 color=blue face=Arial><span style='font-size:
14.0pt;font-family:Arial;color:blue'>I just wanted to say thanks for coming
onto the list and giving more detail of what you have achieved. I have long
believed that with a little more understanding and thought, PV and a diesel (or
gas) derived grid will become common place, and will eliminate the need for a
battery bank on many systems.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=4 color=blue face=Arial><span style='font-size:
14.0pt;font-family:Arial;color:blue'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=4 color=blue face=Arial><span style='font-size:
14.0pt;font-family:Arial;color:blue'>Cheers,<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=4 color=blue face=Arial><span style='font-size:
14.0pt;font-family:Arial;color:blue'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=4 color=blue face=Arial><span style='font-size:
14.0pt;font-family:Arial;color:blue'>Carl Emerson.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=4 color=blue face=Arial><span style='font-size:
14.0pt;font-family:Arial;color:blue'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=4 color=blue face=Arial><span style='font-size:
14.0pt;font-family:Arial;color:blue'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=4 color=blue face=Arial><span style='font-size:
14.0pt;font-family:Arial;color:blue'><o:p> </o:p></span></font></p>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span lang=EN-US
style='font-size:12.0pt'><o:p> </o:p></span></font></p>
<p class=MsoNormal><b><font size=2 face=Tahoma><span lang=EN-US
style='font-size:10.0pt;font-family:Tahoma;font-weight:bold'>Subject:</span></font></b><font
size=2 face=Tahoma><span lang=EN-US style='font-size:10.0pt;font-family:Tahoma'>
Re: [RE-wrenches] Generator Controlled Mini Grid</span></font><span lang=EN-US><o:p></o:p></span></p>
</div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>I am connecting a Kohler 12RES to my house, the roof has 3.1KW of PV
connected to a SB3000.<o:p></o:p></span></font></p>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>I thought we would have problems so we all knew to turn of the solar
before turning on the generator. One day, we forgot, and it all worked. Since
that I have left the solar on each time we ran the generator. As we are in a
small island, power outages are common.<o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>The Kohler has a problem I cannot get to the bottom of and I'm going to
pull a Generac from inventory and install it, so I will find out if that also
works. My home and office is a test lab, I'll try anything there.<o:p></o:p></span></font></p>
</div>
</div>
<div>
<p class=MsoNormal style='margin-bottom:12.0pt'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'><o:p> </o:p></span></font></p>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>On Mon, Feb 11, 2013 at 8:44 AM, Drake <<a
href="mailto:drake.chamberlin@redwoodalliance.org" target="_blank">drake.chamberlin@redwoodalliance.org</a>>
wrote:<o:p></o:p></span></font></p>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>Chris,<br>
<br>
It sounds like you are creating a generator supplied mini grid, if I understand
correctly, My reading is that your generator is creating the AC voltage,
and the inverter is synchronizing with it, allowing power to be fed into the
system from a PV source. <br>
<br>
This approach could represent a major innovation in solar industry. I
remember a decade or so ago when it was proposed, on this list, that battery
based inverters could be backfed to charge batteries, and someone tried
it. It worked. Today AC coupling is standard operating
procedure. <br>
<br>
Up to that time, it was only understood that to connect an AC source to the
output of a battery based inverter could damage it. Maybe the next step
is to AC couple to generator supplied sub panels and allow PV usage during
power outages. <br>
<br>
What inverter and generator are you using? How many Watts of PV are
connected?<br>
<br>
Thank you,<br>
<br>
Drake <o:p></o:p></span></font></p>
<div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><br>
<br>
<br>
At 02:04 PM 2/10/2013, you wrote:<br>
<br>
<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>I have a generator and PV system that just works together, despite all
the dire predictions that it won't. from my experience of PV and generators (I
am also a generator tech), the biggest issue is the AVR board and how it
responds to back fed voltage, and the generator controller's over voltage
settings.<br>
I think that it would probably on only require a reprogrammed inverter to make
this work as follows.<br>
The AVR produces excitation voltage to vary the strength of the rotor field and
therefore the induced voltage in the stator. When the PV system back feeds the
generator, the excitation level is reduced to control the voltage. When there
is no load, the inverter keeps raising the voltage to attempt to push the
current to the grid and at some point the generator trips out on overvoltage. <br>
<br>
If the inverter was programmed to reduce the production of power in
response to the rise in voltage, it would sync pretty nicely with the
generator. However, this would likely violate the IEEE parameters for a grid
tied inverter. SMA has off-grid mode, I suspect that is the best solution.<br>
<br>
In a Sunny Island system, as I understand it, the Sunny Island caries the
frequency to communicate to the inverter to reduce the current output. That
avoid the problem of the inverter raising the voltage.<br>
<br>
<br>
<br>
<br>
On Sun, Feb 10, 2013 at 2:45 PM, Drake <<a
href="mailto:drake.chamberlin@redwoodalliance.org" target="_blank">
drake.chamberlin@redwoodalliance.org</a>> wrote:<o:p></o:p></span></font></p>
<p class=MsoNormal style='mso-margin-top-alt:0cm;margin-right:0cm;margin-bottom:
12.0pt;margin-left:36.0pt'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'>Hi Kevin,<o:p></o:p></span></font></p>
<p class=MsoNormal style='mso-margin-top-alt:0cm;margin-right:0cm;margin-bottom:
12.0pt;margin-left:36.0pt'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'>Thanks for the Eigg video. What a great place.<o:p></o:p></span></font></p>
<p class=MsoNormal style='mso-margin-top-alt:0cm;margin-right:0cm;margin-bottom:
12.0pt;margin-left:36.0pt'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'>I didn't see evidence of any AC coupling of inverter
produced AC to a generator produced mini grid. I understand this is being
done in a homebrew manner by some.<o:p></o:p></span></font></p>
<p class=MsoNormal style='mso-margin-top-alt:0cm;margin-right:0cm;margin-bottom:
12.0pt;margin-left:36.0pt'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'>The current wisdom on the issue is that the less the
PV contribution to the generator supplied grid is, the easier. It would
seem that if a grid tie inverter output could be regulated, using Sunny Island
type controls, it should be possible to have a small inverter generator create
a mini grid that could be fed by PV.<o:p></o:p></span></font></p>
<p class=MsoNormal style='mso-margin-top-alt:0cm;margin-right:0cm;margin-bottom:
12.0pt;margin-left:36.0pt'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'>A system featuring this type of technology was linked
in a posting on this list some years ago, The link seems dead now. In
that case a large generator was feeding a number of houses, and PV was fed into
the system.<o:p></o:p></span></font></p>
<p class=MsoNormal style='mso-margin-top-alt:0cm;margin-right:0cm;margin-bottom:
12.0pt;margin-left:36.0pt'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'>The reason for this interest is that battery backup
systems are much more expensive than generators. We need to find a way to
utilize PV arrays during outages without the expense of battery backup systems.<o:p></o:p></span></font></p>
<p class=MsoNormal style='margin-left:36.0pt'><font size=3 color="#888888"
face="Times New Roman"><span style='font-size:12.0pt;color:#888888'>Drake</span></font><o:p></o:p></p>
<p class=MsoNormal style='margin-bottom:12.0pt'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'><br>
<br>
<br>
<o:p></o:p></span></font></p>
<p class=MsoNormal style='margin-left:36.0pt'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'>At 07:42 PM 2/8/2013, you
wrote:<o:p></o:p></span></font></p>
<p class=MsoNormal style='mso-margin-top-alt:0cm;margin-right:0cm;margin-bottom:
12.0pt;margin-left:36.0pt'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'>Hi Drake,<o:p></o:p></span></font></p>
<p class=MsoNormal style='margin-left:36.0pt'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'>SMA has very good
solutions for this. Does this out of the box without a bunch of custom control
systems. I have put a few systems in like this, but the renewables not yet
online (generator / battery now). If you google Isle of Eig you will find some
info on what they have done there.<o:p></o:p></span></font></p>
<p class=MsoNormal style='mso-margin-top-alt:0cm;margin-right:0cm;margin-bottom:
12.0pt;margin-left:36.0pt'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'><a
href="http://islandsgoinggreen.org/about/eigg-electric/" target="_blank">http://islandsgoinggreen.org/about/eigg-electric/</a><o:p></o:p></span></font></p>
<p class=MsoNormal style='mso-margin-top-alt:0cm;margin-right:0cm;margin-bottom:
12.0pt;margin-left:36.0pt'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'>Kevin<o:p></o:p></span></font></p>
<p class=MsoNormal style='margin-left:36.0pt'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'>-----Original
Message-----<o:p></o:p></span></font></p>
<p class=MsoNormal style='margin-left:36.0pt'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'>From: <a
href="mailto:re-wrenches-bounces@lists.re-wrenches.org" target="_blank">re-wrenches-bounces@lists.re-wrenches.org</a><o:p></o:p></span></font></p>
<p class=MsoNormal style='margin-left:36.0pt'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'>[<a
href="mailto:re-wrenches-bounces@lists.re-wrenches.org" target="_blank">
mailto:re-wrenches-bounces@lists.re-wrenches.org</a>]On Behalf Of Drake<o:p></o:p></span></font></p>
<p class=MsoNormal style='margin-left:36.0pt'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'>Sent: February 8, 2013
6:41 AM<o:p></o:p></span></font></p>
<p class=MsoNormal style='margin-left:36.0pt'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'>To: RE-wrenches<o:p></o:p></span></font></p>
<p class=MsoNormal style='mso-margin-top-alt:0cm;margin-right:0cm;margin-bottom:
12.0pt;margin-left:36.0pt'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'>Subject: [RE-wrenches] Generator Controlled Mini Grid<br>
<br>
<o:p></o:p></span></font></p>
<p class=MsoNormal style='margin-left:36.0pt'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'>A potential customer is
interested in a mini grid, set up by a<o:p></o:p></span></font></p>
<p class=MsoNormal style='mso-margin-top-alt:0cm;margin-right:0cm;margin-bottom:
12.0pt;margin-left:36.0pt'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'>generator, to connect his array to.<o:p></o:p></span></font></p>
<p class=MsoNormal style='margin-left:36.0pt'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'>Some years back, on this
list, an article was linked about a<o:p></o:p></span></font></p>
<p class=MsoNormal style='margin-left:36.0pt'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'>community with a central
generator that had PV input to the generator<o:p></o:p></span></font></p>
<p class=MsoNormal style='mso-margin-top-alt:0cm;margin-right:0cm;margin-bottom:
12.0pt;margin-left:36.0pt'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'>supplied, local grid, using electronic controls.<o:p></o:p></span></font></p>
<p class=MsoNormal style='margin-left:36.0pt'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'>Has any progress been
made in this technology? Does anyone have a<o:p></o:p></span></font></p>
<p class=MsoNormal style='mso-margin-top-alt:0cm;margin-right:0cm;margin-bottom:
12.0pt;margin-left:36.0pt'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'>link to the electronic control equipment or any other
relevant information?<o:p></o:p></span></font></p>
<p class=MsoNormal style='mso-margin-top-alt:0cm;margin-right:0cm;margin-bottom:
12.0pt;margin-left:36.0pt'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'>Thanks,<o:p></o:p></span></font></p>
<p class=MsoNormal style='mso-margin-top-alt:0cm;margin-right:0cm;margin-bottom:
12.0pt;margin-left:36.0pt'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'>Drake<o:p></o:p></span></font></p>
<p class=MsoNormal style='margin-left:36.0pt'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'>_______________________________________________<o:p></o:p></span></font></p>
<p class=MsoNormal style='mso-margin-top-alt:0cm;margin-right:0cm;margin-bottom:
12.0pt;margin-left:36.0pt'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'>List sponsored by Home Power magazine<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
<p class=MsoNormal style='margin-left:36.0pt'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'>_______________________________________________<o:p></o:p></span></font></p>
<p class=MsoNormal style='mso-margin-top-alt:0cm;margin-right:0cm;margin-bottom:
12.0pt;margin-left:36.0pt'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'>List sponsored by Home Power magazine<o:p></o:p></span></font></p>
<p class=MsoNormal style='mso-margin-top-alt:0cm;margin-right:0cm;margin-bottom:
12.0pt;margin-left:36.0pt'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'>List Address: <a
href="mailto:RE-wrenches@lists.re-wrenches.org" target="_blank">RE-wrenches@lists.re-wrenches.org</a><o:p></o:p></span></font></p>
<p class=MsoNormal style='margin-left:36.0pt'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'>Options & settings:<o:p></o:p></span></font></p>
<p class=MsoNormal style='mso-margin-top-alt:0cm;margin-right:0cm;margin-bottom:
12.0pt;margin-left:36.0pt'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'><a
href="http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org"
target="_blank">http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org</a>
<o:p></o:p></span></font></p>
<p class=MsoNormal style='mso-margin-top-alt:0cm;margin-right:0cm;margin-bottom:
12.0pt;margin-left:36.0pt'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'>List-Archive: <a
href="http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org"
target="_blank">http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org</a><o:p></o:p></span></font></p>
<p class=MsoNormal style='margin-left:36.0pt'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'>List rules &
etiquette:<o:p></o:p></span></font></p>
<p class=MsoNormal style='mso-margin-top-alt:0cm;margin-right:0cm;margin-bottom:
12.0pt;margin-left:36.0pt'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'><a href="http://www.re-wrenches.org/etiquette.htm"
target="_blank">www.re-wrenches.org/etiquette.htm</a><o:p></o:p></span></font></p>
<p class=MsoNormal style='margin-left:36.0pt'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'>Check out participant
bios:<o:p></o:p></span></font></p>
<p class=MsoNormal style='mso-margin-top-alt:0cm;margin-right:0cm;margin-bottom:
12.0pt;margin-left:36.0pt'><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'><a href="http://www.members.re-wrenches.org"
target="_blank">www.members.re-wrenches.org</a><o:p></o:p></span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><br>
<br>
<br>
-- <br>
Chris Mason<br>
President, Comet Systems Ltd<br>
<a href="http://www.cometenergysystems.com" target="_blank">www.cometenergysystems.com</a>
<br>
Cell: <a href="tel:264.235.5670" target="_blank" value="+12642355670">264.235.5670</a><br>
Skype: netconcepts<br>
_______________________________________________<br>
List sponsored by Home Power magazine<br>
<br>
List Address: <a href="mailto:RE-wrenches@lists.re-wrenches.org" target="_blank">RE-wrenches@lists.re-wrenches.org</a><br>
<br>
Options & settings:<br>
<a href="http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org"
target="_blank">http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org</a>
<br>
<br>
List-Archive: <a
href="http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org"
target="_blank">http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org</a><br>
<br>
List rules & etiquette:<br>
<a href="http://www.re-wrenches.org/etiquette.htm" target="_blank">www.re-wrenches.org/etiquette.htm</a><br>
<br>
Check out participant bios:<br>
<a href="http://www.members.re-wrenches.org/" target="_blank">www.members.re-wrenches.org</a><o:p></o:p></span></font></p>
</div>
</div>
</div>
<p class=MsoNormal style='margin-bottom:12.0pt'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'><br>
_______________________________________________<br>
List sponsored by Home Power magazine<br>
<br>
List Address: <a href="mailto:RE-wrenches@lists.re-wrenches.org">RE-wrenches@lists.re-wrenches.org</a><br>
<br>
Options & settings:<br>
<a href="http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org"
target="_blank">http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org</a><br>
<br>
List-Archive: <a
href="http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org"
target="_blank">http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org</a><br>
<br>
List rules & etiquette:<br>
<a href="http://www.re-wrenches.org/etiquette.htm" target="_blank">www.re-wrenches.org/etiquette.htm</a><br>
<br>
Check out participant bios:<br>
<a href="http://www.members.re-wrenches.org" target="_blank">www.members.re-wrenches.org</a><br>
<br>
<o:p></o:p></span></font></p>
</div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><br>
<br clear=all>
<o:p></o:p></span></font></p>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
</div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>-- <br>
Chris Mason<o:p></o:p></span></font></p>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>President, Comet Systems Ltd<o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><a href="http://www.cometenergysystems.com" target="_blank">www.cometenergysystems.com</a><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>Cell: 264.235.5670<o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>Skype: netconcepts<o:p></o:p></span></font></p>
</div>
</div>
</div>
</body>
</html>