Hi August,<br><br>I wrote a not-too-technical description of anti-islanding for the Ask the Experts section of Home Power a while back. You can find it online at: <a href="http://homepower.com/article/?file=HP130_pg28_ATE_2">http://homepower.com/article/?file=HP130_pg28_ATE_2</a> or in print in the Apr/May 2009 (#130) issue.<br>
<br>Dana<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 Sun, Feb 14, 2010 at 11:25 AM, August Goers <span dir="ltr"><<a href="mailto:august@luminalt.com">august@luminalt.com</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;">
Bil, boB, Darryl,<br>
<br>
Thanks for all the input... now I have some good Valentine's Day reading ;-0<br>
<br>
-August<br>
<div class="im"><br>
August Goers<br>
<br>
Luminalt Energy Corporation<br>
O: 415.564.7652<br>
M: 415.559.1525<br>
F: 650.244.9167<br>
<a href="http://www.luminalt.com" target="_blank">www.luminalt.com</a><br>
________________________________________<br>
</div>From: <a href="mailto:re-wrenches-bounces@lists.re-wrenches.org">re-wrenches-bounces@lists.re-wrenches.org</a> [<a href="mailto:re-wrenches-bounces@lists.re-wrenches.org">re-wrenches-bounces@lists.re-wrenches.org</a>] On Behalf Of Bill Brooks [<a href="mailto:billbrooks7@yahoo.com">billbrooks7@yahoo.com</a>]<br>
Sent: Saturday, February 13, 2010 8:45 PM<br>
To: 'RE-wrenches'<br>
Subject: Re: [RE-wrenches] anti islanding?<br>
<div><div></div><div class="h5"><br>
August,<br>
<br>
Probably the best simple explanation is in "Connecting to the Grid",<br>
published by the Interstate Renewable Energy Council and the North Carolina<br>
Solar Center. It is in its 6th edition. I wrote the original version of the<br>
document over 15 years ago.<br>
<br>
Bill.<br>
<br>
Quote from Document:<br>
<br>
"Grid-tied inverters monitor the utility line voltage and frequency<br>
continuously. When abnormal voltage or frequency conditions occur on the<br>
utility system, they shut themselves off quickly (or "cease to energize,"<br>
the phrase that appears in technical interconnection standards).<br>
Unintentional islands with inverters are very difficult to sustain because<br>
the inverter is not designed to regulate output voltage. Instead, these<br>
inverters produce current proportional to the available power from the prime<br>
power source. An Islanding condition would require the source power to match<br>
real and reactive load conditions thus sustain an unintentional island. With<br>
dynamic loads and fixed power source the natural tendency of the island to<br>
shift outside the allowable voltage and frequency limits that would<br>
otherwise cause the inverter to trip. Extensive testing of inverters at<br>
Sandia National Laboratories, under a variety of laboratory-controlled<br>
worst-case conditions, led to the development of specific<br>
islanding-detection (or anti-islanding) techniques and a generalized test<br>
procedure for evaluating the efficacy of any anti-islanding device. These<br>
and other anti-islanding techniques reduce the already low probability of<br>
inverter islanding such that devices that pass this test, which is detailed<br>
in IEEE 1547.1-2005, are considered non-islanding. Informative discussions<br>
of islanding and anti-islanding inverters are included in the annexes to<br>
IEEE 929-2000 and in a study titled Results of Sandia National Laboratories<br>
Grid-Tied Inverter Testing, published in 1998 by Sandia National<br>
Laboratories."<br>
******<br>
<br>
-----Original Message-----<br>
From: <a href="mailto:re-wrenches-bounces@lists.re-wrenches.org">re-wrenches-bounces@lists.re-wrenches.org</a><br>
[mailto:<a href="mailto:re-wrenches-bounces@lists.re-wrenches.org">re-wrenches-bounces@lists.re-wrenches.org</a>] On Behalf Of August Goers<br>
Sent: Saturday, February 13, 2010 8:29 AM<br>
To: RE-wrenches<br>
Subject: [RE-wrenches] anti islanding?<br>
<br>
Hi Wrenches,<br>
<br>
Does anyone know where I can go to read about general information on how<br>
grid tied inver anti islanding works? I'd like to be able to describe this<br>
in better detail to our tech-savvy clients.<br>
<br>
Thanks,<br>
<br>
August<br>
<br>
<br>
August Goers<br>
<br>
Luminalt Energy Corporation<br>
O: 415.564.7652<br>
M: 415.559.1525<br>
F: 650.244.9167<br>
<a href="http://www.luminalt.com" target="_blank">www.luminalt.com</a><br>
_______________________________________________<br>
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