[RE-wrenches] anti islanding?

[Dana Brandt]

Hi August,

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:
http://homepower.com/article/?file=HP130_pg28_ATE_2 or in print in the
Apr/May 2009 (#130) issue.

Dana

Dana Brandt
Ecotech Energy Systems, LLC
www.ecotechenergy.com
dana at ecotechenergy.com
360.510.0433


On Sun, Feb 14, 2010 at 11:25 AM, August Goers <august at luminalt.com> wrote:

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