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-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@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 _______________________________________________ _______________________________________________ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
