Hi gang. If you have any comments or concerns about this email, please contact me off list.
I asked Peter to request his responses off-list, since this is more of an education project aimed at the masses than a wrenching project. Keeping the list pertinent to pro installers is my number 1 priority. That said, I can see where an on-list semi-technical discussion of islanding would be helpful to pros. But not a discussion similar to what Peter has proposed. R Ray Walters wrote at 10:44 AM 7/19/2011: >If you wouldn't mind Peter, I'd like to see this discussion stay on the list. >I'd be interested to learn more about the actual anti-islanding features of >inverters. >What you've described seems to just cover the voltage and frequency windows >that the inverter will grid tie to. >I was always under the impression (perhaps false) that there were additional >software controls to prevent anti-islanding to another inverter. >Bill Brooks seems to know more about UL1741 test procedures. > >R. Walters >[email protected] >Solar Engineer > > > > >On Jul 19, 2011, at 10:04 AM, Peter Parrish wrote: > >> I need to give a group of California educators the simplified explanation of >> inverter anti-islanding. I know the full details are quite complicated and >> have evolved a bit over the past few years, but would the following be an >> acceptable short explanation? >> >> *** Please contact me off-list with comments & edits. Thanks. *** >> >> This is an excerpt from a longer discussion about designing and installing >> grid-tied >> "Inverter anti-islanding is a requirement of the NEC and the Underwriters >> Laboratory test procedures. A somewhat over-simplified version of >> anti-islanding says that if the grid voltage goes out of the range of 216 >> to 264 Vac or if the grid frequency goes out of the range 59.9 to 60.1 Hz, >> the inverter must shut down within one cycle (1/60th of a second). Once in >> this shutdown mode, the grid must come back into compliance (both frequency >> and voltage) for 5 continuous minutes before the inverter may turn on again. >> This is pretty ho-hum. However, two of our laboratory sessions involve >> building a real, grid-connected PV system. So when our students go to turn >> on their system for the first time, they get to experience the >> anti-islanding function first hand." >> >> Peter T. Parrish, Ph.D., President >> California Solar Engineering, Inc. >> 820 Cynthia Ave., Los Angeles, CA 90065 >> CA Lic. 854779, NABCEP Cert. 031806-26 >> [email protected] >> Ph 323-258-8883, Mobile 323-839-6108, Fax 323-258-8885 >> >> >> >> >> >> >> _______________________________________________ >> List sponsored by Home Power magazine >> >> List Address: [email protected] >> >> 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 >> >> > >_______________________________________________ >List sponsored by Home Power magazine > >List Address: [email protected] > >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
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