[RE-wrenches] Anti-Islanding Explanantion

[R Ray Walters]

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
ray at solarray.com
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 Underwriter’s
> 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
> peter.parrish at calsolareng.com  
> Ph 323-258-8883, Mobile 323-839-6108, Fax 323-258-8885
> 
> 
> 
>  
> 
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