[RE-wrenches] Anti-Islanding Explanantion

[Peter Parrish]

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