[RE-wrenches] Anti-Islanding Explanantion

[Michael Welch]

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
>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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>
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