[RE-wrenches] Smart grid grid-connected compatibility

[Kent Osterberg]

Doug,

Enphase has suggested that solution and its a good one if the utility is 
cooperative. Of course, they are under no obligation to be cooperative, 
or to remain so. And unfortunately it looks like all the neighbors' 
meters being served by a common transformer, and maybe even more beyond, 
also trip the inverters off.

Enphase routinely describes the signal of that TWACS creates as changing 
the line frequency, but that is simply not factual. The frequency does 
in fact remain 60 Hz and the rms voltage is virtually unchanged as well. 
The waveform is distorted near the zero crossing, for about 8 or 10 
seconds, while data are sent. I managed to capture the event with a 
scope and the waveform distortion is probably well less than 2% and much 
less than the distortion inverters are to allowed cause.

Kent Osterberg
Blue Mountain Solar, Inc.
www.bluemountainsolar.com
t: 541-568-4882

On 7/9/2012 3:52 PM, Doug Wells wrote:
> Kent,
>
> I went through a similar situation with an Enphase system.  With a little discussion we decided that the easiest change is on the Utility side.  We encouraged the utility to put all solar systems with Smart metering on a different schedule.  Now the solar residence is only pinged at night when the frequency shift wont cause the inverters to drop out.
> I wonder how many string inverters are doing the same thing but go unnoticed.  The Enlighten graphs make detection of this event very evident as it looks like a huge crash every day at the exact same time.
>
> Doug Wells
> The Solar Specialists
> Morrisville, VT 05661
> (p) 802-223-7014
> (c) 802-498-5856
> www.thesolarspecialists.com
>
> _______________________________________________
> List sponsored by Home Power magazine
>
> List Address: RE-wrenches at 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
>
>
>