[RE-wrenches] utility line voltage issues

[SOLARPRO at aol.com]

Michael, Bill:
Our most troublesome areas are in older parts of So Cal (i.e. Pomona) with  
higher AC loads.  The ancient and undersized transformers just can't  
compensate for the sag, especially at the end of the line.  Edison WILL  replace 
the transformer after the DG customer and all of his fiends and  neighbors 
harass customer service for about two years... or when it  blows.  
The dream wrench org..... when we finally wake up and put one together I  
hope I'm still around. Right now CalSeia is just about the only game in CA 
town,  as far as Big Tent SOLAR  is concerned and I gotta believe herding  
cats would be a good deal easier.
Pat Redgate
Ameco Solar
PS Yes, I think it is time to find an attorney.... and there's a whole  
bunch of 'em in Sacramento.  But I also think it's a legitimate idea to  
rethink voltage bandwidth at the PUC and PA forums. I believe all of Michael's  
assumptions are low.
 
 
 
 
In a message dated 8/16/2009 10:42:54 A.M. Pacific Daylight Time,  
michael.welch at re-wrenches.org writes:

Please  check my math, I did it pretty quickly.

CA has over 450 MW of  distributed PV systems. At around, say, 4.5 average 
daily sun hours (it is  probably more, averaged over the state's systems), 
that would be 540,000 MWh  each year.

If the utilities are dropping out of spec, say, 1% of the  time, that's 
5,400 MWh of loss each year. At 15 cents a kWh (the average is  probably more) 
that turns out to be $81,000 worth of losses to us.

That  does not seem like a whole lot , but the number will grow as fast as 
PV  installations are.

Maybe it is time for a class-action lawsuit against  the utilities. Or time 
for the dream Wrench organization to file with the CPUC  for relief in the 
form of stricter utility specs, or petition UL for looser  inverter specs.

One question, why are inverters required to drop out  for out of spec 
voltage and frequency? It seems to me that the UL requirements  are overly 
limiting in that regard. I mean, if the utility can do it with  their huge plants, 
why can't we with our little ones?

William Korthof  wrote at 10:06 AM 8/16/2009:

>I'm beginning to wonder if the allowed  voltage range for grid-tie 
inverters (+/-10%) is too sensitive in some  networks and contributes more harm 
than benefit. This is close to  home.
>
>We actually have a significant number of customers who've  had trouble 
with grid voltage causing their systems to go offline at various  times. I 
think most or all are SCE  customers.



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