[RFI] OT: RE: solar problems

K8RI k8ri at rogerhalstead.com
Mon Apr 11 13:43:52 PDT 2011

On 4/11/2011 5:46 AM, Cortland Richmond wrote:
> If it's a deliberate phase bobble, that's a clever  way for power co's
> avoid having to pay people for their solar power.

They need to control phase, but there is no need for them to shut the 
inverter down in the line power is shut off.   The inverter system 
should have a transfer switch and immediately drop the  connection to 
the power line.
This allows the PV system to work off batteries as a back up.  This type 
of regulation completely defeats the back up ability of a PV system 
which is why I'd install one in the first place.  That I can get money 
back from the power company is great, but not if I still have to install 
a 15 or 20 KW generator that runs off natural gas or gasoline plus 
wiring it in with a transfer switch.

Although we are close to a good size city, the power lines run through 
woods, and we lose power at least 2 or 3 times a year for quite a few 
hours at a time.

I purchased a 9500 watt generator back in 2000 *after* they went on 
sale<:-))  That generator now has close to 200 hours on it is just over 
10 years.  I'm afraid I'd have to forgo the money from the power company 
as it'd take quite a while for the payback to cover the generator.  As 
it is the payback which is highly touted would take many years.

In another 4 or 5 years PV should be much cheaper but true sine wave 
inverters with enough capacity to run refrigerators, furnaces, and air 
conditioners are going to be pricey.

> Cortland
> -----Original Message-----
> From: rfi-bounces at contesting.com [mailto:rfi-bounces at contesting.com] On
> Behalf Of Charles Coldwell
> Sent: Sunday, April 10, 2011 7:36 AM
> To: Allen Griffith
> Cc: rfi at contesting.com
> Subject: Re: [RFI] RFI Digest, Vol 99, Issue 5
> <snip>
>> rid power drops ... or is crappy).
> Indeed, this the "anti-islanding" requirement of UL-1741 for inverters.  The
> idea is that the power company may have turned off the power intentionally

They should allow for transfer switches rather than turning off the 
inverter.  These things always seem to end up far more complicated than 
they need to be.

> to allow work on the line, so if your home generation system is still
> energizing the wires you could electrocute a lineman.

I run far more power into the house than most home PV systems are 
capable of generating and the power company has no need to shut down my 
generator.  Why can't they do the same if the phase gets out of 
tolerance instead of shutting down the inverter.

Here the regulations will not let you have a battery back up on the 
inverter if it's tied into the power grid.

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