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@contesting.com [mailto:rfi-bounces@contesting.com] On
> Behalf Of Charles Coldwell
> Sent: Sunday, April 10, 2011 7:36 AM
> To: Allen Griffith
> Cc: rfi@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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