On 4/11/2011 7:26 PM, Peter Laws wrote:
> On Mon, Apr 11, 2011 at 15:43, K8RI<k8ri@rogerhalstead.com> wrote:
>> 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.
That would not be in the power companies best interests. Those things
cause them all kinds of headaches and "book work"
>> 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
>
> You're not up-to-date on the latest in the solar industry.
yes I am. That's why I complain. They have taken the most complex and
least user friendly approach to disconnect by shutting the inverter down.
> Most
> grid-tied systems these days have no batteries (because they reduce
> system efficiency). The system generates power while the sun is up,
If you are lucky. The payback map doesn't even list MI.
> offsetting part, all, or more, of your consumption. At times when the
> inverter doesn't cover 100% of your load, you pull from the grid. If
> you're lucky, you have net metering so you get credit for any excess
> you put into the grid.
>
Which is nice but not a necessity and would not be my primary reason for
solar in the first place.
Any system I put in has to be capable of at least powering my house for
at least 24 hours.
> Regardless, whether there are batteries or not, UL requires that
> grid-tied distributed generation systems (solar, wind, hydro,
> whatever) disconnect from the grid within a cycle or three (forget the
> actual spec).
It would have to do that any way for self preservation and a transfer
switch can do that.
If my transfer switch did not operate can you imagine how long my
generator would last trying to power everything in my neighbors homes?
> This is to protect utility workers and the integrity of
> the grid.
Disconnect is fine. I have to do that even with a generator. OTOH the
way they do it, to me defeats the entire purpose of of why I would
install solar. I need a backup system. Although the money back from the
utility would be nice, it would not be my primary goal. As I would be
using large batteries as storage, I'd have to develop a work around
plus another inverter to keep AC power in the house during one of the
many failures. Such systems are advertised but I've never had the
chance to view one or check it for RFI.
I want a system that will provide substantial power and back up the AC
system for at least 24 to 48 hours. Yes, I know how much that costs.
I'd prefer independence, but back up would suffice.
The major problem with these systems is cheap inverters and RFI. There
are good systems and many not so good. Fortunately not many of the not
so good are next door to hams. OTOH we have had posters with noise
problems from nearly a mile away. The inverters at the PV panels
require some pretty good protection from lightning. Transistors are
fragile, and it wouldn't take much to turn a quiet system into a real
noise maker.
My tower has been up since 2001 and taken 17 verified direct strikes.
How many it actually took I have no idea. For the first 5 years it
averaged 3 a year. Year # 6 it took one hit and none since then...that I
know of. I wonder how well roof mounted inverters (at the panels) would
have survived that and if they would have kept producing clean power?
OTOH that may not be much of a concern as they have outlawed (at least
for the time being) solar installations in our township due to
complaints caused by reflections from the last system installed.
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