Yes, but Enphase Microinverters shut off, SolarEdge inverters shut off, for
just that reason. This makes them certifiable. They are probably the better
ones for my application.

You mentioned it was possible with more equipment. Can you elaborate? I want
to primarily be on the program, but when my grid goes down for any serious
length of time what more equipment would you recommend me considering that
both meets the code, made in Ontario and is tried and true, suitable for the
program. I don't want knock offs or copies, or offshore stuff. Must be
certified and meet the code, etc etc, and not so complicated it needs NASA
Satelite Engineers to approve my drawings.


Thanks





wrote in message
...
Tom wrote:
Thanks for commenting Jerry

Yes, all you say is the same here. All elements of the codes must be
followed.

So you are saying it is possible to be able to use your solar panels when
the grid is off?

At my cottage the grid shuts off for long times.

Thanks

Yes, it is possible, but takes more equipment.

Most PV systems take the simple approach to the requirement that they
not feed into a grid that is off and potentially electrocute a
lineman by simply turning off your system.

More expensive systems include sensors and relays to isolate your
PV system and residence from the grid if the grid turns off.



--
Jim Pennino

Tom wrote:
Yes, but Enphase Microinverters shut off, SolarEdge inverters shut off, for
just that reason. This makes them certifiable. They are probably the better
ones for my application.

You mentioned it was possible with more equipment. Can you elaborate? I want
to primarily be on the program, but when my grid goes down for any serious
length of time what more equipment would you recommend me considering that
both meets the code, made in Ontario and is tried and true, suitable for the
program. I don't want knock offs or copies, or offshore stuff. Must be
certified and meet the code, etc etc, and not so complicated it needs NASA
Satelite Engineers to approve my drawings.


Thanks

I have nothing to do with solar systems and what I know is based on
the research I did to decide whether or not such a system made any
sort of sense in my situation.

I did not find any system that would maintain power in a grid outage
that did not include some sort of backup power, i.e. either a battery
storage system or an autostart generator.

All the systems I found were integrated systems in that I did not find
anything you could add to an existing simple PV system and convert it
to one that would maintain power in a grid outage.

All I can suggest is an extensive web search to see if there is anything
on the market that meets your needs.


--
Jim Pennino

In article ,
wrote:

I have nothing to do with solar systems and what I know is based on
the research I did to decide whether or not such a system made any
sort of sense in my situation.

I did not find any system that would maintain power in a grid outage
that did not include some sort of backup power, i.e. either a battery
storage system or an autostart generator.

I think that's difficult to do, unless you have already converted to a
pure-DC system and have devices which can tolerate brownouts.

Solar-panel systems have a somewhat funky power-delivery curve. If
you try to draw more power than they can deliver, their output voltage
drops like a rock. For some sorts of loads (incandescent) this may be
tolerable. For surge loads such as motors, it's bad... the motors can
stall, or bog down, and may burn out. Some classes of load (e.g. many
switching power supplies) will start drawing *more* current as the
voltage drops, in order to continue delivering the required amount of
power to their load... and the solar panel's output voltage drops
further, current load goes up, voltage drops more... THUNK.

So, driving inverters or other variable loads directly from a
solar-panel array, without at least *some* stored energy to handle
spikes in load or drops in supply (cloud-over-the-sun) is a tricky
problem to solve, and I believe it's very likely to result in a system
which simply isn't reliable. If you're going to spend a hefty chunk
of money for one as a back-stop against grid outages, that probably
isn't a satisfying result.

On 8/20/2015 5:40 PM, Tom wrote:
Yes, but Enphase Microinverters shut off, SolarEdge inverters shut off,
for just that reason. This makes them certifiable. They are probably the
better ones for my application.

You mentioned it was possible with more equipment. Can you elaborate? I
want to primarily be on the program, but when my grid goes down for any
serious length of time what more equipment would you recommend me
considering that both meets the code, made in Ontario and is tried and
true, suitable for the program. I don't want knock offs or copies, or
offshore stuff. Must be certified and meet the code, etc etc, and not so
complicated it needs NASA Satelite Engineers to approve my drawings.


Thanks

Tom,

Yes, there are systems which can operate independently from the grid.
Typically they operate like a zero time switchover UPS - your house
actually runs off batteries and/or rectified and filtered AC, through an
inverter which generates the 60hz. But if you're talking 200A service
at 230V, you're talking over 45KW maximum drain. An inverter which
generates sine waves with that much power (not to mention the batteries
required to support it) is quite expensive (and generating clean sine
waves isn't all that efficient). Sure, you don't need it all of the
time - but you need to be able to supply the peak draw.

As Jim hinted - you have to isolate the output of your inverter from the
power lines, even though they both feed the same equipment. Otherwise,
when you lose power, your inverter is going to try to supply power to
the whole neighborhood. Not only would that burn out your inverter, but
it could electrocute someone.

That's a big reason most backup systems use diesel generators. They are
much more cost effective and will run as long as they have fuel
available. Plus they generate pretty clean sine waves. Switchover is
on the order of a few seconds; if that's too long one or more UPS's for
critical systems can keep power up for that short of a time.

--
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Jerry, AI0K

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