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Sample grid for a grid tie inverter - How?

Hello, I have a small grid tie inverter and I am interested in its operational behavior without any influence of the grid itself. How do I isolate grid so that the load bank I am planning to use doesn't get any of its power from grid nor the grid tie inverter feed power into grid while this is happening?

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This is something I am considering -

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As most of these grid tie interfaces often work by keeping the voltage higher than grid to become a current source, I am wondering how would it turn out with this kind of arrangement. Regards.

Reply to
Cdc
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The correct behavior of one of these things to a no-grid condition is to not turn on their output. I think connecting to the grid through a 1M resistor counts as "not connected".

_Any_ grid tie interface must, one way or another, work by keeping its voltage higher the otherwise-natural voltage of the grid. It works better to have it supply a current that's in phase with the voltage it sees, but your explanation is theoretically correct.

Disconnect the grid, and the converter is lost.

Now, there is no reason in the world that a grid-tie inverter couldn't be _featured_ such that it could be switched to a mode where it just plain supplies stand-alone 120VAC -- that's what modern "inverter" generators do. There are a whole bunch of practical safety considerations that make this inconvenient, but it could be done.

_Finding_ something that does this is left as an exercise to the reader

-- I have no idea if there's something like this on the market, for the afore-mentioned practical safety reasons.

--
Tim Wescott
Control system and signal processing consulting
www.wescottdesign.com
Reply to
Tim Wescott

Most GTI's try to wobble the frequency to sense if the gird is up. Your schematic will cause the inverter to go offline. It may even think that its part of an Island and the anti-island function will trip. Best thing to do is get a rock solid 120vac source. But that?s hard to find, maybe a xantrex prosine would work. You only need the frequency to be off a little for the GTI to go off line. You might want to look here

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Cheers

Reply to
Martin Riddle

Well, seeing as how grid tie inverters are required to shut down on loss=20 of grid voltage the goal may be very challenging. BTW there are obvious=20 safety reasons for this behavior.

Reply to
JosephKK

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