A modified sine wave inverter + a grid tie inverter?

[eccerr0r]

If I had a solar fed grid tie inverter (GTI), a modified sine wave inverter, and a power outage occurred, what would happen if you disconnected mains, backfed the modified sinewave inverter (MSI) into house power, and hooked up the GTI to the output of the MSI, would it work?

Next thing is trying to charge the batteries using solar power, but that's another issue ...

[stj]

Re: A modified sine wave inverter + a grid tie inverter?

interesting question.
firstly the gti will try to sync to the invertor that isnt really sinewave - so maybe or maybe-not.

then you need to hope that the sine invertor doesnt take feedback from the output and start drifting down - that may not be too much of an issue if the gti can see the voltage still.

are you using an isolator from the street?
the whole point of gti's going down when the power is out is so you dont backfeed the street and potentially kill lineworkers

[eccerr0r]

Re: A modified sine wave inverter + a grid tie inverter?

Actually the regular MSI would be a bigger problem, they have no anti-islanding protection whatsoever and happily would try to backfeed the whole neighborhood :o
Then again, that should have been averted by disconnecting the mains (i.e. shut off the main breakers) so there should be no problem with that.

There's the other problem of trying to power both phases as the MSI is 1-phase - though this should be easily worked around with a high wattage autotransformer, Might not be efficient but no power at all is less efficient.

[stj]

Re: A modified sine wave inverter + a grid tie inverter?

well if your isolated from the street you can link the phases.

[eccerr0r]

Re: A modified sine wave inverter + a grid tie inverter?

true, though having that autotransformer there won't be a (large) burden if you reconnect to the grid whereas the link would

[sam_sam_sam]

Re: A modified sine wave inverter + a grid tie inverter?

This is an interesting topic will also watch this post as well