Grid tie equipment for off-grid use

[elnav]

The money is in grid tie so this is wher new developments are found.

I am wondering if anyone here has had experience with circumventing the anti islanding feature by external means. Altering the software or mangling the hardware is not an option since it would void the waranty.

Anti islanding means the grid tie solar or wind system shuts down when the grid goes down. Because so much R&D is directed into this type of equipment In many cases it has features not found in the older technology. Grid tie means you can add units in a modular fashion because they are designed to automatically synchronize with each other.

It also means the inverters deliver utility grade pure sine waves. Meshing wind and solar was more complicated with the older technology because of how the controllers work. When both are grid-tie it is less complicated. Back up storage in batteries for windless nights is somewhat more expensive.

[chowan]

Never had to work with grid tie equipment but by circumventing do you mean

that it could feed back into the grid if the grid went down?

and is this for a non grid tie purpose? (oops sorry reread the title)

could a small pure sine 220 inverter be used to trick the inverter in question into thinking it is conected to grid

[elnav]

Chowan wrote: could a small pure sine 220 inverter be used to trick the inverter in question into thinking it is conected to grid

That is essentially what I was asking. So far the ‘experts’ are split evenly as to yes or no it will work. The thing is when I synchronize larger inverters in big power installations it does work so in theory it should work.

The question experts have raised so far is that somehow the grid tie inverter would suck power from the little unit. Or at least thaat is how they phrased it. Trouble is I do not have a spare $7000 to buy stuff to experiment with so I was wondering if anyone had already tried this.

For synchronizing bigger installations a clock signal is connected to all the units via a data cable with RJ-45 connectors.

Where the wrinkle creeps in is when the big inverters pump out more power than is consumed. It automatically raises the voltage to make current flow ‘uphill’ to the grid which in this case is a tiny inverter. The question becomes what does the IGBT’s do when the voltage gradient is reversed across the device. At some point they do explode. In mis matched phasing they tend to get very hot then the copper in the heat sink gets molten. I have scraaped enough melted copper out of cases to know what that looks like. <smile>

Naturally none of the manufacturers will provide schematics

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