I'd like to wire a battery-less grid-tie inverter (GTI) into my barn, but in a way that it does not put any energy back into the grid, and only powers my local loads and dump loads, and only when the sun is shining (no energy storage).
I have grid connection to the barn, but I do not want to use it to power my loads.
I do not want to do AC coupling, because of the cost of another battery-based inverter, and of course the battery bank, I don't need there.
So, I need a device that would hook up between the grid and this GTI, and would only provide a voltage/frequency reference waveform for the GTI to monitor and operate from. This device would couple the GTI to the grid in a way that only one-directional flow of energy is possible, from the grid to the GTI.
Looking from the grid side, this device would look like a normal load, and it would have a fairly large impedance so that it is only a small load to the grid, say 50 W or less.
Looking from the GTI side, this device would need to have very large impedance, and some other "check valve", to disallow the GTI to run any energy into it and into the grid (all inverter current needs to go to my local/dump loads connected between this device and the GTI). At 60 Hz this probably means a very large resistor or inductor, or a very small capacitor, or some combination of these.
Without regard to this set up violating or not any grid-tie rules/code:
Does anyone know of a simple device that may be used to generate a reference signal for the GTI using the grid, preferably some off-the-shelf unit?
How about any other simple ways to accomplish what I am trying to do, using the grid since it already contains a clean reference waveform and no additional waveform generator is needed?