Quote:
Originally Posted by greglepore
I had a 9kv solar system installed recently. I have a preexisting 30kw water cooled generator with an auto switch. If it maters, the inverter is Smart Edge.
My concern is that the solar is tied into the mains at the gen switch on by taps into the utility side. What happens if utility goes out, but panels are producing? Do i have a brownout if load exceeds solar output as the switch still sees power? Or am I missing something?
Couldn't get a straight answer from the solar installers, just that "its ok'".
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The Solar
MUST be connected to the utility side of the transfer switch. When the utility power goes out, the solar will stop producing, per UL-1741
The issue is that the solar panels could backfeed the generator if they are on the house side of the transfer-switch. In other words, you are using 2kW and they produce 5, where does that power go? The grid tied inverters are not designed to modulate their output.
The systems we build are setup with AC or DC coupling.
With DC coupling, you are connecting the solar panels to the battery side of the inverter system. If the batteries go full and the utility power is up, they will sell power to the grid. If the batteries go full and the utility is NOT connected, the charge controllers will modulate the solar output down to your usage.
With AC coupling, we use a relay to connect the solar panels. When the utility is off-line, if the batteries go full we disconnect the solar panels. If the generator is running, we also disconnect the solar panels.