03-25-15, 06:48 AM | #1 |
Steve Hull
Join Date: Dec 2012
Location: hilly, tree covered Arcadia, OK USA
Posts: 826
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Use of grid tie PV when grid is down
I understand that grid tie PV systems do not operate when the grid is down. Logical to prevent back feed into the system killing a worker of they are on the lines.
Apparently, the inverters, string or micro, sense 50 or 60 Hz current at 240 V and cut off the inverter if that is not present. That said, can you turn the system off (transfer switch) turn on a small generator to "trick" the inverters into thinking the grid is still there? I know that it would now be necessary to use a dump load to rid the system of excess power. I can easily construct 240 V dump loads from oven electrical elements (2 kW each). Saw such a system when I was recently out of country. Problem was I did not speak the language and could not communicate with the builder (no translator present). The dump load was actually a set of hot water tanks with resistive elements. Steve
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consulting on geothermal heating/cooling & rational energy use since 1990 |
Tags |
emergency use, grid tie, pv system |
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