How do Grid Tie Inverters know if the grid is there?

[miogpsrocks]

How do Grid Tie Inverters know if the grid is there and its not solar power generated from another micro grid tie inverter also on the property?

How can they tell its the real grid producing the power?

Thanks.

[SunEagle]

If you live in the US then the grid has a few values (impedance, voltage, etc.)that a UL listed inverter can measure and tell if it is tied to the grid or not

[miogpsrocks]

If you live in the US then the grid has a few values (impedance, voltage, etc.)that a UL listed inverter can measure and tell if it is tied to the grid or not

What about if my house is running on backup generator? Can the solar panels help out the generator or will they refuse to turn on?

[SunEagle]

If the inverter is grid tied then a generator usually will not produce the required values to turn it on. So no solar power will be generated

[solardreamer]

What about if my house is running on backup generator? Can the solar panels help out the generator or will they refuse to turn on?

If you have an inverter generator then it will activate grid-tied inverters but not for long. One reason is that generators will get damaged or trip because they cannot absorb excess power from the grid-tied inverters when there is not enough loads.