http://enphase.com/wp-uploads/enphas...tions_M215.pdf
Here is an Enphase doc that shows the voltage drops calculations.
Enphase microinverters do not like that big of voltage drop.
Luckily I was about 130’ away not as far as you going.
If there is too much voltage drop the micro inverters will think the grid is unstable and shut off wait 6 min and check again if the grid is back.