pv system connected to sub-panel

[SWFLA]

The MEP-802a TQG has been released for some time now. Much quieter. You might be able to find an Acoustic Suppression Kit (ASK) yours. The technical manuals, parts manuals and such can be found at
steelsoldiers.com
great bunch of guys there too, for information and troubleshooting help
I have a mep-831a variable speed inverter. .2 gal/h love it.
planning on using a Schneider SW set up to load shave for starting heavier loads.

[Jest Waitn]

Probably not super critical, but if you're planning to base future system size increases 1 year's output of a 3 kw system, are you aware that system output can change from yr. to yr. based solely on weather variation alone ?

part of the problem most face with implementing a pilot system is due to revision. so many projects are NEVER implemented due to revision. they want a perfect pilot. dumb. the pilot is built as a basis for evaluation. i expect the system to perform well since it has for others. i learned today that virtual net metering is NOT offered by FPL and might NOT ever be offered (at least until customers scream for it). i learned this month that the micro-inverters might have difficulty providing electricity to the grid. so presently i am considering implementing a string inverter system next year. flexibility is the key.

[SunEagle]

part of the problem most face with implementing a pilot system is due to revision. so many projects are NEVER implemented due to revision. they want a perfect pilot. dumb. the pilot is built as a basis for evaluation. i expect the system to perform well since it has for others. i learned today that virtual net metering is NOT offered by FPL and might NOT ever be offered (at least until customers scream for it). i learned this month that the micro-inverters might have difficulty providing electricity to the grid. so presently i am considering implementing a string inverter system next year. flexibility is the key.

What information did you learn concerning micro inverters not playing well with the grid?

[sensij]

What information did you learn concerning micro inverters not playing well with the grid?

If there is a long run from the array to the grid, the voltage rise can cause problems (post 7 in this thread).

[Jest Waitn]

If there is a long run from the array to the grid, the voltage rise can cause problems (post 7 in this thread).

an on this, hopefully this problem won't present in this first effort. if it does, the micros will have to be swapped out for a string.

[inetdog]

If there is a long run from the array to the grid, the voltage rise can cause problems (post 7 in this thread).

But if you are only concerned with operating stability and not with lost power in the wire resistance, you can use a buck transformer configuration to reduce the apparent grid voltage at the micros.

[Jest Waitn]

But if you are only concerned with operating stability and not with lost power in the wire resistance, you can use a buck transformer configuration to reduce the apparent grid voltage at the micros.

this sounds like a patch. i might even scrap the micro-inverter approach and go with a string before finishing this first effort.

[SunEagle]

If there is a long run from the array to the grid, the voltage rise can cause problems (post 7 in this thread).

All that means is using bigger wire to reduce line loss and potential voltage issues.

Still if it was up to me I would go with a string inverter because it would be cheaper and reduce the number of failure points.

[Jest Waitn]

All that means is using bigger wire to reduce line loss and potential voltage issues.

Still if it was up to me I would go with a string inverter because it would be cheaper and reduce the number of failure points.

service cable is used up to the sub-panel. the array feeds the sub-panel with 12/3, due to the short distance.

i have already bought the micro-inverters and the cabling.

[bcroe]

But if you are only concerned with operating stability and not with lost power in the wire resistance, you can use a
buck transformer configuration to reduce the apparent grid voltage at the micros.

Has anybody actually seen that done? The equipment is here, but unused. I would be concerned that the buck
trans might raise the apparent line impedance enough that it refuses to run. Bruce Roe

[SunEagle]

service cable is used up to the sub-panel. the array feeds the sub-panel with 12/3, due to the short distance.

i have already bought the micro-inverters and the cabling.

Hopefully you won't see any issues and those micro's work for you. Keep us informed.

[Jest Waitn]

Hopefully you won't see any issues and those micro's work for you. Keep us informed.

i measured the plug voltage in house @ 125.3 tonight. tomorrow i'll measure @ the sub-panel. this is rural and the 'end of the line' on this service leg.

i measured the sub-panel voltage this a.m. @ 249vac even.

[ButchDeal]

i measured the plug voltage in house @ 125.3 tonight. tomorrow i'll measure @ the sub-panel. this is rural and the 'end of the line' on this service leg.

The grid voltage is not constant so you will need to measure them at the same time or at least a few times close to the same time.

[Jest Waitn]

Yes. Microinverters operate at line voltage (240 Vac), while string inverters can operate up to 500 Vdc, depending on panel selection and array design. The same power at higher voltage means less current. Less current means less loss.

i looked tonight at some string inverter specs. it seems that the 'ceiling' for 240vac is 264vac. the range is given 211v-264v. how is this different from the micro-inverter?

[sensij]

i looked tonight at some string inverter specs. it seems that the 'ceiling' for 240vac is 264vac. the range is given 211v-264v. how is this different from the micro-inverter?

If you mount the string inverter near your main panel, you can run the 500 Vdc the long distance with less loss and just have a short AC run.