pv system connected to sub-panel

[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

[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.

[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]

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.

[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]

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.

[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).

[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?

[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.

[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.

[J.P.M.]

yes, next year, to the revision.

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 ?

[Jest Waitn]

I don't understand your plan at all. Is your permit and interconnect agreement with your utility for 3 kW? Are you intending to pull another permit and revise the interconnect agreement for the expansions you are talking about?

yes, next year, to the revision.

[sensij]

if there is an 'issue' with over-production, it should show on the 3kw system. i will then have to re-configure it as a string system. the distance to transformer won't change. i won't run dc beyond the array site.

I don't understand your plan at all. Is your permit and interconnect agreement with your utility for 3 kW? Are you intending to pull another permit and revise the interconnect agreement for the expansions you are talking about?

[sensij]

Thank you for that. I noticed the exception for devices listed for continuous operation @ 100% of it's rating, which makes me wonder how many if any breakers out there are rated for this.

Eaton sells them 70 A and up. Not generally applicable to residential systems.

[SunEagle]

the MEP-002A 5KW military generator produces ~10kw at sea level. 5kw rating is for highest point on earth (thinnest air). i had this one tested at 9kw resistive load before buying.

I see that the diesel generator will output 120v single phase 2 wire, 120/240 single phase 3 wire, as well as 120/208v 3 phase 4 wire. Interesting design but it does provide power for a multitude of different voltage loads.