3 phase solar panel system for workshop. Any suggestions?

[chefdecuisine]

Hi there,

I am planning to build (DIY) a solar panel powered setup with 10kW for our workshop that feeds back into the grid (export into the electricity distributer's network). The tricky part is that I need to invert into 3 phase power. I have been looking for any diagram showing which parts I would need and how they are wired together but was not able to find anything.

Is there anybody who could help me by pointing in the right direction please?

Here are some remarks as well as some background information of what I found out so far

- I have been told that either a 3 phase solar power inverter or microinverters will do the trick. What is the advantage / disatvantage between them?
- We are living in New Zealand and it needs AS/NZS 4777.1 compliance certification for the inverter and AS/NZS 5033 for the solar panels.
- I am importing 5 containers each year from China and would be able to get all the parts from there. Any recommendations on a particular supplier?

Many thanks,

Stephan

[Mike90250]

You will need either a 3ph inverter, or 3 inverters that can be interconnected for 3 phase use. Not sure what the source would be for a small one. Schneider Electric makes large trailer mounted 3 phase gear, maybe SMA makes smaller ones.

https://www.google.com/search?q=3+phase+solar+power+systems

[chefdecuisine]

You will need either a 3ph inverter, or 3 inverters that can be interconnected for 3 phase use. Not sure what the source would be for a small one. Schneider Electric makes large trailer mounted 3 phase gear, maybe SMA makes smaller ones.
https://www.google.com/search?q=3+ph...+power+systems

Thanks Mike. I understand what you are saying. I was also looking into using micro inverters which I can then freely reconnect depending on how busy one of the phases gets.

[inetdog]

What it comes down to is that either a string inverter or a micro inverter will synchronize to the line voltage and phase that it sees, so the standard way to get three phase GTI is with three inverters. And as long as your loads are balanced, there is no need for the three (or more) inverters to talk to each other.

However this does raise an interesting point in that three separate GTIs will have to be wired to three separate sub arrays of your panel farm. Otherwise they will fight while hunting for the MPPT point.
That (three phase from one DC input connection) is probably the only advantage of a single chassis three phase inverter (which I have not seen offered in consumer sized packages.)

Micro inverters certainly would give you more flexibility, but unless your POCO charges you a penalty for imbalanced consumption, I do not see a persuasive reason to move inverters from phase to phase.
Keep in mind that it could take the micro five minutes or more to re-qualify the connected utility power each time you switch between phase connections.

[Mike90250]

With micro-inverters, you better watch out for "Low Line (AC) Voltage" trip off's. 3 phase is 208VAC, standard USA household grid power is 240VAC. 208V may not qualify on the inverters, unless you actually get a 208V model.

[inetdog]

With micro-inverters, you better watch out for "Low Line (AC) Voltage" trip off's. 3 phase is 208VAC, standard USA household grid power is 240VAC. 208V may not qualify on the inverters, unless you actually get a 208V model.

The Enphase units seem to be configured for either 240V line to line or 208V line to line operation depending on which version of the AC harness you connect them with. Whether this also automatically takes care of the voltage setting, or whether there is a configuration switch change needed too, I do not know.

[Naptown]

see if this will work

http://www.fronius.com/cps/rde/xchg/SID-CE3F7CAF-3F4ED2E9/fronius_international/hs.xsl/83_13703_ENG_HTML.htm#.UysNDqhdWBo