Fronius IG120 Plus

[SRE]

I suspect this is a really stupid question but does a 3 phase inverter spread the load equally over the 3 phases? We're installing a 9.8kpw across the 3 phases shortly but obviously we want to keep each phase under 3.68kwp to keep within G83.

 

[mmccx]

Yes it does

 

[Sonic280674]

Ive had a call to have a look at an under preforming system which has an IG120 plus yet the design has put 10 panels of the 54 panel system on a different orientation. In my view doesn't all strings have to have the same value for this invertor to work efficiently? if so can I suggest they use a mpp tracker on the inverter?? ideas guys

 

[Worcester]

I suspect this is a really stupid question but does a 3 phase inverter spread the load equally over the 3 phases? We're installing a 9.8kpw across the 3 phases shortly but obviously we want to keep each phase under 3.68kwp to keep within G83.

Not all do .... It depends upon how they are contrsucted.

One oddball one is the eltek - its is basically three single phase inverters in a single box, so has seperate string imputs to each "phase"

As I say it is an oddball, all the others I know create an equal balance across the phases.

 

[Martyfox]

My understanding of the IG plus inverters is that the use the Fronius MIX concept. There are 3 power stacks, one per phase. The inverter starts up in the morning using the one with the least logged run hours, then the next, then the last one as power increases over 1/3 of the power output. The idea being that this means the stacks are running efficiently (top end of their output) and the run hours are kept to a minimum.

The downside to this is that phases are not balanced, and you never really know which phase you want to be using power on.

This is all done with 1 MPPT tracker.

I believe you can also set up to balance across phases, too, if you wish.

 

[SibertSolar]

Worcester is right about the Eltek 3PH units in that there are three MPP trackers (up to 3 DC strings on each), but the main unit itself has built-in functionality to balance the 3ph output. Any inverter with more than 1 MPP tracker is effectively more than 1 inverter from a DC point of view - it's what they do internally with the power that is relevant. The Eltek inverters don't simply output 1 MPP tracker's converted DC into AC onto a single phase, with no relationship between the 3 phases internally....