Can we put a 6kW PV inverter onto a 5kW Multi if we set the PV inverter to 0.8 PF lagging so that it can only ever output 4.8kW of real power?
Is this a suitable way of having a little more solar on the ac coupled system and still keep 1:1?
What will actually happen to the reactive power?
I have currenrly only one MultiPlus-II 24/5000 but a Fronius Primo 8.2-1 with provisory freestanding 8,6kWo solarpanels and facing the same issue.
Yes, it works.
However, BEFORE you connect the Solarpanels, the MultiPlus-II must work correctly and setup to accept PV on ACout. Then connect the Fronius and let ur sync qith the MultiPlus-I. The go into the settings of the Fronius and limit the output power.
However, the MultiPlus-II has 5000VA but only 4kW. My one show clearly an overload ans shutdown if the Fronius is setup to more then 4kW and you have not a steady load on it.
Michelle,
I am not using Fronius. I am using Enphase. It is a lot easier with Fronius as you can enter the PROFI menu and go to the setting "Manual Power Reduction" and set your Fronius 8.2 to maximum output of 4kW (or whatever you like).
Unfortunately with Enphase I am unable to limit the power reduction with the grid profile. A 355VA micro inverter will output 366VA if there is enough irradiance. I am trying to find out if I set 0.8PF so that it can only ever output 293VA of real power is an acceptable way of derating the micro inverter to meet the 1:1 rule.
Additionally, I am trying to find out what affect (if any) this will have aon any of the components, e.g. more audible noise
Thank you
Michelle,
I see what you are saying. So we really need to keep to both limits when deciding 1:1. Both the VA limit and the W limit.
So a MPII 8000 can only have 6400W of AC coupled solar connected to it? I was under the impression that it would frequency shift to regulate this?
If yes, then of course frequenzy shifting step in. The problem occur only if you have a heavy load, the Fronius produce maximum and then you switch off the load.
The Fronius would try to press the 8,2kW into the Multiplus which support only 6,4kW. Of course, yoz should not charge the batteries to 100% because it should take over a very short term some current.
I have overdimensioned my solarpanels, that I get even in the Winter a decent amount of energy, even if it is only 50%, but it will reduce the usevof a GenSet enorm
The documentation highlights why you should adhere to the factor 1.0 rule. Potential damage from spikes should be your biggest concern and it explains it quite well.
The sizing is also quite well covered. If your array is oversized, the inverter size applies.
