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pletexmatt16 avatar image
pletexmatt16 asked

AC PV in an off-grid mode of ESS

Hi,

I'm using a single-phase system equipped with 800W Multiplus 24/800 set as ESS and ET340 energy meter which measures grid exchange on L1 and PV inverter on L2. I use 500W third-pary (not Fronius) grid-tie inverter. I see that it is possible to set (in remote console) and connect PV inverter (third-party) on AC out of the Multiplus and I tested this and it works very well when the system is in grid-connected mode.

When the sytem is in the off-grid or islanded mode (inverter mode of Multiplus), PV inverter as an unit dissapears from the schematic on VRM Portal. It seems that energy meter is not measuring it and it is not present in the system. Based on my knowledge PV inverter is grid-tie and should work since the Multiplus is a grid-forming unit that regulates frequency and voltage. Furthermore, when installing ESS assistant on a Multiplus, I did check that there is a PV inverter and set nominal inverter and PV array power. I'm aware of Factor 1.0 rule and power frequency shift that Multi is performing in the case od excess power.

My main question is, is it possible to use AC PV on Mulitplus output when the ESS is in off-grid mode?

ESSoffgridAC PV Coupling
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2 Answers
pim57 avatar image
pim57 answered ·

Yes that’s possible.

your PV inverter needs to support the sunspec protocol.

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pletexmatt16 avatar image pletexmatt16 commented ·

Thanks for the answer. Do you have any further info which manufacturer's inverters support this protocol? Does Fronius inverters suport this protocol? Furthermore, if I acquire such inverter that supports sunspec (not Fronius), will it be visible in Remote console?

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Duivert NL avatar image
Duivert NL answered ·

hi i think the problem is that your et340 doesn't get power when you disconnect grid because it uses L1 to power itself, so L2 measurement shuts down and your pv measurement on ac out also


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