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Micro-grid with MultiPlus II and Fronius Primo - causing flickering lights

Hi,

We built a new single-phase installation recently with the following components:

  • MultiPlus II 48/5000
  • Cerbo GX
  • 4x Pylontech US2000C
  • PV inverter Fronius Primo 4.0

Grid is connected to MultiPlus AC in, all loads and the PV inverter are connected to AC out 1, like so:

1648212167220.png

Grid metering is done by the internal meter of the MultiPlus, Fronius is connected via ethernet (zero feed-in with ModBus via TCP).

Generally speaking, this setup works really great, now we're getting to the last 10% of optimization, and the current issue is the transition from grid-parallel to micro-grid, which causes the following:

  • Error 105 on Fronius (AC frequency too high) when switching off the connection to the grid (Fronius restarts/recovers quite quickly though)
  • Flickering lights at certain load constellations while operating on micro-grid (e.g. Fronius delivering 2.5 kW and loads around the same value (oven + small toaster)

The flickering can be described as brightness oscillation around 1-2 Hz, as if MultiPlus competed with Fronius for the voltage regulation. If useful, I can upload a video later.

Parameters are set as recommended by the documentation (MG50 on Fronius, Frequencies set in the ESS assistand according to https://www.victronenergy.com/live/ac_coupling:fronius). Native Fronius zero feed-in works fine also. The documentation mentions "Q5 How can I get the Fronius firmware that improves flickering?", but the Fronius is brand-new and all firmwares have been updated, so this shouldn't be the point.


Any ideas and help is much appreciated :-)

Thanks

Multiplus-IIFroniusmicrogrid
1648212167220.png (43.3 KiB)
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6 Answers
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ips-ad answered ·

This has been solved in the meantime, by Fronius providing a downgrade to fro32071.upd. They said they are aware of the issue and will probably fix it in one of the next versions.

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popnic avatar image popnic commented ·

Just for info. Not solved in my case.

There is no firmware fix available for newest Fronius Primo. 2022 models does not accept firmware version fro 32xxx.upd anymore.

The latest and greatest firmware has some improvements but still not acceptable.


1 Like 1 ·
popnic avatar image popnic commented ·
@ips-ad

Thank you for telling us how you solve your problem.

I found that a same setup has same issue. I will contact Fronius.

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Rob Duthie avatar image
Rob Duthie answered ·

Hi


The latest ver fro33350 had fixes for MG50-60, but still has issues with flicking.

Regards

Rob D

NZ

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samer-abi-chaker avatar image
samer-abi-chaker answered ·

Hello,


Has there been any update on this since November? I recently updated my Fronius firmware by mistake and flickering became pretty heavy. My UPS's at home keep ticking due to the voltage change.


Appreciate the help.


Samer

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Rob Duthie avatar image Rob Duthie commented ·

Hi

Go back to the older version, stable ver is 32070.

Rgerads

Rob D

NZ

0 Likes 0 ·
mgstrad avatar image mgstrad Rob Duthie commented ·

Hi Rob

Would it be possible to get a copy of the 32070?

Steve

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Rob Duthie avatar image Rob Duthie mgstrad commented ·
send me your email address to raduthie@gmail.com
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poplargrove avatar image
poplargrove answered ·

We are having this issue too, only occurs in low generation situations when solar almost equals load. Install was January this year so I assume the downgrade is not possible. Is there anything in setting etc or an add-on to the mix to fix this? Also all our clocks (oven/microwave) run fast, and we have had 2 band new LED lights with drivers die, and our projector! Could this be caused by the pulsing/flickering? Or just a coincidence? Anything I could do to protect my electronic equipment in case this pulsing is causing issues as I don't want any more expensive appliances dying / lights dying?

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Rob Duthie avatar image Rob Duthie commented ·
Hi

As above downgrade the Froinus firmware to 32070

Regards

Rob D

NZ

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glipschitz avatar image
glipschitz answered ·

Does anyone have a copy of the firmware they can supply?

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Rob Duthie avatar image Rob Duthie commented ·
Yes
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Chris avatar image
Chris answered ·

I am curious if the same flicker issue occurs with other manufacturers string inverters - when using the frequency shift function.
I am guessing that its equally a symptom of the Victron method of switching between charging and discharging. Ive used Solis and didnt have an issue, would be interesting to see if with a SolarEdge inverter it behaves better.

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