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Dragos avatar image
Dragos asked

ESS does not work properly (Romanian Grid code) - 3-phase installation

Hi, All.

I would like to ask for your help on the following installation and setup. I have been fighting with the setup for more than 3 days and no outcome. I was helped by our forum colleague (Andrew - Ponzoa) a lot during these days since he is very experienced, but we have not managed to make it work as expected. A big Thank You and my deepest appreciation for your help and I do hope you can continue helping me fix this. :)

Guys,

I have 3 x MP II 10000W/48V, 1 x Fronius Symo 10-0-3 and 8 x Pylon US3000C, 1 x Cerbo GX. They have all been updated to the latest firmware versions, including the Fronius.

Fronius is installed on the MPs output and configured to run in the ESS on the output of the MPs. Fronius country code set to MG50, although it turns back to International 50Hz and I was told by Andrew that it is fine, because it works.

Everything perfect until the Fronius PV inverter starts to produce more solar power. If the production is low (like a few hundreds watts), there is no issue, this is what I noticed.

So, MPs synchronize with the Grid (setup up for Romanian grid code), connection time set to 60s, and Fronius to 120s (reconnect time). After Fronius synchronizes as well and starts the energy production, the MPs disconnects from the mains (grid) and Fronius reboots. And it happens like this in an endless loop. If I disconnect the grid breakers (switch off the breakers on the AC Input of the MPs) and restart the Fronius inverter, everything is just fine. The batteries are being charged and the house loads are supplied (house loads all connected to critical loads output AC1). So, it works correctly as in an off-grid system, but as soon as I connect the grid and the Fronius inverter starts producing power, the MPs get disconnected from the grid. But, I do not get any errors and I do not know the reason for getting disconnected. This behavior gets me crazy and worried at the same time because this is the reason I purchased these MPs.


Do you have any idea of why this happens?

@Guy Stewart (Victron Community Manager) may I ask for your help? Can you help me, please?

I attached a few snapshots from the Remote Console.

Thank you in advance.

All the best.

Device list.JPGESS config.JPGMain page.JPGPV Inverters.JPG





ESS
device-list.jpg (44.4 KiB)
ess-config.jpg (42.7 KiB)
main-page.jpg (35.4 KiB)
pv-inverters.jpg (25.9 KiB)
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Alexandra avatar image Alexandra ♦ commented ·
@Dragos

Check the system grounding and earth.

Bothe from panels/fronius and the rest of the system.

Is there any voltage between N and E?

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Dragos avatar image Dragos Alexandra ♦ commented ·
Grounding is fine, Alexandra. Thanks.
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mjs500 avatar image mjs500 commented ·

are you setup as in grid or off grid ? as not showing ac in 1 voltage x3 ?

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seb71 avatar image seb71 mjs500 commented ·
Read the description. On-grid. And it works, but only as long as AC-coupled PV Inverter does not produce a lot.
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Dragos avatar image Dragos commented ·
Another issue I have just experienced is that if I disconnect the VE Bus cable from the Cerbo GX and connect it to the laptop via the MK3 and switch on the mains, they synchronize just nicely. But after a while I get the Low Battery LEDs On for all MPs. If I disconnect the VE Bus cable from the MK3 and connect it back to the Cerbo, after a few seconds the Low Battery LEDs switch off and after about 20s the mains get disconnected. The mains will only connect back if I remove the VE Bus cable from the Cerbo GX. Could it be a firmware issue of the Cerbo GX? I am running the latest 3.01 version. Thanks
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seb71 avatar image seb71 Dragos commented ·
Low battery LEDs might be because without a connection to Cerbo, there is no connection to the Pylontech battery. Just guessing, since I do not have Pylontech batteries.


What are the L1, L2, L3 voltages (from grid)?

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3 Answers
vicens avatar image
vicens answered ·

Provablemente el fronius cuando injecta a la red, debe de aumentar la tension que se sale de parametros del codigo de red, y los inversores deben de rechazar la red por tension alta. Cuando mas se injecta mas sube la tension en la linea de red?

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Dragos avatar image Dragos commented ·
Thanks for the answer. I don't think this happens. The phases voltage is within the range. I believe there is something wrong with the Cerbo GX firmware. The latest one. 3.01.
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seb71 avatar image seb71 Dragos commented ·

I believe there is something wrong with the Cerbo GX firmware. The latest one. 3.01.

I don't know of any such issues with v3.01 (this does not mean there might not be), but you could try the beta firmware (latest is v3.10~32) to see if there is any difference. Easy to test if it solves your issue or not.

Or you could also try a previous official release (such as v.3.00). But again, I don't know about any such known issues.

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Dragos avatar image Dragos seb71 commented ·
Thanks. I will downgrade to 3.0 tomorrow.
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seb71 avatar image
seb71 answered ·

Everything perfect until the Fronius PV inverter starts to produce more solar power. If the production is low (like a few hundreds watts), there is no issue, this is what I noticed.

Did you tried limiting the feed-in power (in Cerbo ESS settings) to see up to which point the Multiplus inverters disconnect from grid and Fronius PV inverter reboots?

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Dragos avatar image Dragos commented ·
No, I have not tried, but I believe it has something to do with the Cerbo. It makes me think why after connecting the VE Bus from the MK3 back to the Cerbo (mains ON) after aprox 20s the mains go off. If I disconnect the Cerbo and connect back the VE Bus cable to the MK3 or maybe leave it disconnected, the mains will be again ON. This is crazy, is it not?
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seb71 avatar image seb71 Dragos commented ·
Without the connection to Cerbo, I think ESS is disabled.
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Dragos avatar image Dragos seb71 commented ·
You might be right. I did several tests today, but no success. I downgraded the Cerbo GX firmware from 3.01 to 4.0 and then to 2.94. The same behavior. I tried to limit the inverter, the same issue. I changed the electrical scheme in order to make it the simplest one, the same. the last thing I will do before giving up would be to downgrade the Multis from 506 to 505. One of our forum colleague has this configuration: 505 on Multis and 3.01 on Cerbo GX. If this does not work, honestly I am out of any ideas.

Thank you.

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seb71 avatar image seb71 Dragos commented ·

I tried to limit the inverter

What exactly did you limit?


I changed the electrical scheme in order to make it the simplest one

What did you change?

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ponzoa avatar image
ponzoa answered ·

Can anyone confirm these serial numbers are compatible. I can't see why they shouldn't be, but just in case.


1693231922698.png


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