question

tnt369 avatar image
tnt369 asked

Problem with two Quattro in parallel. Sometimes instable.

Hello to all,

I have a problem with two Quattro. As soon as they run in parallel on the mains, the two inverters sporadically " oscillate ". They then make a loud humming noise and then switch off very briefly and then on again. Then it goes on again for some time without problems until it starts again.

With only one Quattro, the system works without any problems.

It also works without problems with both Quattro when the grid is switched off (off-grid).

The effect only occurs with parallel operation on the grid.

The AC and DC cabling is symmetrical (identical cables and cross-sections).

The AC and DC currents were measured and are almost identical/symmetrical (+/- 1-2 %).

The Quattro were parameterised with the MK3 via Quick-Configuration (network: Europe, as I live in Spain). Same type and firmware (updatet to newest).

It seems that the Quattro build each other up on the mains and then switch off briefly for safety. For a short time, very high currents (> 100A) flow on the DC side with only a low load.

I have already exchanged master and slave. Without any change. The problem persists.

No error message is displayed on the CCGX.

Can anyone give me tips on how to solve the problem?

Thank you very much!

Greetings from Spain, Thomas


211201 PV Stromlaufplan.pdf

MultiPlus Quattro Inverter Chargergrid parallel
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3 Answers
tnt369 avatar image
tnt369 answered ·

Anyone have an idea how I can solve this?

Maybe it's the grid? What is the grid password so that I can adjust the grid parameters?

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tnt369 avatar image
tnt369 answered ·

Okay it is solved. Reason was the LOM function. With only one unit it was ok, but with both units there was a problem with the grid. Switched off the LOM detection and the system works stable.


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sgrigor1 avatar image
sgrigor1 answered ·

I have the exact issue with two parallel MultiPlus-II. Disabing the LOM detection solved the issue but it's not safe. We need a solution to this issue other than buy a 500euro anti-islanding device. Victron cleams that the device are confomed with VDE-AR-N 4105 for grid protection.

Anyone has any idea what could be the issue?

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