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ron-h asked

Multiplus II in 3 phase configuration

I have a lot of questions about how to AC wire the Multiplus II in a 3 phase configuration.

Information about the DC side and how to put the Multplus II in 3 phase mode is clear.
Could also see in a list of Netbeheer Nederland the Multiplus II is an allowed device on the grid.

First question is the gridcode, what gridcode should I select here in the Netherlands?
Somewhere here I found an old post how explains the Netherlands doesn’t have its own gridcode and you should use the German one instead, is this correct?

In case of grid outage the Multiplus II will this way be disconnected from the grid by its internal isolation relay.

How does this work in a 3 phase configuration in a situation that only one of the 3 grid phases is missing?

Will in this situation all 3 Multiplus II be isolated from the grid or only one?
And how long will it take the Multiplus II to make an hard secondary net by grounding the neutral (internal relay)?

Grounding the grid neutral if the 2 other Multiplus II don’t go in isolation mode, would give problems.
So simple question do I need in an 3 phase configuration an phase monitor / isolation relay between the grid and Multiplus II AC IN?

Mine grid connection is a 3x25A (C type fuse) and would add the Victron system in series with mine home fuse box.

How to protect the Multiplus II, circuit braker, fuse 25A (type B ?) and RCD (100/300ma type A/B?)

In off grid mode we do have a weak net, how to protect AC out?
This weak net will not trip a fuse is case of a short, inverter will go in failure mode.

Makes a RCD more sense, and should you prevent restoring normal situation after inverter fault timeout?

Is there any guideline/ regulation how to do this the correct way?

Are there special needs in ground resistance, I know in Belgium they check this if an EV charger is installed.

I hope someone knows the regulation in the Netherlands and can help!

Thanks,
Ron

3 phase
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Alexandra avatar image Alexandra ♦ commented ·

@Ron_H

https://www.victronenergy.com/where-to-buy

Use victron where to buy, then your location.

You can also use victron professional and create an account and learn more about three phase there. But you are right you need local knowledge of regulations.

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ron-h avatar image ron-h Alexandra ♦ commented ·

On Victron professional the 3 phase is only explained globally.
Grid isolation (3 phase) in case of one phase missing is not explained, do I have to test this myself?

We do have the NEN 1010 here, and they say regulation of ESS systems are in progress, so what is best effort here in the Netherlands?

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snoobler avatar image snoobler ron-h commented ·
When configuring the inverters in 3 phase in ve.bus system configurator, de-select "switch as group" - this will allow the inverters with AC input to continue to charge/pass-through AC input while the inverter on the missing phase will simply keep inverting.
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ron-h avatar image ron-h snoobler commented ·

Thank!

So be sure not to do that!

In case of de-select "switch as group" the multiplus with missing phase would activate its internal grounding relays and you then basic do short grid neutral with PE and there could be high current flowing from grid neutral to home PE.

There is always a small potential on grid neutral.

Do you know regulations in the Netherlands and could advice how to protect AC in and out?

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Alexandra avatar image Alexandra ♦ ron-h commented ·
As a side note you can't run ESS assistant with switched as a group off.
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4 Answers
ron-h avatar image
ron-h answered ·

Thanks!

The 3 Multiplus II will arrive end of this week, would be nice if I did know what I have to order for AC protection.

Did ask the dealer/ seller none response yet.

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ron-h answered ·

Found this document how to do this for the quattro.

https://www.victronenergy.nl/upload/documents/Datasheet-ESS-application-Quattro-48V-8-10-15kVA-NL.pdf

Multiplus II has the second AC isolation relays, so this UFR1001E monitor device is or isn't needed?

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ron-h answered ·

Seems to be difficult to simply tell there is an EN-50549-1 certification for the Multiplus II

https://www.victronenergy.com/upload/documents/Certificate-ESS-EN-50549-1-all-MultiPlus-II-(GX)-3k-&-5k.pdf

Still unclear how to protect AC in and AC out, and how to make the weak grid in off grid mode safe.

Any help would be greatly appreciated.

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ron-h answered ·

The 3 Muliplus II 48/5000/70 arrived today.

Battery will take until end of the month.

Grid code for the Netherlands select Europe EN50549-1:2019 or as mentioned here in the community the German VDE-AR-N 4105:2018-11 internal NS protection?

Does the Europe EN50549-1:2019 profile also activate the NS relays?

Only isolate the inverters from the grid (if the grid fails) by a separate NS relays would make it legal here in the Netherlands!

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Alexandra avatar image Alexandra ♦ commented ·

@Ron_H

Local regulation questions is not something most people can answer here.

Wiring standards are different all over the world.

Find a competent electrician.

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