kalle01 avatar image
kalle01 asked

Need help to design a three phase battery inverter system under German conditions with VDE 4105

This is a drawing of my "powerplant". Except for the part with the Ouattro Inverters, I have already realized everything:

Black normal operation:

In normal operation, the solar system feeds the battery charger and the battery is charged.
At night, the battery is discharged via the same path.
PV and battery can be switched off by NA if malfunctioning.

Red are the actions in case of power failure:

The network is disconnected by a large contactor. (How to do that exactly, I have to find out)
Due to the power failure, the two contactors open from the NA protection
The voltage or current on the supply line of the NA protection breaks down.
The battery WR registers this and activates DC out and the power reduction of the PV to 1/3 power = 27.6 kW
The NA protection registers a correct voltage / frequency and opens the contactors for the PV system
The PV system starts up again and supplies power to the battery and house

Everything seems correct, but is that correct under VDE AR4105?

What is missing, what else needs to be considered?
Please your comments!

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2 Answers
mose avatar image
mose answered ·

Unless otherwise needed features, I would advice you to consider using six MultiPlus-II 48/5000/70-50 instead of your three Quattros 10000.

1) All needed components for VDE AR4105 conformity are already build in

2) It's a bit cheaper

3) You do not need any "unusual" circuits, so every normal electrician should be able to wire a secure setup without additional knowledge

I built a similar but smaller setup some weeks ago. Works like a charm.

See the picture attached for my Three-Phase-Setup. The plan is not quite polished up yet. It's missing the connection of the CCGX to DC-Distribution. Also it does not show the required wiring for communication - only 230VAC.

The OT40F4xx switches are not required. They provide the possibility to switch the loads to "grid-only" and completely disconnect the PV+ESS setup for maintenance or in case of a problem.

Please also read

(To view the image bigger, just open it in a new window/tab by using right click)

plan.png (299.0 KiB)
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kalle01 avatar image kalle01 commented ·

Thank you for your plan. It took me some time to understand why you build the circuits the way you do.

In my case, this does not work because of the VDE regulations for larger installations. There, a central "NA system protection" is a must. So I have to integrate the batteries into the existing "NA system protection" of the solar power plant.

The question is: Does my wiring diagram comply with the VDE regulations?

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kalle01 avatar image
kalle01 answered ·

Thank you for pointing out that double is cheaper!
Can you post plans or photos of your accomplishment so I can imagine how you did it?

Thanks again

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mose avatar image mose commented ·

Your "Answer" should be a comment on this kind of community system (similar to StackOverflow). I've updated my previous answer to add a plan.

I would be thankful if you'll upvote and accept the answer if helpful. :-)

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