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!