Germany – grid protection settings according to VDE-AR-N 4105 and 4110

In Germany, the requirements for connecting BESS (Battery Energy Storage Systems) to the low- and medium-voltage grid are governed by two main technical connection rules:

VDE-AR-N 4105: Applies to low-voltage connections (≤ 100 kW, < 1,000 V AC).
VDE-AR-N 4110: Applies to medium-voltage connections (> 100 kW or ≥ 1,000 V AC).

These regulations define when and how grid protection relays must be installed and configured. Choosing the correct standard depends on the system's connection parameters, including voltage level, nominal power output, and installation location.

Selecting the right grid code

To determine whether VDE-AR-N 4105 or VDE-AR-N 4110 applies to your installation, refer to the official decision tree provided by the VDE FNN (Forum Netztechnik/Netzbetrieb):

https://www.vde.com/de/fnn/aktuelles/2020-05-04-entscheidungshilfe-4105-4110

This guide helps clarify which technical rule applies based on factors such as plant type, power output, and grid connection point.

Here is a simplified decision tree:

The screenshots below show more detailed decision trees from VDE FNN:

Note:

ABB:

For detailed information about configuring the ABB CM-UFD.M31 relay for Germany, see the following sections later in this manual:
- Germany – VDE-AR-N 4105 (Low Voltage).
- Germany VDE-AR-N 4110 (Medium Voltage).
Additionally, here you can find a manual that describes how to configure the ABB CM-UFD.M31 relay to comply with the German grid codes.

Ziehl:

For Ziehl settings, refer to the device manual.
On YouTube, you can view a video (in German) on how to set up the ZIEHL UFR1001E device: https://www.youtube.com/watch?v=Pany4lFwRro.