*4.1. Cell-Based Grid Model*

The original medium-voltage grid of the city of Leoben is divided into 26 energy cells. Figure 10 illustrates the developed simplified cell-based grid model, where the 30 kV voltage level is shown in blue and the 5 kV voltage level in green. To clearly distinguish the two voltage levels, the 30 kV level is marked with the ending \_030 and the 5 kV level with the ending \_005. Since the 30 kV voltage level is not designed to cover the complete area of Leoben, not every cell has a connection to the 30 kV voltage level. The 110 kV voltage level of the Leoben substation was chosen as the slack node, so that the load flows between the 30 kV and 110 kV voltage level can also be analysed. The slack node thus corresponds to the energy node N10\_110. Since there are two 110 kV/30 kV transformers in the substation due to redundancy, both are also shown in the grid model.

**Figure 10.** Simplified cell-based grid model for the city of Leoben.
