Influence of voltage support by converter based distributed generation on the short-circuit power

This paper describes the influence of replacing centralised generation by distributed generation (DG) with a full converter (e.g. type 4 wind turbines, solar power) from a short-circuit power and a voltage support point of view. To allow investigating the influence the settings of the voltage support of the DG units, an iterative approach based on linear network calculations is used. Inherently, the short-circuit capability of these DG units is limited. However, it is shown that DG units can contribute to the short-circuit power of higher voltage levels to compensate (partially) for the short-circuit reduction that arises when DG units replace centralised generation. Additionally, it is verified that any increase of the short-circuit power is concentrated on the local grids where the DG units are connected. Other local grids are influenced far less. This allows to tune the voltage support settings based on the requirements of the high voltage grid, but to take into account constraints in the short-circuit power of the local grid.