Smart Transformer requirements for integration in distribution grids and power quality improvement

The Smart Transformer (ST), a power electronics-based transformer, allows DC-distribution, reactive power control, storage integration, and meshing networks. These features are needed to avoid or defer infrastructure investment and are normally possible with the installation of single devices. The ST is a global solution but it represents also a new object for the power system, and it does not have any reference rule for its installation in the grid. This paper wants to show the results from the joint work of Kiel University, SP Energy Network and WSP, to determine the connection rules that a ST shall respect in the distribution grid. Furthermore, ancillary services, such as current and voltage harmonics compensation, are described in this work, to demonstrate the control capability of the ST in the grid.