Basic Considerations for Operation and Protection of Modular Grids with Grounding Transformer

Abstract:
The project FlexNet-EkO aims to implement a modular grid, a power-electronically decoupled part of the distribution grid, at low voltage level. Decoupling is realized by a so-called power electronic grid interconnector. This paper describes the use of a grounding transformer to supply single-phase currents and its influence on grid operation and protection. The impact of dq reference frame current limitation in combination with a grounding transformer on single-phase currents is investigated. Compliance of fuse tripping times with DIN VDE 0100-410 is investigated as a function of the grid interconnector’s rated power.