Lab and field test results of a power-flow controller for coupling of low-voltage grids

Abstract:
The increase of renewable energy sources (RES), particularly in rural areas, leads to a sharp increase of peak loadings in low-voltage (LV) grids. This can result in voltage violations and thermal overloads making significant investments necessary. One option for a cost-efficient solution can be the coupling of LV grids, i.e. the meshing of two adjacent LV grids. Thereby, voltage stability can be improved and synergy effects can be used in terms of balancing load and generation. However, undesirable power flows (PF) may occur as a result of the coupling. A controller that regulates these undesirable PF at the coupling position is developed in the research project "FLOWKONtrol" funded by the German Federal Government. The controller has been tested in a lab environment and in a real grid. The performance results are presented in this paper.