Microgrid Management with a High Share of Renewable Energy Sources

In order to validate the different functions of a low voltage microgrid, a specific test configuration has been set up in the Design Centre for Modular Systems Technology (“DeMoTec”) of the Institut für Solare Energieversorgungstechnik (ISET). In this highly innovative microgrid configuration, the grid control is distributed among three distant inverters which are not linked by any fast communication link. For primary control purposes, the sharing of power between these different grid-forming inverters is made possible using the selfsync algorithm. Several critical situations have been successfully tested, which included the transition from interconnected to island operation after a fault on the main grid or the transition from island to interconnected operation (Re-connection to mains after fault, microgrid black start). In all these situations, the microgrid has demonstrated that it is today possible to combine a reliable uninterruptible power supply with the integration of a high penetration level of renewable energy sources (wind and PV).