Emergency Island Mode for Distribution Grids.

Driven by the energy transition towards renewable generation, more and more storage systems will be installed into distribution grids for grid balancing tasks like frequency or ramp rate control, energy delivery on schedule etc. Those units are operated in grid following mode (GFL) to fulfill present grid standards. In the meantime, many rural communities provide their landscape for renewable energy installations with negligible monetary profit in many cases. During bad weather conditions (thunderstorm, heavy rain, or snowfall) such communities often suffer from local blackouts due to interrupted main power lines, even if enough local renewable energy generation potential would be available at the same time. Operating the discussed grid connected storages in grid forming mode (GFM), provides the chance to keep power up, even in case the main power line is disconnected. In Bordesholm (Germany) such a system has been commissioned in 2019. The system design and operational results are described in this paper. [ABSTRACT FROM AUTHOR]