This report summarizes the measures implemented by all Continental European Transmission System Operators (TSOs) to prevent, detect and resolve Long Lasting Frequency Deviations (LLFDs), which occur exceptionally in the Continental Europe (CE) power system and which can contribute to larger frequency deviations such as that observed in the system on 10 January 2019.

ENTSO-E is convinced that the implementation of these measures will reduce the LLFDs in both size and number of occurrences, therefore reducing the risk to grid security due to large frequency deviations where LLFDs are a contributing factor.