On 05/30/2023 at 10:28:30 there was a remarkable frequency jump of +100mHz (m, not M ;)  ) within 10s  in the European ENTSO-E grid, see detail.png.   Within 1.5h things were back to normal, see full.png. Reportedly https://www.netzfrequenzmessung.de/aktuelles.htm#:~:text=Am%2030.05.2023%20um%2010,tempor%C3%A4r%20vom%20Verbundnetz%20abgekoppelt%20wurde. Ukraine was split from ENTSO-E grid. The missing 1.4GW load cranked up the frequency. Allegedly frequency in Ukraine settled at only 48.2Hz. There is no information about the time of resync. Before 2/24/22, the begin of the war, there where EU plans to disconnect UA from Russia and sync to ENTSO-E by 2023. These plans were speeded up and on 2/27/22 UA and Moldova asked for joining ENTSO-E, which took place on 3/16/22. So we had the bizarre situation that Europes' largest Nuclear Power Station Zaporizhia (5,7GW) produced energy for Europe under russian occupation. On 06/09/23 the last reactor was shut down. Cheers Detlef