Attacks on the Dnieper, Dniester and Kremenchug hydroelectric power stations

The disabling of the hydropower stations is important for two reasons:
-- No easily dispatchable power to compensate for loss of other producers (this may have been irrelevant now though).
-- The lost ability to correct and maintain the 50 Hz mains frequency on a very short term. Now on increasing load conditions, in case the frequency falls below about 49.5 Hz, the grid will just collapse. The transformers will pass less and less power through them as the frequency declines, further aggravating the situation. Also in some circumstances, the mains voltage may rise as the frequency drops. See: https://www.fingrid.fi/en/grid/power-transmission/maintenance-of-power-balance/#frequency-measurement-data

"The Russians launched rocket attacks on the Dnieper, Dniester and Kremenchug hydroelectric power stations, - the specialized publication Elektrovesti."