On 15 January 2021 at 17:34 Moscow time, the 220 kV Atyrau-Kulsary overhead line (L-2025) was shut down under abnormal weather conditions in the Atyrau region, and a part of Atyrau and Mangystau oblasts were disconnected from the Unified Power System. At the same time Karabatan GTPP shut down a total of 242 MW generation units, which resulted in a sharp drop in frequency.
The emergency frequency control automatics disconnected 150 MW of consumer load (60 MW in Atyrau oblast and 90 MW in Mangystau oblast). At 18:07, a 200 MW unit at the MAEC TPP No.3 was engaged.
The restoration of normal power supplied was impeded by severe corona discharging at high-voltage switchgear equipment in Atyrau oblast.
Now, all restrictions in Atyrau and Mangystau oblasts have been lifted. Electricity supply to consumers has been fully restored.