On 10 January 2021, at 19:25 Moscow time, under abnormal weather conditions, with significant weather deterioration in the form of intensive ice formation, rain, and snow, 220 kV Inder-Atyrau high voltage power line was disconnected, and Atyrau and Mangystau oblasts switched to island operation.

At the same time two generator units at Karabatan GTPP with a combined load of 100 MW were shut down, which led to a sharp reduction in frequency in the islanded Atyrau and Mangystau oblasts. This in turn triggered frequency control emergency automation (disconnecting 95 MW of consumer load including 70 MW in Atyrau oblast, 25 in Mangystau oblast).

The emergency automation operation prevented even deeper frequency drop and potential blackout of these to oblasts.

At 23:22, one generator unit at Karabatan GTPP was put back into operation, increasing generation by 50 MW. At 22:59, a 200 MW unit at MAEC TPP-3 was engaged.

KEGOC personnel are currently working to eliminate the technological disruption.

The elimination and prevention of further escalation of technological disturbance is impeded by the strong corona discharges of high voltage equipment due to icing, snow and high humidity, which extremely dangerous for the personnel on duty involved in the switching operations. Therefore, additional safety measures were taken to reduce the risk of injury to KEGOC personnel.