A special commission of the Energia Coordination Dispatch Centre (CDC Energia), which included representatives of the system operators of the energy systems of Central Asia, in particular Kazakhstan, Uzbekistan, and Kyrgyzstan, completed the investigation of the accident that occurred on 25 January 2022.
       The Commission established that the accident was caused by outages in the power system of Uzbekistan. On that day at 11:59 a.m. Nur-Sultan time, a short circuit occurred on the line disconnector of the 500kV high voltage overhead line connecting Syrdarya thermal power plant (TPP) and 500kV Tashkent substation (Uzbekistan). The subsequent unwanted tripping by the differential protection of 500kV bus systems I and II caused a significant reduction in generation at Syrdarya TPP, multiple blackouts in the adjacent power grid and 2,100 MW surge in 500kV North-East-South electricity transmission system of the Unified Power System (UPS) of Kazakhstan (7 times higher than permitted).
       The emergency automatics of KEGOC power grids and power plants in the south of Kazakhstan operated without fail and isolated the power system in case of system emergencies. Thus, it prevented a blackout of consumers in the southern zone of Kazakhstan, while maintaining electricity supply to approximately 60% of consumers in the south of the country. At the same time, the power systems of Uzbekistan and Kyrgyzstan were completely de-energised.
       It took four hours to rectify the emergency and re-energise all consumers in Kazakhstan, which demonstrates the high professionalism of the personnel of the system operator of UPS of Kazakhstan. In Kyrgyzstan, the power supply was restored more than a day later, and in Uzbekistan, the same took four days.