Georgia’s Energy and Water Supply Regulatory Commission (GNERC) has presented preliminary findings from its investigation into the large-scale power outage of July 25, 2026.
According to the investigation team, the initial cause of the system collapse was the shutdown of the 500kV “Imereti” transmission line. After Georgia’s power system disconnected from Azerbaijan’s grid, sharp frequency and voltage fluctuations led to cascading outages of power plants and consumers, resulting in a nationwide blackout.
GNERC said the line’s protection system did not operate correctly and with the required speed. While the protection system should have disconnected the damaged section almost instantly, the line was switched off from the “Zestafoni 500” substation side in 104 milliseconds, while from the “Engurhesi” substation side it took 797 milliseconds.
The regulator said the delay exceeded the 400-millisecond threshold required to trigger automatic separation from Azerbaijan’s system. GNERC is continuing to investigate the reasons behind the protection failure and how power plants operated after the system entered an isolated mode. A final report will be issued after additional documentation is reviewed.
