Georgia’s second nationwide power outage in late July was preliminarily caused by a fault on the high-voltage Imereti transmission line that subsequently affected the wider power system, according to the Georgian National Energy and Water Supply Regulatory Commission, or GNERC.
GNERC Chairman Davit Narmania presented the preliminary assessment on 4 August as the commission began examining the second systemic outage, which occurred on 25 July.
He stressed that the investigation remains under way and that final conclusions will be possible only after technical data and assessments from the organisations involved have been collected and analysed.
Protection mechanisms under examination
According to Narmania, the system’s disconnection mechanisms did not operate properly after the fault occurred. Investigators are now examining why the initial incident was able to spread across the electricity system instead of being isolated.
The inquiry will evaluate the operation of existing technical systems, identify possible deficiencies and propose preventive measures intended to reduce the risk of similar outages in the future.
Narmania said that preliminary information also indicated possible problems in certain parts of the protection system associated with Enguri HPP. A foreign technical team involved in the original installation of the relevant equipment has been invited to examine its operation and prepare an assessment.
Enguri HPP’s balancing role
Enguri HPP is one of Georgia’s principal regulating hydropower facilities and plays an important role in frequency control and the balancing of the national electricity system.
According to Narmania, protection systems are installed not only across the transmission network operated by Georgian State Electrosystem, but also at Enguri HPP and other generation facilities. These mechanisms must operate in coordination when disturbances occur within the system.
He noted that Enguri HPP had successfully supported the system during previous disturbances, but said the relevant protection mechanisms did not perform as expected during the July incident.
Narmania also argued that the availability of another major regulating facility with comparable balancing capabilities could provide additional protection if one facility or part of the system experiences a technical problem. He presented this as an observation rather than a final conclusion from the ongoing inquiry.
Two outages under separate review
Georgia experienced major electricity interruptions on both 24 and 25 July, affecting Tbilisi and regions across the country.
GNERC began investigating the first system-wide outage shortly after the 24 July event. The regulator’s working group presented its initial observations concerning that incident during a commission meeting on 30 July, while examination of the second outage began on 4 August.
The regulator said the review may normally take several weeks, depending on the quantity and complexity of the technical information that must be reconstructed and assessed.
For Georgia’s energy sector, the inquiry places renewed attention on the coordination of transmission infrastructure, generation assets, protection mechanisms and balancing capacity. These issues will also be relevant as the country connects additional renewable generation and manages increasingly varied electricity flows across the system.
Source note: Based on statements by GNERC Chairman Davit Narmania reported by Georgian Public Broadcaster, with background from GNERC investigation announcements and public reporting on the 24–25 July outages.