GNERC Chair: Preliminary findings indicate second grid failure stemmed from Imereti line fault cascading across system

“During today’s session, the Regulatory Commission commenced its investigation into the second systemic blackout within its remit. This involves assessing the existing technical infrastructure, identifying relevant faults, and subsequently formulating measures to prevent future system shutdowns,” stated Davit Narmania, Chairman of the Georgian Energy and Water Supply Regulatory Commission (GNERC).

According to Narmania, initial reports were received during today’s session from Georgian State Electrosystem and other stakeholders, though certain data remains under active review.

“Once all data has been collated, we will be in a position to draw definitive conclusions. Based on preliminary assessments, the trigger for the second systemic breakdown was a fault on the ‘Imereti’ high-voltage transmission line, which subsequently cascaded across the entire grid. Put simply, the system’s trip mechanisms failed to operate as intended. The root cause of this failure will naturally be established, following which appropriate preventive measures will be implemented.

Enguri HPP, as you are aware, is one of the most critical hydroelectric facilities capable of participating in frequency regulation and balancing various technical parameters, and it possesses its own protective systems. Preliminary information indicates that issues also arose within certain elements of these protective systems. Consequently, an overseas technical team—responsible for the original installation of this equipment—has been brought in to inspect the situation firsthand and provide us with their formal assessment,” Narmania stated.

He further noted that all relevant agencies and personnel are submitting their observations and data for analysis.

“Relying on this vast volume of information, we must render a verdict assessing a fault that unfolded in a matter of milliseconds, which is no easy task. These protection systems have functioned reliably in the past, yet on this occasion, they failed to deploy. Why this failure occurred is precisely the question we have raised, and we require clear answers. The conclusions of the specialists brought in specifically for this purpose will assist us in obtaining those answers.

Protective equipment is not exclusive to Georgian State Electrosystem; Enguri HPP and other generation assets also possess protective mechanisms, all of which must operate in complete synchrony. Therefore, we ought not to jump to premature conclusions. Enguri HPP has performed this stabilising function on countless occasions; whenever disturbances arose in the grid, Enguri absorbed the shock and balanced the system. That is precisely why Enguri serves as a regulating plant. Had we possessed a second facility equivalent to Enguri, it would have safeguarded us against this outcome in the event of a fault at Enguri; unfortunately, no such second facility exists,” Narmania added.