Electricity Transmission Line Kavkasioni was shut off with the activation of relay security system from both sides at 5am, December 24, 2017. Special equipment defined the location of the emergency shut off in 104 km distance from Engurhesi, on the territory of Russian Federation, on northern slope of Nakhari pass. Due to heavy snow and difficult relief, the territory was inspected by helicopter. The damaged location was found in the span between N 13 and N14 towers.
It was managed to visit the site and define the scales of the damage on December 31, 2017. As a result of the inspection, it turned out that the air wave come from the avalanche disconnected the conductors of B and C phases, other conductors were also damaged there. Disconnected conductors were covered with frozen snow and ground and it was impossible to examine them by that moment.
Besides, due to the existing threat of avalanche it was unsafe to conduct rehabilitation process there. Considering the mentioned a decision was made about restoration of functioning of Kavkasioni under the temporal scheme; the cut off conductors were disconnected and other damaged ones were repaired. Because of it the loading of the electricity transmission line was limited to 400MW.
The restoration of the work on the northern slope of Nakhari pass became possible only in May. By that moment there was no threat of avalanche and the snow was fully melted. After the inspection it was found out that the conductors were disconnected in the connective clicks.
The representatives of Karachaevo branch office of Sakrusenergo JSC and ПАО ФСК МЭС «Юга» examined the state of the conductors on the site and made decision about the complete replace of the conductors in the whole three phases.
Kavkasioni (500kV) was put under repair on May 19, 2018. The contractor company AlphaStroy Ltd in cooperation with the Karachaevo branch office of Sakrusenergo JSC is implementing the rehabilitation work. As a result of it, the aluminum-steel conductor (АС 300/204) of 6 km length will be replaced in the span between the N 13 – N 14 towers of the electricity transmission line Kavkasioni (500 kV).