Federal Grid of Unified Energy System : Rosseti FGC UES cranks up ice-melting in Southern Russia 4.5-fold last winter

Rosseti FGC UES cranks up ice-melting in Southern Russia 4.5-fold last winter

05/13/2021

Rosseti FGC UES has made 142 ice melts on the conductors and earth wires of backbone 220-500 kV transmission lines in the south of the country. The maximum ice load in the autumn and winter period was as much as 1600 kg per span. The timely ice melting eliminated the risk of conductor breakage under the ice load and ensured stable delivery of power to over 26 mn residents in the Southern and North-Caucasian federal districts.

December of 2020 was the hardest month with 78 ice melts. The ice-combatting season ended in late April.

Most of all, the ice was melted on the lines in the North Caucasus: 330 kV Zaramag HPP-1 - Vladikavkaz-2 and Zaramag HPP-1 - Nalchik (27 times), Chirkey HPP - Chiryurt (13 times), Ilyenko - Baksan (11 times). Those lines go across mountain passes at altitudes around 1,000 meters above sea level and are most susceptible to icing in winter time.

High humidity, winds, sharp temperature fluctuations typical for the Southern Russia's climate in cold season all contribute to the icing of the transmission line conductors. the icing is dealt with using ice-melting systems. For that purpose, special transformers and rectifiers are plugged in at substations, which are able to create high currents in the power transmission line circuit. The high currents heat up the conductors and earth wires, forcing the ice to thaw. The ice load monitoring system allows keeping a close eye in real time on the formation of ice on the conductors. Using the conductor weight, air temperature and wind strength measurements, the system shows a detailed pattern of adverse weather effects on the status of the lines.