De-icing/anti-icing techniques for power lines : current methods and future direction

A review of de-icing and anti-icing methods developed during the last decade was presented. Among the 37 methods inventoried, 11 were preventive, 13 were for de-icing, and 13 were for mitigation. Constraints of applicability for de-icing and anti-icing methods included specific electrical, mechanical and thermal constraints relative to power line operation as well as environmental constraints such as UV radiation. Methods under consideration for future use by Hydro-Quebec were the heating of ice-covered line conductors by electrical current and a new load shifting technique. Details of an inventory of circuits, conductor load capacities and seasonal load variations of the Hydro-Quebec transmission network were presented, in which 120 circuits were identified as potential candidates for load transfer de-icing. Developments in reduced voltage short circuit methods of heating were discussed as a preventive measure against the slow build-up of ice on conductors. High-voltage circuit methods and testing with twin and quad bundles were outlined. Issues concerning ground wire de-icing, and Joule effect de-icing were discussed. Passive icephobic coatings using ultrathin film depositions based on self-assembled monolayers and diamond-like carbon were reviewed. Active ice shedding methods using an ice shedding device to transmit vibrations to cables were outlined, as well as a device to slowly twist the wire or the conductor around its longitudinal axis. It was noted that only 19 per cent of all the inventoried methods were efficient and currently in use. It was concluded that further research is needed to develop a greater understanding of ice adhesion phenomena. 45 refs., 8 figs.