Modeling Wet-Snow Shedding from Current-Carrying Conductors

The initiation of wet-snow shedding from currentcarrying conductors was studied experimentally and theoretically. A suspended cable with cylindrical snow accretion was considered, and some of the snow properties at the end of sleeve were measured and calculated until snow shedding. The current in the cable appears to be a heat source which accelerates snow melting, similarly to air temperatures above freezing, wind and heat radiation. All of these effects were taken into account to study how they contribute to the snow-shedding process. The properties observed were the liquid water content, density, and profile of snow at the end of a snow sleeve. As the snow warms, if the liquid water content and density increase to high enough levels, adhesion to the cable is weakened so that the end of the snow sleeve turns downward and then falls off. The experimental procedure involved forming a wet-snow sleeve on a suspended cable with negligible sag, frequently measuring snow properties of interest under controlled ambient conditions, and observing the deformation of the snow-sleeve until shedding occurred. The theoretical model applies the heat balance of the snow sleeve to calculate the effects of the heat sources mentioned, and simulates water percolation in the cross-section at the end of the snow sleeve from the top half downward. The model provides the rate of increase of liquid water content and density of snow in the end section, and predicts the deflection of the same section together with the time when this section is detached from the cable and snow sheds. The theoretical results were compared to the experimental observations, and satisfactory coincidence was observed in most of the cases examined.