Investigation of supercooled water droplet sticking efficiency during power transmission line icing using digital holography

Abstract. Transmission line icing severely threatens the safety of the power grid. Accurate prediction of the sticking efficiency (the proportion of supercooled droplets that remain on the conductor after impact, excluding bouncing and splashing) is critical for preventing and mitigating icing disasters. Traditional prediction models for sticking efficiency typically exhibit significant errors under complex conditions (e.g. varying wind speeds and precipitation intensities), thereby limiting their practical applications. To overcome this drawback, a multi-stage coupled model based on coaxial digital holography was proposed, in which supercooled droplet diameters, velocities, and collision angles were precisely measured. These measurements were integrated into a multi-stage framework that couples droplet impact dynamics and thermodynamics to compute the sticking efficiency, thereby overcoming the accuracy limitations of existing models in complex environments. Experimental results show that the new model’s prediction errors remain below 3.5 % across a range of conditions, which is a significant improvement over traditional models, underscoring its enormous potential in engineering applications.