Dielectric Response Characteristics and a Preliminary Ice-Type Discrimination Framework for Ice Accretion on High-Voltage Transmission Lines

Atmospheric ice accretion on transmission lines threatens the safe operation of power systems, whereas existing monitoring methods mainly focus on ice thickness, load, or morphology and provide limited material-related information for distinguishing ice types. This study investigates the dielectric response of ice and snow samples to evaluate its feasibility for preliminary ice-type discrimination. Artificial glaze ice and natural snow samples were measured using a self-built temperature-controlled parallel-plate system within 10–100 kHz. The effects of freezing-water conductivity, temperature, surface water film, and snow density were examined, and representative glaze ice, dry snow, and wet snow samples were further compared under the same measurement framework. The results show that the dielectric constant generally decreases with frequency, while conductivity, water film, and density mainly increase the response magnitude and, in some cases, alter the prominence of loss-related features. These trends are consistent with reported dielectric dispersion, conductive loss, and snow density-related mixing behavior. Dielectric loss provides clearer differences between glaze ice and snow-related samples than dielectric constant alone, whereas dry and wet snow require combined consideration of dielectric constant and loss. A preliminary two-step hierarchical framework is therefore proposed for the tested sample set. Further validation over broader frequency ranges and conductor-like geometries is required before practical application.