Objective To analyze the critical meteorological conditions for conductor icing and melting, accurately predict the start and end times of conductor icing, and provide a basis for power departments to prevent icing disasters.

Method This study used the complete conductor icing records of eight winters from an icing observation station in Southwest China, and the simultaneous meteorological observation data from adjacent surface meteorological stations. Fisher discriminant analysis theory was applied to study the frequency distribution characteristics of meteorological factors of temperature, wind speed, relative humidity, water vapor transport, cloud cover at the start and melting moments of conductor icing.

Result The results show that conductor icing is most likely to occur when the temperature ranges from −3 to 0 ℃, the water vapor transport rate is 15～30 (g·m²·s⁻¹), and the relative humidity is ≥90%. During the melting stage of conductor icing, the temperature increases significantly and the wind speed strengthens. Based on the characteristics of meteorological factors in different stages. Fisher discriminant functions for icing occurrence and melting are established respectively. The effect test shows that the fitting accuracy of the discriminant equation for the icing start moment is 77.3%, and that for the icing melting moment is 68.99%, indicating the equations can reflect the actual icing situation.

Conclusion This method can provide ideas for line icing prediction, help improve the technical level of line design for icing, innovate and enrich the icing data analysis technology, and provide support for scientifically solving the problem of line design for icing.