The icing disaster of transmission line poses a serious threat to the safe operation of power systems. Currently, a variety of anti-icing and de-icing methods have been developed, but each method has its limitations. Particularly, serious icing areas with micro-climate and micro-topography characteristics lack effective solutions. This paper takes into account the characteristics of expanded conductors and the limitations of bundle conductor transmission lines. By considering wave impedance, natural power, and accounting for the skin effect of current, the split conductor is equivalently transformed into a single conductor, and the equivalent single expanded conductor is obtained. Subsequently, the surface electric field characteristics of the split conductor and its equivalent single expanded conductor in icing area are analyzed and compared. The findings reveal that when the total conductor cross-sectional area of the conductor cross-section before and after the equivalent remains the same and the wave impedance is equal, the expanded conductor, compared to the bundle conductor, not only significantly reduces the number of sub-conductors and the icing load on the transmission line, but also the maximum electric field intensity on the surface of the expanded conductor is lower than that of the bundle conductor when the radius of the expanded wire is equal to the equivalent single wire radius of the bundle conductors. Therefore, in severely icing areas, the expanded wire with an equivalent radius to that of the bundle conductors exhibits excellent surface electric field characteristics, significantly reducing ice wind load and improving anti-icing capacity.