A 2D numerical study on collision coefficient of single conductor under direct current electric field

Abstract In early spring or winter, supercooled raindrops impact on transmission lines and accumulate ice on its surface frequently, which may induce galloping vibration occurs. Studies on collision coefficient or icing mostly focus on key parameters of wind velocities, raindrop sizes and conductor diameters, whereas few involve electric field. In order to clarify the influence of the direct current electric field on the collision coefficient of transmission lines, a calculation formula of the mass flow rate of raindrops was proposed, and the process of raindrops hitting the conductor surface is numerically calculated by the Euler–Lagrange method. The effects of electric field intensity, conductor diameter, cross‐sectional shape, wind velocity, raindrop diameter and charge density on the collision coefficient of transmission lines are analyzed. The results show that the collision coefficient decreases with the increase of electric intensity. As the electric intensity increases from 0  to 66.7 kV/cm, the collision coefficient decreases about 33%. Because of the repulsion between the conductor and raindrops, more raindrops move away from the conductor surface and collision coefficient decreases. The collision coefficient of the actual conductor under no electric field is slightly smaller than that of the simplified circular cross‐section. Under DC electric field, the collision coefficient of the conductor decreases with wind velocity increase up to 8 m/s. Beyond that threshold, the collision coefficient is almost constant.