Reduction of Audible Noise by Super-water-repellent Treatment of Transmission Line Surfaces

Evaluation of audible noise from surface processing conductors for AC overhead transmission line

“…The relationship between the "wetting property" [5,6] and the audible noise generated from a conductor when it is raining follows a trend in which the noise is softer as the conductor becomes more hydrophilic, and when extremely hydrophilic, the corona noise is greatly reduced. This is thought to be because as the hydrophilia of the conductor rises, water's separability (drain capability) increases, and the number of water drops attached to the surface of the conductor decreases.…”

“…This is thought to be because as the hydrophilia of the conductor rises, water's separability (drain capability) increases, and the number of water drops attached to the surface of the conductor decreases. However, it has also been shown that corona discharges are extremely small in conductors with highly hydrophobic surfaces, in direct opposition to the characteristics described above, and controlling the wetting property by using improved surface features in the conductors is known to be effective as a method to reduce audible noise [5,6]. Thus, the authors clarify the relationship between the wetting property of the surface of a conductor and the amount of audible noise generated, and then explore a surface processing method effective as a measure to reduce audible noise.…”