Evaluation of Audible Noise from Surface Processing Conductors for AC Overhead Transmission Line

Abstract

Corona discharge may cause audible noise, and it is frequently generated from wet conductors of high-voltage AC overhead transmission lines. Audible noise arises more easily from new conductors that have lubricating oil on their surface than from aged conductors. In this paper, the corona characteristics, particularly audible noise, of conductors having various wetting properties is presented developing a corona-free conductor for AC overhead transmission lines. It was found that a conductor having a super-hydrophobic surface exhibited a minimized audible noise level, but it does not have sufficient durability for practical application. Furthermore, a conductor having a super-hydrophilic surface made by thermal spraying of TiO₂ showed good performance regarding the suppression of audible noise. The thermal spraying of TiO₂ seems to be an effective processing technique that has sufficient durability for practical application.