The Effect of Ageing on Corona Discharge induced Audible Noise of Overhead Line Conductors

For HVAC overhead power lines, the audible noise emission due to corona discharges of naturally aged conductors during rain is much lower than that of new ones. Unexpected high noise levels after installing new conductors can cause annoyance and poses a challenge to social compliance and acceptance of overhead lines. In this contribution, we describe the phenomenon quantitatively, reveal the mechanisms that lead to excessively high noise levels and propose countermeasures. Audible noise data for conductors of various age (new and ex-service) is presented. Surface-chemical analysis is applied to various conductors, revealing the role of chemical conversion and the removal of contaminants such as lubricants. It is shown that the chemical reactions are likely to be mainly driven by corona…