Investigation of Discharge and Audible Noise Behavior of OHLs for Separated AC Half-Waves

The transition to renewable energy sources requires upgrades and expansion of the existing power transmission grid, which consists mostly of overhead power lines. Audible noise emission during foul weather poses challenges to these activities with respect to legal requirements and public acceptance. It is therefore necessary to investigate how the audible noise is generated and why some conductors have higher noise emission than others. Many studies have already been carried out under AC and DC stress. However, when analyzing AC voltages, the audible noise components of the individual half-waves of the conductor cannot be separated from each other. For this reason, this work examines the half-waves separately in order to gain a better understanding of the discharge behavior and the resulting audible noise emission for new and aged conductors. The broadband and tonal noise component as well as the number, amplitude of discharges and total charge are analyzed. The results show that intensity of the discharges have a greater influence on the audible noise emission when comparing both half-waves separately, but the number of discharges and therefore the number of droplets on the conductor has the greatest impact on the broadband and the tonal component of the total audible noise emission. The reason for that is that the emission of the positive half-wave has a greater influence on the total audible noise emission than the negative one.