Investigation of audible noise performance of HVAC conductor bundles at altitude of 2261 m

Abstract

Extra or ultra-high voltage transmission lines can exhibit strong corona discharge and generate severe audible noise (AN) at high altitude areas, which has become a critical limiting factor for power lines construction. However, the AN data of bundle conductors at high altitude are very rare, which cannot support the power utilities adequately to make reasonable conductor selection. In this paper, sound pressure level (SPL) of 14 types of bundle conductors were investigated by using an ultra-high-voltage (UHV) corona cage (8 m × 8 m × 35 m) at altitude of 2216 m, where the bundle number between 4 and 12 and the conductor types may be used in 500 kV, 750 kV or 1000 kV power transmission project. Then many valuable AN data were obtained; the influence of bundle number and subconductor diameter on acoustic power density level (PWL) were analyzed; and an A-weighted PWL calculation method was proposed. Besides, by comparing the AN data obtained from the low-altitude area (altitude: 23 m), the AN altitude correction factor was concluded, and the influences of conductor parameters and the surface electric field strength on correction factors were discussed. The results obtained in this paper can provide important data for the construction of high-altitude alternating current (AC) power lines.