Due to the different conductor fabrication technologies

test conditions

and climate environment

the empirical formula recommended by Bonneville power administration（BPA） is imprecise when it is used in predicting the audible noise（AN） level of utral-high voltage alternate current（UHVAC） transmission lines in China. Therefore

the audible noise values of seventeen types of bundle conductors whose division numbers are 6

8

9

10 or 12 are measured by using the corona cage

and the calculation method of acoustic power is derived by using a multiple linear regression method. Then

the audible noise levels of two long-term stations（Jiaozuo

Henan Province; Zhongxiang

Hubei Province）

as the 1 000 k V demonstration projects

were calculated by using the BPA formula and the formula presented in this paper. It is shown that the deviation between calculated value by the proposed formula and long-term testing L50 value is 0.66 d B in Henan station

and it is 0.32 d B in Hubei station. Besides

the corresponding deviation by BPA formula is 3.07 d B and 2.14 d B. Therefore

it is demonstrated that the proposed formula is more precise than BPA formula in predicting the AN levels of UHVAC transmission lines. The research results can provide a technical reference for the AN prediction of the UHVAC transmission lines in China.