Comparative study on corona-generated audible noise and radio noise of ac long-term operating conductors with two bundle types

Abstract The corona-generated audible noise (AN) and radio noise (RN) of the long-term operating conductors with two bundle types was investigated and compared based on a corona cage measurement system. The surface morphologies of eight conductors were measured and the average surface roughness ( R a ) was calculated. With the raise of conductor bundles, the maximum electric field distortion level ( β 4 ), the relative difference of ionization intensity ( γ 4 ) between long-term operating conductors and new conductors decreased. Adding the number of sub-conductors turned out to be an effective method to improve AN and RN of long-term operating conductors in the contaminated areas.