Reduction of audible noise using asymmetrical bundles for 1000 kV transmission lines: Full-scale test results of Akagi test line

Long-term tests of asymmetrical bundles which have the potential to suppress corona activity on conductor bundles have been carried out in the Akagi test line, and their corona performance, mainly audible noise, was measured. Asymmetrical bundles generally show good performance; however, the ''added system'', which is classified as an asymmetrical bundle due to the addition of a subconductor at the bottom of regular symmetrical conductor bundles, shows better performance. These reduction techniques can be applied to actual 1000 kV transmission lines because of their good corona-suppressing performance, if problems such as mechanical performance and unbalanced current passing through individual subconductors can be resolved.