A new method to calculate corona losses for active conductors considering real transmission line unbalance

This paper shows the characteristics of an algorithm that calculates the corona losses of transmission lines. The line can have up to four circuits, with any configuration, with single or bundled conductors, and taking into account the line unbalance. This is achieved by modelling the lines in phase quantities, for active conductor, and calculating the corona losses for each one. The results are given per active conductor and average per bundle. In lines with several conductors per phase the results are given per circuit and a total one. These characteristics allow choosing the most convenient configuration and spacing for the conductor bundles, which will reduce and balance corona losses. The results found with this method show that the value of the losses calculated with the formulas with transmission lines symmetrically transposed is conservative. The configuration and the number of conductors per phase have a noted influence in the value and the asymmetry of the corona losses. In double circuit lines, corona losses can be reduced by changing the arrangement of the phases of circuit two in reference to circuit one, with the advantage that, at the design stage, those changes are costless.