The altitude correction term of the corona loss on alternating-current transmission lines

Abstract

The increase in mobility of charged particles causes high-voltage alternating-current (AC) transmission lines in high-altitude areas to be more likely to undergo severe corona discharge and associated losses, to the detriment of the economic efficiency of power transmission. Evaluating the corona loss on transmission-line conductors in high-altitude areas is conducive to conductor selection, parameter optimization, transmission-line tower arrangement, and optimization of the phase sequence arrangement. The altitude correction factor K of 3.33 dB/km recommended by the Bonneville Power Administration (BPA) in the United States is commonly used in engineering design, however, measured data indicate that the correction method may be subject to significant error, so the altitude correction factor is discussed under different weather conditions. K is suggested to be 4.5 and 1.5 dB/km separately under dry and rainy conditions, the better to evaluate the coronal loss.