Improved analytical method for computing unipolar DC corona losses

The method does not rely on the constancy of the conductor surface field assumption, because a simple and realistic function that relates this field to the applied voltage level is incorporated into the analysis. The theoretical expressions are derived and applied initially to the coaxial cylindrical geometry and show satisfactory agreement with accurate measured data published by others. Using the bipolar co-ordinate system, modified formulas are then derived for the case of a cylinder above the ground plane. A function, that is dependent on both the line dimensions and the corona intensity level, appears in these formulas. The correlation between this function and the empirical constants of the Popkov´s formula is discussed. The accuracy of developed current/voltage characteristic is demonstrated for the case of a smooth cylinder above ground plane using various geometries and intensities of corona. Modified expressions are also suggested for the case of a stranded conductor above ground. The calculated results, using the present procedures, for different geometries and voltage levels, are in better agreement with experimental data compared with other referenced formulas.<>