Application of a corona onset criterion to calculation of corona onset voltage of stranded conductors

The conditions under which corona first occurs for any set of electrodes are an important design consideration since corona can limit the performance of any given configuration of electrical conductors. Here, the 60 Hz ac corona onset voltage for a stranded wire in air is calculated. The criterion involves the characteristics, i.e. composition and pressure, of the gas in which the conductor is immersed and the electric field in the vicinity of the conductor surface. It is found that the calculated corona onset voltage agrees reasonably well with experimental data and that its behavior as a function of overall conductor radius and number of strands is as expected.