Numerical calculation of the corona onset voltage for bundle conductors for HVDC transmission line

The corona onset voltage (COV) for bare overhead bundle conductors for transmission lines has been investigated using numerical calculations and the gas discharge theory. First, an accurate numerical method, the charge simulation method, was used to calculate the electric field distribution in the vicinity of bare sub-conductors in bundles. Then the electric field values and a criterion from the gas discharge theory were used to evaluate the onset voltage for negative coronas on the bare sub-conductors. The COVs obtained are in good agreement with literature data for laboratory models and full-scale test lines. Some numerical results for the COV for six-bundle conductors are also discussed.