Corona emission and ozone production by carbonized and oxidized high-voltage wires

High-voltage wires exhibit corona discharges that cause emission of ozone. Precipitation, dirt, and wire imperfections have been shown in earlier works to increase both processes by a factor of up to 50. Here, a small coaxial cylinder setup is used to quantify the effects of volatile organic atmospheres and wire oxidation on corona and ozone production. With both positive and negative dc, corona initiation voltages can be lowered by a factor of about 4 in the presence of flake-forming chemistry, accompanied by very large increases of corona current. These results all fit the simple Cobine and Townsend model, which permits extrapolation of our corona current measurements to different wire conditions. Ozone generation rates were measured with ozone test papers in a sealed setup. Approximately 25 ozone molecules per corona electron were obtained from a negative oxidized copper wire at 24 kV.