Electric fields and corona currents in needle-to-meshed plate gaps

This paper is aimed at evaluating the electric field, the corona onset voltage and the corona current in negatively stressed needle-to-meshed plate gaps as compared with the case of using a flat plate. The charge simulation method is used for calculating the electric field in the gap. The onset voltage is evaluated based on the calculated field and the criterion for self-recurring single electron-avalanches in the ionization-zone around the needle tip. The corona current - voltage characteristics were measured for thin and thick needles at two gap spacings with meshed and flat plates. The corona currents with meshed plates are lower than those with a flat plate; even the corona onset voltage with the flat plate is higher than that with the meshed plate.