DC corona discharge of a metal filament particle within parallel-plate electrodes

For the prevention of a particle-initiated breakdown within gas-insulated switchgear, fundamental characteristics of particle motion were investigated. It was found that the particle motion depends not only on Coulombic force, but on the corona discharge from the tip of a particle, Thus, the corona current from a fixed particle on the lower electrode was measured, for either positive or negative corona case. The measured current showed different characteristics of current depending on the polarity. Corona onset voltage of negative corona is somewhat lower than positive, but the breakdown voltage of negative corona is much higher. Although the current characteristics follow the square lag the applicable region of this law for positive corona is very small. Positive corona depends on the tip configuration contrary to negative corona.