Discharges in liquids in point-plane gap under ac and impulse stress

Streamer inception and propagation has been investigated for cyclohexane in a 30 mm point-plane gap both for impulse and ac-stress. For impulse and ac conditions the negative streamers always have a lower inception voltage than the positive ones. Under ac the inception occurrence rate of streamers increases exponentially with voltage. At low rates space charge effects seem to be insignificant, while at increased voltages effects probably due to space charges can be seen. Due to the long duration of discharges, attention has to be paid to the time constants of the discharge measuring equipment to assure proper integration