Positive streamer propagation and breakdown time lag in cyclohexane under micro-second rectangular pulse voltage

Electrical breakdown phenomena in cyclohexane for a point-to-plane gap configuration have been investigated using an image converter camera and a photooptical current measuring technique. Camera records for 4-mm gap spacing show that the sonic and supersonic propagating velocities of the positive streamer in the liquid are 1.3 km/s and 2.8 km/s, respectively. Time-to-breakdown for gap spacings of less than 1 mm was directly measured from prebreakdown current. Two linear relations to the time lag and gap spacing are obtained, which indicates two constant propagation velocities: 0.18 km/s (subsonic) and 1.3 km/s.<>