Streamer Propagation in OIls and its Relationship to Arrester Application

Using a high speed image converter camera together with a shadowgraphic technique, positive streamer velocities have been measured as a function of instantaneous voltage on impulses of varying shape and duration in transformer oil and Marcol 70. They have been found to propagate at a constant velocity which is independent of the instantaneous value of the voltage. The velocity appears to correlate with the rate of rise of voltage rather than the initation voltage itself. This result has implications for the use of arresters as protection for electrical equipment and these implications have been examined using breakdown measurements.