The leader propagation velocity in long air gaps

• Experimental measurements of long gap discharges and its interpretation are the base of engineering equations and complex models to design clearance distances, lightning protection systems, among others. Parameters like leader propagation velocity, average electric field of the leader channel, stability electric field of the streamer region, etc. are derived from experimental measurements for rod-plane arrangements. However, in high voltage engineering geometries are not only rod-plane arrangements but also rounded electrode geometries. Experimental measurements of sphere - plane arrangements are presented in this paper. Attention is given to the velocity of propagation of the leader. The velocity of propagation of the leader is compared for two different applied voltage conditions, such as overvoltage and non-overvoltage. Experimental observations indicate that the velocity of the leader does not have a linear relationship with the increment of the applied voltage, as described by other authors for rod-plane arrangements. By means of a model based on the physics of the discharge, it is observed that the velocity of propagation of the leader depends on the injected charge to the leader channel. The injected charge depends on the background electric field, the potential at the leader tip, the steepness of the applied voltage waveform, among other parameters.

Ämnesord

NATURVETENSKAP  -- Geovetenskap och miljövetenskap -- Meteorologi och atmosfärforskning (hsv//swe)

NATURAL SCIENCES  -- Earth and Related Environmental Sciences -- Meteorology and Atmospheric Sciences (hsv//eng)

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