Experimental Support for a Model of Positive Streamer Propagation in Liquid Insulation

Results are presented of experiments to determine positive streamer velocities in aliphatic hydrocarbons. For the millimeter gaps employed it-is found that the streamer tip velocity goes through a minimum with growth across the gap. A simple model of streamer growth also predicts a velocity minimum. The position of the minimum is used to derive a tip charge value for the observed streamer. Effective radius is a disposable constant in the model. Stored charge values, following streamer growth can be used to approximately fix this effective radius. The observed effects of varying the gap length or of adding lowionization impurities to the liquids are shown to be consistent with the model proposed.