On the initiation of negative streamers at mineral oil-solid interfaces

This paper reports the probability distribution of negative streamers initiated in mineral oil with and without a solid interface. In addition, the charge injected by conduction currents prior to the streamer inception is presented. Impregnated paper and polymeric films made of PET, PTFE and PVDF are tested as solid materials. Comparison of the conduction charge for the different oil-solid interfaces is presented. It is found that the permittivity of the material used at the solid interface does not influence significantly the condition for streamer initiation in mineral oil. A nonlinear increasing of the charge readings for the impregnated paper, PET and PVDF cases are observed.