Streamer initiation in dielectric liquid using a semi-uniform electrode geometry

This paper presents an experimental study of streamer inception in mineral oil in point-plane and semi uniform-geometry. The latter is constituted of parallel planes with a thin metallic point of calibrated size attached on a plane electrode. A systematic study of streamer initiation has been carried out versus geometric parameters: gap distance and point size (tip radius and length). As compared with the point-plane gap, the initiation of streamers is impeded due to the presence of the metallic plane behind the point, that shields the electric field on the metallic tip. The extrapolation to the general case of a particle-initiated breakdown in liquids and the effects of particle size are discussed.