Positive streamers in short and large gaps in hydrocarbons of various chemical natures

The objective of this study is to document the relationship existing between liquid composition and streamer propagation in large gaps. Measurements are carried out in a series of hydrocarbon liquids of various chemical natures (aliphatic, aromatic, polyaromatic), both in short point-plane gap (6 mm distance, 1 μm tip radius), and in larger gaps up to 20 cm. These measurements are based on fast imaging techniques (2D and streak photographs), coupled to transient current and light recording. A correlation is established between the threshold propagation voltage of filamentary streamers, the tendency to form branches, and the behaviour at very high voltage.