Effect of Two Phase Mixtures on the Selection of the Discharge Path

This paper investigates the development, the breakdown process, and the discharge path selection of the lightning discharges while there exist two phase mixtures. 13 kinds of solid-gas mixtures and 3 kinds of liquid-gas mixtures are employed to study effect of two-phase mixtures (TPM) on the selection of the discharge path under lightning impulses. Grain size effects are shown upon these experimental results. When the diameter of solid or liquid grain is less than about 10 mum, the discharge path selects not TPM but air. And the discharge path selects TPM when the diameter is greater than about 100 mum. And the diameter is between about 10 mum and 100 mum, the discharge path selects TPM under negative lightning impulses, but it has a greater selection of air than TPM under positive lightning impulses. Volume fraction and permittivity of solid/liquid can also influence the selection of the discharge path.