363 / 2022-03-15 17:16:17

Paschen’s curve for porous dielectric discharge

paschen curve,gas discharge,porous media

Purpose/Aim

With distorted spatial structure, dense and random pores, porous dielectric is widely used for high voltage engineering. Its insulation property and thermal conductivity can be modified by internal plasma induced by high voltage discharge under low pressure. However, discharge mechanism of porous dielectric is not clear. In order to analyze the breakdown characteristics of porous dielectric, the Paschen’s curve of porous dielectric is measured.

Experimental/Modeling methods

The porous dielectric discharge platform was built inside the vacuum chamber. Porous medium is clamped with a pair of plate electrodes. Paschen’s curve of different gases in porous dielectric with different porosity were measured under DC voltage.

Results/discussion

Results showed that Paschen’s curves with porous dielectric tended to shift to a higher pd value and breakdown voltage was larger than that of discharge without porous dielectric. In addition, the larger heterogeneity of porous structure, the more significant the shifting of Paschen’s curve.

Conclusions

We infer that it is because the inhomogeneity of spatial structure causes the attenuation of reduced electric field in porous dielectric, which reduces collision ionization and inhibits the formation of electron avalanche. This study provides a new theoretical perspective for the interaction between plasma and porous dielectric materials in high voltage engineering.