360 / 2022-03-15 17:20:31

On the estimation of electric field in positive leader channel considering non-local thermodynamic equilibrium effects

electrical field,positive leader channel,non-local thermodynamic equilibrium

Purpose/Aim

The measure of the electric field of the positive leader channel has always been a difficulty in high-voltage engineering. The method of indirect estimation cannot take into account the effects of physical quantities such as channel current and radius. Scholars obtain the leader channel electric field by establishing simulation models. Existing engineering models have defects in the assumption of local thermodynamic equilibrium(LTE). While non-LTE models are too complex for engineering applications. Therefore, a model of the electric field of the positive leader channel is proposed considering non-LTE effects.

Experimental/Modeling methods

The governing equations solved by COMSOL include charged particle conservation equation, energy conservation equation, and Ohm's law.

Results/discussion

When the gas temperature is in the range of 2000~6500K, the relationship between the reduced electric field of the pilot channel and the gas temperature can be approximated by piecewise linear approximation. In the range of 2000~3500K, it is similar to Gallimberti's conclusion that the reduced electric field is constant. However, when the gas temperature is in the range of 3500~4700K, the reduced electric field of the leader channel is obviously not constant.



Conclusions

The quantitative relationship between the reduced electric field of the positive leader channel and the gas temperature is established. Addressing deficiencies in the classic model that the reduced electric field is assumed to be constant and the non-LTE effects are not considered.