Electrical and Thermal Conductivities of High Temperature Air Contaminated by Ablation Gas of PTFE

Abstract

The high pressure arc discharge which is produced in power circuit breakers or at fault point in electric power system is usually contaminated by electrode metal vapor or ablation gas of polymeric materials. The transport and thermodynamic properties of such contaminated gas medium is of much importance for a quantitative analysis on the electrical characteristics of the arc, and its interruption process.
In this paper, the electrical and thermal conductivities are calculated for high temperature air contaminated by ablation gas of PTFE material. The PTFE is widely used as nozzle material of circuit breaker or narrow gap of primary cutout. The calculation are carried out under the assumption of thermal equilibrium, in the temperature range from 2, 500 to 30, 000 K, the pressure range from 0.1 to 3.0 MPa and for mass contamination ratio of the PTFE gas from 0 to 100%.
The thermodynamic data obtained supply basic information for analyzing the arc inter-ruption process contaminated by the PTFE gas.