Breakdown in CO2 and CO2/C2F4 Mixtures at Elevated Temperatures in the Range 1000-4000 K

Abstract

CO₂ is a promising gas for replacement of SF₆ in high voltage circuit breakers. The electric breakdown in CO₂ and mixtures with C₂F4 from PTFE nozzles is, however, still not fully understood. To understand the electric breakdown in CO₂ and mixtures with C₂F₄ from PTFE nozzles fundamental parameters like the temperature and pressure dependence of critical electric fields are needed. Data on critical fields is usually available based on simulations only and experimental validation is lacking so far. Our present contribution aims to close this gap and presents experiments where the breakdown fields in uniform and weakly non-uniform electric fields are determined at various temperatures and pressures. The gas temperatures were estimated from measurements with pyrometers. The results are compared to theoretical predictions.