Breakdown Electric Field of Hot 30% CF₃I/CO₂Mixtures at Temperature of 300–3500 K During Arc Extinction Process

Abstract

We calculated the uniform dielectric breakdown field strength of residual 30% CF3I/CO2 gas mixtures during the arc extinction process over the temperature range 300-3500 K at 0.1 MPa. The limiting reduced field strengths are decided by a balance of electron generation and loss based on chemical reactions estimated by the electron energy distribution function (EEDF), which employs the Boltzmann equation method with two-term expanding approximation in the steady-state Townsend (SST) condition. During the insulation recovery phase, the hot CF3I/CO2 gas mixtures have maximum dielectric strength at a temperature of about 1500 K. At room temperature 300 K, the electric strength after arc extinction (90.3 Td, 1 Td=10 −21 V·m 2 ) is only 38% of the original value before arc (234.9 Td). The adverse insulation recovery ability of CF3I/CO2 gas mixtures in arc extinction hinders its application in electric circuit breakers and other switchgears as an arc quenching and insulating medium.

Equivalence between C5F10O Addition and PTFE Vapor Contamination in the Particle Composition and Critical Electric Field Strength of High‐Temperature CO2/O2 Gas Mixture

“…Alternative arc‐extinguishing gases for gas circuit breakers are roughly categorized into two types, natural gases such as CO 2 , N 2 , O 2 , and so on, and artificial gases such as C 5 F 10 O, CF 3 I, C 4 F 7 N, and so on. As specifically proposed examples, CO 2 and its combinations, such as CO 2 /O 2 , CO 2 /C 5 F 10 O, CO 2 /CF 3 I, CO 2 /O 2 /C 4 F 7 N, and CO 2 /O 2 /C 5 F 10 O, have been researched [2–16]. Here, the artificial gases should be mixed with natural gases, and not be used alone, because of their high liquefying temperature.…”

Breakdown characteristics of CF3I/N2/CO2 mixture in power frequency and lightning impulse voltages

“…The partial discharge inception voltage of CF 3 I/CO 2 was measured in needle-plate electrodes and the result indicated that CF 3 I/CO 2 with the mixing ratio of 20%-30% was able to replace SF 6 as an insulation medium [17]. The dielectric breakdown field strength of CF 3 I/CO 2 during the arc extinction process was calculated and the result showed that the insulation recovery ability of CF 3 I/CO 2 was adverse to arc quenching [18]. The V-t characteristics of the CF 3 I/N 2 and CF 3 I/air mixtures were measured by using steep-front voltage, and the CF 3 I/N 2 or CF 3 I/air mixtures containing 60% CF 3 I possessed comparable V-t characteristics to SF 6 [19].…”

Characteristic analysis of CO2 switching arcs under a DC current

“…CO 2 gas is a significant medium either as a puffer gas mixed with other gases or a potential substitute of SF 6 in switchgear equipment. Although a lot of work related to the CO 2 plasma modelling have been published recently [11][12][13][14], there is few literatures that could give satisfactory arc model for CO 2 in switching application.…”