Time-resolved radial temperature profiles for 10 kA SF₆arcs

Abstract

Radial temperature profiles for pulsed SF6 arcs burning in high-pressure, approximately 5 bar, supersonic gas flow have been measured in the range 10 kA-1.0 kA. The temperature distribution was obtained from the emission intensities of spectral lines due to excited fluorine and ionized sulphur. The results for currents above 3.5 kA show that the axis temperature is 20000K+or-1000K and is independent of the arc current. Also the temperature profile is essentially parabolic, and any increase in arc current is accompanied by a corresponding increase in arc cross section to maintain a constant current density. Below 3.5 kA the axis temperature falls rapidly with current down to 15500K+or-1000K at kA and the temperature profiles show very steep temperature gradients less than 1 mm from the arc axis.

Arc temperature profile measurement and characteristic analysis on an SF 6 high‐voltage CB

“…A comparison with the results obtained in the PTFE mould is possible to some extent. In [6], the arc temperature profile of a 9 kA current is reported. The temperature decreases from 20,000 to 12,000 K along the radius.…”

“…Moreover, they used the two-line method to calculate the arc temperature. Airey et al [6] and Airey and Abbott [7] maintained a continuous plasma arc in a PTFE nozzle, which under a base pressure of 3.1 bar. Moreover, a high-speed SF6 gas of 6.5 bar was injected into the upstream of the nozzle to simulate the arc chamber condition.…”

“…Moreover, a high-speed SF6 gas of 6.5 bar was injected into the upstream of the nozzle to simulate the arc chamber condition. In [6], the arc temperature is obtained by an atomic fluorine line at 623.9 nm and an ion line of S at 545.4 nm. In [7] copper lines Cu I 510.5 and Cu I 529.3 nm are used to calculate the temperature.…”

Electrode erosion and lifetime performance of a triggered corona-stabilized switch in SF6at a repetition rate of 1 kHZ

“…The high temperatures developed during spark discharge can dissociate SF 6 resulting in a large number of highly reactive ionic species. The nature, population and ionisation state of these dissociated species is strongly dependent on the maximum plasma temperature as well as on the arc-cooling time [17]. Generally, over the temperature range from 3000 to 12000 K, the most abundant species found in a decaying spark plasma are fluorine and sulfur ions [17,18], which react with the electrode surface to form fluorides and sulfides.…”

“…The nature, population and ionisation state of these dissociated species is strongly dependent on the maximum plasma temperature as well as on the arc-cooling time [17]. Generally, over the temperature range from 3000 to 12000 K, the most abundant species found in a decaying spark plasma are fluorine and sulfur ions [17,18], which react with the electrode surface to form fluorides and sulfides. This is an additional factor that makes the erosion mechanism more efficient in SF 6 compared to air, due to the fact that the majority of metal fluorides as well as some metal sulfides are known to be volatile or decompose readily at temperatures higher than 800-1000 °C.…”