High-Current Arc Gap With Ablative Wall: Dielectric Recovery and Wall-Contact Interaction

Lee, A.; Heberlein, J.; Meyer, Tyler

doi:10.1109/tchmt.1985.1136475

Cited by 13 publications

(4 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The plasma, consisting of electrons, ions, and neutrals, will continue to cool provided that the voltage applied across the recovering column does not exceed a critical value. For thermal breakdown, the holdoff voltage is commonly modeled as being inversely proportional to the temperature of the plasma [5], [6] (1)…”

Section: Introductionmentioning

confidence: 99%

“…By approximating the plasma column as a cylindrical geometry, the temperature of the plasma column can be modeled as a decaying exponential with a time constant that represents the rate of cooling [6]. 1521-3331/02$17.00 © 2002 IEEE Using this model, the breakdown strength of a recovering plasma column can be written as [7] (2) Thus, the breakdown strength, , of the complex behavior of the plasma can be modeled by knowing only the initial holdoff voltage at current zero, , and the plasma time constant, .…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Dielectric recovery characteristics of a high current arcing gap

Shea

2002

IEEE Trans. Comp. Packag. Technol.

View full text Add to dashboard Cite

Experimental measurements of the dielectric breakdown strength of an arcing gap after current zero were made to determine the effects of arc chamber venting on the reverse recovery voltage needed to breakdown a recovering gap. The recovery conditions applied closely matched those created in a molded case circuit breaker under power line fault conditions. Three different vent sizes were used to determine the effect of gas pressure on the recovery characteristics of the plasma with recovery time between 170 s to 280 s, and currents from 3 kA to 15 kA . Larger venting, providing increased cooling of the plasma, resulted in increased breakdown strength over the full range of currents. Based on the approximation that the recovering plasma breakdown strength is inversely proportional to plasma thermal temperature, breakdown voltage values were fitted to an exponential model to obtain plasma time constants and the initial holdoff voltage. Comparing these results to curve fits of values showed was a more accurate representation of the data. It is proposed to use values when there is significant post current-zero chamber pressure. These results could be used as a guide to predicting molded case breaker interruption performance, especially for small arc chambers and short gaps.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Dielectric recovery characteristics of a high current arcing gap

Shea

2002

IEEE Trans. Comp. Packag. Technol.

View full text Add to dashboard Cite

show abstract

“…Petcos et al [3] recently reported experimental evidence of particle ejection from the electrodes just after current zero. Lee et al [4] concluded that the formation of droplets during arcing was the major reason for poor gap-recovery performance at a relatively low peak current of 5 kA for Ag-C and Ag-CdO contacts.…”

Section: Introductionmentioning

confidence: 99%

Modelling evaporating metal droplets in ablation controlled electric arcs

Nielsen¹,

Kaddani²,

Zahrai³

2001

J. Phys. D: Appl. Phys.

View full text Add to dashboard Cite

A complete set of equations is proposed to model droplets of molten metal ejected from the contacts in a high voltage circuit breaker of the SF6 filled gas-blast type. The initial speed and diameter of the droplets are varied to characterize their behaviour and study the distribution of the metal vapour. A relation is derived that can be used in simplified arc models such as integral or two-zone models to take the effect of the droplets into account. It is found that, although the influence on usually measured quantities such as pressure and voltage is small, droplets affect velocity and temperature fields in the electric arc significantly and should not be neglected.

show abstract

“…However, for air arcs at atmospheric and higher pressures, the characteristics of droplet splashing erosion are difficult to measure due to the strong arc radiation. To date, there are no reports on the direct observation of air arc splash erosion during arcing, even though it can make a very significant contribution to electrode erosion, and the droplets that are formed are considered to be the main vapor source, which greatly hinders post-arc recovery in circuit breakers [12,13].…”

mentioning

confidence: 99%

Visualization and mechanisms of splashing erosion of electrodes in a DC air arc

Cui

Rong

et al. 2017

J. Phys. D: Appl. Phys.

View full text Add to dashboard Cite

The splashing erosion of electrodes in a DC atmospheric-pressure air arc has been investigated by visualization of the electrode surface and the sputtered droplets, and tracking of the droplet trajectories, using image processing techniques. A particle tracking velocimetry algorithm has been introduced to measure the sputtering velocity distribution. Erosion of both tungsten–copper and tungsten–ceria electrodes is studied; in both cases electrode erosion is found to be dominated by droplet splashing rather than metal evaporation. Erosion is directly influenced by both melting and the formation of plasma jets, and can be reduced by the tuning of the plasma jet and electrode material. The results provide an understanding of the mechanisms that lead to the long lifetime of tungsten–copper electrodes, and may provide a path for the design of the electrode system subjected to electric arc to minimize erosion.

show abstract

High-Current Arc Gap With Ablative Wall: Dielectric Recovery and Wall-Contact Interaction

Cited by 13 publications

References 8 publications

Dielectric recovery characteristics of a high current arcing gap

Dielectric recovery characteristics of a high current arcing gap

Modelling evaporating metal droplets in ablation controlled electric arcs

Visualization and mechanisms of splashing erosion of electrodes in a DC air arc

Contact Info

Product

Resources

About