Arc Interruption in Vacuum

Maller, V. N.

doi:10.1016/b978-0-08-024726-7.50011-0

Cited by 10 publications

(5 citation statements)

References 36 publications

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“…Sulfur hexafluoride (SF 6 ) is widely used in gas-insulated power equipment due to its excellent dielectric strength [1], its arc-extinguishing properties [2] and its chemical inertness [3]. Pure SF 6 readily reforms following its dissociation in an electrical discharge, but the metal materials (i.e.…”

Section: Introductionmentioning

confidence: 99%

Theoretical study of the decomposition mechanism of SF₆/Cu gas mixtures

Fu¹,

Wang²,

Yang³

et al. 2018

J. Phys. D: Appl. Phys.

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The compositions of SF 6 arc plasma are contaminated by Cu vapor through electrode erosion and thus affect the performance of the high-voltage SF 6 circuit breaker. But the essential data for chemical kinetic models to study the non-equilibrium compositions of SF 6 /Cu mixtures, namely the decomposition mechanism of SF 6 /Cu mixtures, is still not clear. Besides, SF 6 decomposition products can be used to diagnose insulation faults of GIS and to evaluate the electric life of the SF 6 circuit breaker, but the uncertainty of the decomposition mechanism of SF 6 /Cu mixtures hinders the application of the analysis method of SF 6 decomposition products. Therefore, this work is devoted to investigating the decomposition mechanism of SF 6 /Cu mixtures by means of density functional theory in conjunction with 6-311G(d,p) basis set (for S and F atoms) and Lanl2DZ basis set (for the Cu atom). The optimized molecular structures, harmonic vibrational frequencies and energetic information of reactants, intermediate products (IM), transition states (TS) and products are thoroughly studied. And the complete decomposition pathways of SF 6 /Cu mixtures involving 15 reactions are derived. Detailed potential energy surfaces of SF 6 + Cu decomposition reactions are also depicted as a result. Among all the decomposition pathways, the favorable decomposition reactions of SF 6 + Cu mixtures are found: reaction R1 contributes more than reaction R2 in the decomposition of SF 6 + Cu mixtures due to its lower energy released; reaction R3 is dominant in the decomposition of SF 5 + Cu other than multi-step reactions; the chemical processes of SF 4 + Cu → IM x → TS y (where x stands for 9, 10 and 13, and y denotes 7, 8 and 9) may play the same role in SF 4 + Cu decomposition, but the reaction rate of R6 is higher than other reactions; reaction R9 and R11 are relative favorable among SF 3 + Cu decomposition reactions; reaction R13 is dominant in the decomposition of SF 2 + Cu because of its high potential well. This work hopes to outline a theoretical basis to investigate the non-equilibrium compositions of SF 6 /Cu arc plasma and the SF 6 decomposition products analysis method.

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Section: Introductionmentioning

confidence: 99%

Theoretical study of the decomposition mechanism of SF₆/Cu gas mixtures

Fu¹,

Wang²,

Yang³

et al. 2018

J. Phys. D: Appl. Phys.

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“…Sulphur hexafluoride (SF,) among other gases has long attracted the interest of many scientists and engineers because of its wide applications in the fields of highvoltage engineering and excimer lasers (Teich 1981, Maller and Naidu 1981, Gallagher et a1 1982. Numerous efforts have been made to determine electron swarm data in the gas, in particular the Townsend ionisation coefficient and the attachment coefficient (Bhalla andCraggs 1962, Boyd andCrichton 1971), which are useful for practical applications.…”

Section: Introductionmentioning

confidence: 99%

Transport coefficients of electrons and negative ions in SF₆

Nakamura

1988

J. Phys. D: Appl. Phys.

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A double-shutter drift tube, which was practically the same as that used in measurements of electron swarm parameters in gases, was used to measure the reduced mobility and longitudinal diffusion coefficient of negative ions and the electron drift velocity in SF6. The drift tube proved to be capable of forming three species of negative ion selectively and therefore of determining swarm parameters of the respective negative ions as well as the electrons in the gas. Measurements were carried out over a range of E/N from 20 to 600 Td on negative ions and from 280 to 700 Td on electrons. The three negative ions were identified as F-, SF5- and SF6- according to their reduced mobilities at low electric field.

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“…The gas commonly utilized in corona-stabilized switches is SF 6 [7][8][9], which presents excellent electrical and thermophysical properties. However, the use of SF 6 in switches can lead to severe electrode erosion and significantly impact the switch lifetime, especially in gas switches with highly inhomogeneous fields [19,20].…”

Section: Gas Typementioning

confidence: 99%

Factors and Underlying Mechanisms That Influence the Repetitive Breakdown Characteristics of Corona-Stabilized Switches

Li,

Wang,

et al. 2023

Applied Sciences

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The corona-stabilized switch has the potential to be a high repetition rate pulsed-power switching device, but there has been limited investigation into its repetitive breakdown stability and insulation recovery characteristics. Repetitive breakdowns of gas are characterized by a memory effect, where the subsequent breakdown process is inevitably influenced by the preceding one. However, there are still some issues that require further exploration in the current research on the mechanism of memory effect on repetitive breakdown characteristics. To clarify the factors and mechanisms that affect the repetitive breakdowns of corona-stabilized switches, this paper introduced optical observation methods into the experimental investigation. Through optical–electrical coupled diagnosis, the repetitive breakdown stability and insulation recovery performance of corona-stabilized switches under different working conditions and repetition frequencies were analyzed. The monotonic promoting effect of corona stabilization on switch insulation strength recovery is proposed as well as the non-monotonic and complex regulatory mechanism of corona stabilization on repetitive breakdown stability. The research results provide a theoretical and practical basis for clarifying the mechanism of repetitive corona-stabilized breakdowns and optimizing the design of corona-stabilized switches.

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Arc Interruption in Vacuum

Cited by 10 publications

References 36 publications

Theoretical study of the decomposition mechanism of SF₆/Cu gas mixtures

Theoretical study of the decomposition mechanism of SF₆/Cu gas mixtures

Transport coefficients of electrons and negative ions in SF₆

Factors and Underlying Mechanisms That Influence the Repetitive Breakdown Characteristics of Corona-Stabilized Switches

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Arc Interruption in Vacuum

Cited by 10 publications

References 36 publications

Theoretical study of the decomposition mechanism of SF6/Cu gas mixtures

Theoretical study of the decomposition mechanism of SF6/Cu gas mixtures

Transport coefficients of electrons and negative ions in SF6

Factors and Underlying Mechanisms That Influence the Repetitive Breakdown Characteristics of Corona-Stabilized Switches

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Theoretical study of the decomposition mechanism of SF₆/Cu gas mixtures

Theoretical study of the decomposition mechanism of SF₆/Cu gas mixtures

Transport coefficients of electrons and negative ions in SF₆