Study of an ablation-dominated arc in a model circuit breaker

Eichhoff, Daniel; Kurz, Andreas; Kozakov, Ruslan; Gött, Gregor; Uhrlandt, Dirk; Schnettler, Armin

doi:10.1088/0022-3727/45/30/305204

Cited by 33 publications

(32 citation statements)

References 17 publications

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“…4 and 5 plot pressure versus, respectively, the vaporization temperature T vap and the enthalpy necessary to reach vaporization calculated from our data tables. In the pressure range 0.1-10 MPa, we obtained an evaporation temperature of 2975-3315 K. These temperatures are in agreement with [3], [5], and [23] where the vapor temperature is generally taken equal to 3200 K as suggested in [4]. Nevertheless, these authors use a constant enthalpy value independently of the local pressure taken equal to 12 MJ/kg.…”

Section: E Vaporization: Temperature and Enthalpysupporting

confidence: 81%

PTFE Vapor Contribution to Pressure Changes in High-Voltage Circuit Breakers

Gonzalez

Freton

Reichert

et al. 2015

IEEE Trans. Plasma Sci.

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A transient magneto-hydrodynamic model based on @Ansys-Fluent software applied on a high-voltage circuit breaker (HVCB) geometry is presented. The model is turbulent (κ-ε realizable model), and radiation is taken into account by a hybrid model (Discrete Ordinates Method and P1). The insulating medium is SF 6 , and current I rms = 25 kA. An ablation model based on the literature was applied to represent the ablation of the Polytetrafluoroethylene (PTFE) walls. The theoretical and experimental results (pressure, ablation rate, and voltage drop variation) are presented and compared. Several cases were considered: no ablation (ceramic walls), ablation only from downstream parts, and ablation from upstream parts of HVCB walls. The corresponding pressure variations are presented. In order to explain the pressure increase, some additional quantities such as mass flow rate and energy integrated into one section of the heating channel are given. The results show that even if the mass of PTFE ablated is small, the pressure increase is due to the energy input from the vapor.Index Terms-Computational fluid dynamic (CFD) model, heating volume, high-voltage circuit breaker (HVCB), pressure increase, SF 6 and C 2 F 4 vapors.

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Section: E Vaporization: Temperature and Enthalpysupporting

confidence: 81%

PTFE Vapor Contribution to Pressure Changes in High-Voltage Circuit Breakers

Gonzalez

Freton

Reichert

et al. 2015

IEEE Trans. Plasma Sci.

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“…shown. The red and the black curve were obtained for the slit position inside the PTFE nozzle and the heating volume, respectively, from CFD simulation (CFD-ACE+ software suite by the ESIGroup) of the discharge according to [17]. Comparison of simulation results for the heating volume (black) with our measurements (dashed blue) resulted in good agreement concerning the shape of the curve.…”

Section: Video Observation and Flow Reversalmentioning

confidence: 68%

“…In setup (b), the distance between the two nozzles was about 4 mm forming a heating channel. The line of sight used in [17] was along the heating channel, i.e. in central position between the nozzles where turbulent gas flow in radial direction cannot be avoided and may disturb the observation of radial profiles.…”

Section: Geometry Of Electrodes and Nozzlesmentioning

confidence: 99%

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Ablation-Dominated Arcs in CO2 Atmosphere - Part I: Temperature Determination near Current Zero

Methling¹,

Khakpour²,

Götte³

et al. 2020

Preprint

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Wall–stabilized arcs dominated by nozzle–ablation are key elements of self–blast circuit breakers. In the present study, high–current arcs were investigated using a model circuit breaker (MCB) in CO2 as gas alternative to SF6 and in addition a long polytetrafluoroethylene nozzle under ambient conditions for stronger ablation. The assets of different methods for optical investigation were demonstrated, e.g. high-speed imaging with channel filters and optical emission spectroscopy. Particularly the phase near current zero (CZ) crossing was studied in two steps. In the first step using high-speed cameras, radial temperature profiles have been determined until 0.4 ms before CZ in the nozzle. Broad temperature profiles with a maximum of 9400 K have been obtained from analysis of fluorine lines. In the second step, the spectroscopic sensitivity was increased using an intensified CCD camera, allowing single-shot measurements until few microseconds before CZ in the MCB. Ionic carbon and atomic oxygen emission were analyzed using absolute intensities and normal maximum. The arc was constricted and the maximum temperature decreased from &gt;18000 K at 0.3 ms to about 11000 K at 0.010 ms before CZ. The arc plasma needs about 0.5-1.0 ms after both the ignition phase and the current zero crossing to be completely dominated by the ablated wall material.

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“…Optical techniques can be loosely divided into two categories: those that measure the index of refraction and those that measure the emission spectrum. The latter techniques provide useful information about the temperature distribution in the arc during the high-current phase [16,17]. In the study of current interruption, the phase just before, at, and immediately after the zero crossing determines if the current is interrupted.…”

Section: Introductionmentioning

confidence: 99%

Measuring Density Profiles of Electrons and Heavy Particles in a Stable Axially Blown Arc

et al. 2017

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Two-color spatial carrier wave interferometry employing pulsed 532-and 671-nm lasers is used to measure the electron-density and heavy-particle-density profiles in the stagnation point of a stable, axially blown arc in argon for currents of 50 to 200 A and stagnation point pressures of 0.2 to 16 bar. This technique takes advantage of the fact that the free-electron contribution to the refractive index depends strongly on the wavelength, while that of the heavy particles does not. The high spatial resolution achieved allows the hot core of the arc to be readily distinguished from the surrounding boundary layer. A custom-built test device is used to ensure flow conditions that lead to a stable, axisymmetric arc; this permits the reconstruction of the density and temperature profiles using a single projection (interferometric image) of the refractive-index distribution through the arc (at two wavelengths). The arc radius determined from the heavy-particle density decreases with increasing stagnation pressure and increases with the current. These measurements are in good agreement with a simple axially blown arc model taking into account Ohmic heating, radiation losses, and enthalpy flow for core temperatures of approximately 16 500 K. The measured electron density at the center of the arc agrees well with a prediction based on local thermodynamic equilibrium.

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Study of an ablation-dominated arc in a model circuit breaker

Cited by 33 publications

References 17 publications

PTFE Vapor Contribution to Pressure Changes in High-Voltage Circuit Breakers

PTFE Vapor Contribution to Pressure Changes in High-Voltage Circuit Breakers

Ablation-Dominated Arcs in CO2 Atmosphere - Part I: Temperature Determination near Current Zero

Measuring Density Profiles of Electrons and Heavy Particles in a Stable Axially Blown Arc

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