Plasma Physics and Technology Journal
Volume 6 (2019)
Number 1
Metallic Nanoparticles Generation by Repetitive Pulsed Laser for Applications in Bio-Medicine
Restuccia N.1, Silipigni L.1, Cordaro M.2, Torrisi L.1
1Dipartimento di Scienze Matematiche e Informatiche, Scienze Fisiche e Scienze della Terra, MIFT, Università di Messina, V.le F. Stagno d'Alcontres 31, 98166 S. Agata, Messina, Italy
2Dip.to di Scienze Chimiche, Biologiche, Farmaceutiche e Ambientali,Università di Messina, Italy
An Nd:YAG pulsed laser operating at the 1064 nm wavelength, the 3 ns pulse duration, the 1010 W/cm2 intensity and the 10 Hz repetition rate is employed to irradiate biocompatible metallic targets based on Au, Bi and Ag placed in water. The laser-matter interaction produces nanometric spherical particles. The concentration of the solution with nanoparticles is controllable by the laser parameters, the ablative emission process, the irradiation time and the water's volume. Generally, nanoparticles of about 10 nm in size and concentrations of the order (0.1 ÷ 10) mg/ml are prepared to be injected in cell cultures or in living systems (mice). The nanoparticles introduction in the extra and intracellular cellular liquids improves the bio-imaging of the tissue and organs by using fluorescence techniques. Moreover, if these nanoparticles are concentrated in tumour cells, they make possible high efficiency radio-therapy and thermal-therapy treatments, as it will be presented and discussed.
Keywords: Laser ablation in water, nanoparticles, imaging, therapy
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Output Current Control System of a High Voltage Electric Pulse Generator for Plasma Excitation
Godun D. V., Bordusau S. V., Budzko G. P.
Belarusian State University of Informatics and Radioelectronics, P. Brovki 6, 220013, Minsk, Belarus
A control and pulse discharge current limiting system integrated into an AC/DC converter and pulse modulator of a high voltage pulse generator have been developed. The peculiarity of such system\textquotesingle s operation is the stabilization of the power supplied to the discharge and the correction of the width of output electric pulses towards decrease upon reaching the specified pulsed current amplitude value. The system enables the pulse generator to work in the modes close to the "short circuited load" mode. In this case the driving module of a composite IGBT key performs the correction of the working pulse width and blocks the pulse generator operation if needed. The suggested circuit design solutions allow using the generator in a wide range of electric plasma-forming parameters' modes and working with various types of vacuum gas discharge systems.
Keywords: output current, control, electric pulses, plasma load
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Experimental Study on Dynamic Welding of AgW60, CuW60 and Cu Contact Materials in Symmetrical and Asymmetric Pairings at DC 270V/200A
Liao Yuan1, Zhang Dandan1, He Mengbing1, Makoto Hasegawa2, Li Zhenbiao1
1State Key Laboratory of Advanced Electromagnetic Engineering and Technology, School of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
2Chitose Institute of Science and Technology, Chitose, Hokkaido, 066-8655, Japan
Experiments were conducted for AgW60, CuW60 and Cu contacts and their different pairings at DC 270V/200A in a surrounding atmosphere of carbon dioxide or nitrogen. Welding resistances, average welding forces and relationships between welding forces and the number of operations required for welding were measured and analyzed. The anti-welding ability of the three materials in their symmetric pairings in carbon dioxide and nitrogen can be ranked as AgW60>Cu>CuW60. The "intermediate effect" occurs in the anti-welding properties of the asymmetric pairings. The relationships between the number of operations required for welding and the average welding force is approximately in an inverse proportional function.
Keywords: surrounding atmosphere, contact material, DC, welding, welding force, AgW60, CuW60, Cu
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Investigations on the Effect of the Nozzle Material on the Interruption Capability of a Medium Voltage Load Break Switch
Bendig M.1, Krampert T.1, Götte N.1, Kalter A.2, Schaak M.2, Ermeler K.3
1Institute for High Voltage Technology, RWTH Aachen University, Schnikelstr. 2, 52056 Aachen, Germany
2Siemens AG, Energy Management Division, Carl-Benz-Str. 22, 60386 Frankfurt am Main, Germany
3Siemens AG, Energy Management Division, Nonnendammallee 104, 13629 Berlin, Germany
In the process of substituting sulphur hexafluoride in medium voltage load break switches by atmospheric gases, the inferior arc quenching capabilities of possible substitutes have to be compensated. By introducing a polymer nozzle into the switching gap of a load break switch, the interruption capability can be enhanced as the ablated nozzle material changes the composition of the arc plasma. In this contribution the interruption capability of a model load break switch is investigated using different nozzle materials. The results show a good interruption capability when using polypropylene and polyamide 6.6 for high blowing pressures. Polytetrafluorethylene shows good results across a wide blowing pressure range. Polylactide has the lowest interruption capability among the polymers in this work.
Keywords: load break switch, nozzle material, ablation, alternative gases
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Control of Diffuse Vacuum Arc Using Axial Magnetic Fields in Commercial High Voltage Switchgear
Giere S.2, Heinz T.2, Lawall A.1, Stiehler C.1, Taylor A. D.1, Wethekam S.2
1Siemens AG, Smart Infrastructure, Rohrdamm 88, 13623 Berlin, Germany
2Siemens AG, Gas and Power, Nonnendammallee 104, 13623 Berlin, Germany
During the development of a commercial vacuum interrupter for application in HV switchgear at a rated voltage of 145kV, we investigated the behavior of vacuum arcs controlled by axial magnetic fields (AMF). AMF arc control is already extensively used in medium voltage (1-52kV) applications, the key difference is the 2-3 times larger contact gap and the corresponding reduction of the AMF strength for HV applications. We conducted several stress tests with short circuit currents up to 40kA, thus not only testing the interrupting capability, but also the electrical endurance of such a contact system. We also investigated the dielectric behavior of the vacuum interrupter by testing the capacitive switching duty. Despite the large number of operations, the contacts showed a minimal amount of contact erosion and damage and demonstrated behavior very similar to the extensive experience with MV vacuum interrupters. In line with simulation results, we conclude that even at high contact gaps and currents, a diffuse vacuum arc was maintained which distributed the arc energy evenly over the contacts.
Keywords: High Voltage, Vacuum Interrupter, Vacuum Arcs
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Nozzle Wear and Pressure Rise in Heating Volume of Self-blast Type Ultra-high Pressure Nitrogen Arc
Abid F.1, Niayesh K.1, Støa-Aanensen N.2
1Department of Electric Power Engineering, Norwegian University of Science and Technology, 7491, Trondheim, Norway
2SINTEF Energy Research, 7465, Trondheim, Norway
This paper reports on experiments with ultra-high pressure nitrogen arcs in a self-blast type switch design. The effect of filling pressure on nozzle mass loss and pressure-rise in the heating volume is investigated. An arc current peak of 130\,A at 190\,Hz, and a fixed inter-electrode gap of 50\,mm are used. The arc burns inside a polytetrafluoroethylene nozzle with a gas outflow vent in the middle. Three different nitrogen filling pressures were tested: 1, 20 and 40\,bar, which also covers the supercritical region. To study the effect of vent size on blow pressure near current zero, three different vent dimensions were investigated. The energy deposited in the arc increases with the filling pressure. It is observed that the pressure-rise in the heating volume is linked to the filling pressure, while the vent size plays a crucial role in the blow pressure near current zero. The nozzle mass loss per unit energy deposited in the arc is found to be independent of the filling pressure.
Keywords: ultrahigh pressure arc, nozzle wear, supercritical fluid, arc discharge
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Thermal Plasma of Electric Arc Discharge Between Cu-Cr Composite Electrodes
Veklich A.1, Boretskij V.1, Kleshych M.1, Fesenko S.1, Murmantsev A.1, Ivanisik A.1, Khomenko O.2, Tolochyn O.2, Bartlova M.3
1Taras Shevchenko National University of Kyiv, 64/13, Volodymyrska str., Kyiv, Ukraine
2Frantsevich Institute for Problems of Materials Science NAS of Ukraine, 3, Krzhizhanivsky str., Kyiv, Ukraine
3Brno University of Technology, Technicka 10, Brno, Czech Republic
This work deals with investigations of model plasma source realised as electric arc discharge in gas atmosphere between Cu-Cr composite electrodes. Radial distributions of temperature and electron density in arc plasma column were studied by optical emission spectroscopy. The content of electrode metals' vapours in discharge was calculated on the base of experimentally obtained plasma parameters as initial data. So, in this way the erosion properties of such composition can be determined.
Keywords: optical emission spectroscopy, plasma of arc discharge, erosion of surface electrode, composite materials, electrical contact
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Impact of Stark shifts on the radiation cooling of Cu-dominated plasmas
Corfdir P., Lantz G., Abplanalp M., Delachaux T., Kassubek F., Sütterlin P., Bator M.
ABB Corporate Research, Segelhofstrasse 1K, 5405 Baden-Dättwil, Switzerland
We study the impact of Stark line shifts reported recently for Cu I transitions on the radiative cooling of Cu-dominated plasmas. The observed detuning in absorption between the hot core and cold shell of the arc leads to a reduction in radiation reabsorption compared to the case where Stark line shifts are neglected. Using a modeling based on a phenomenological treatment of the Stark line shift, we show that this reduction is below 2%.
Keywords: Cu plasmas, Stark effect, radiation cooling, radiative transfer equation, spectroscopy
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3D CFD arc fault simulation in gas-insulated switchgears
Reichert F., Petchanka A.
Siemens AG, Nonnendammallee 104, 13629 Berlin, Germany
Arc fault processes can lead to strong damages in gas--insulated switchgears and have to be considered in the development process. In order to reduce test costs, the development of overpressure protection systems can be supported by CFD arc fault simulations. The paper deals with the modelling and simulation of arc fault processes in gas--insulated switchgears. The developed simulation tool takes into account a three--dimensional arc model and the opening of a rupture disc during the arc fault process. The influence of different insulating media as e.g. SF$_6$, Air and CO$_2$ on the arc fault process has been investigated.
The simulation model has been validated by measured signals for pressure build-up and arc voltage.
Keywords: gas-insulated switchgear, internal arc, CFD arc fault simulation, modelling, validation
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Breakdown in CO2/O2 and CO2/O2/C2F4 mixtures at elevated temperatures in the range 1000-4000K
Seeger M.1, Votteler T.1, Pancheshnyi S.2, Carstensen J.1, Garyfallos A.1, Schwinne M.1
1 ABB Switzerland Ltd., Corporate Research, Segelhofstrasse 1K, CH-5405 Baden-Dättwil, Switzerland
2 ABB Switzerland Ltd., Business Unit Transformers, 8048 Zürich-Altstetten, Switzerland
CO2 is a promising gas for replacement of SF6 in high voltage circuit breakers. The electric breakdown in CO2 and mixtures with C2F4 from PTFE nozzles is, however, still not fully understood. To understand the electric breakdown in CO2 and mixtures with C2F4 from PTFE nozzles fundamental parameters like the temperature and pressure dependence of critical electric fields are needed. Data on critical fields is usually available based on simulations only and experimental validation is lacking so far. Our present contribution aims to close this gap and presents experiments where the breakdown fields in uniform and weakly non-uniform electric fields are determined at various temperatures and pressures. The gas temperatures were estimated from measurements with pyrometers. The results are compared to theoretical predictions.
Keywords: electric breakdown, CO2, C2F4, dielectric recovery
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Formation of the upstream region in HV gas blast interrupters with synchronous gas injection
Kurakina N. K.1,2, Frolov V. Ya.1, Tonkonogov E. N.1
1Peter the Great Saint-Petersburg Polytechnic University, Polytechnicheskaya 29, St.-Petersburg 195251, Russia
2Institute for Electrophysics and Electric Power of Russian Academy of Sciences, Dvortsovaya nab., 18, St.-Petersburg, 191186, Russia
The problem of a synchronous gas injection at the vicinity of current zero for high voltage gas blast circuit breakers~(GCB) is discussed. The basic aim of the investigation is to improve the efficiency of arc quenching in GCB by increasing interruption ability without changes in drive parameters. The paper reviews the upstream region influence on the interruption capability, gas injection - mass flow interactions at the region between electrical contact and nozzle throat of GCB. Numerical simulation is used to calculate gas-dynamics parameters at the upstream region of mono-flow GCB. The mass discharged as a result of the synchronous gas injection can rapidly modify both the density and pressure at the nozzle throat, regulate flow velocity in the research region. The selected method of the gas injection effects the breaking performance in the arc quenching device strongly. Some calculation results are presented.
Keywords: high-voltage gas blast interrupters, air blast circut breakers, interruption capability, arc quenching, synchronous gas injection, gas-dynamics, numerical simulation, OpenFOAM
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Estimation of the Intensively Blasted Electric Arc Model Sensitivity to Selected Variables
Senk J., Laznickova I., Jakubova I., Coufal O.
Faculty of Electrical Engineering and Communication, BUT, Technicka 12, 616 00 Brno, Czech Republic
Results of measurements carried out on the fabricated experimental modular-type arc heater serve as input data for the designed simplified model of the intensively blasted electric arc burning in argon inside the cylindrical arc heater's anode channel. The axial dependence of the arc temperature and radius is expressed using the exponent, the current density on the cathode tip and the arc temperature at the end of the near-cathode boundary layer. These quantities form the vector of state variables that is sought to minimize the value of the objective function expressing the deviations between measured and computed values. On a typical example, the paper demonstrates the sensitivity of the modelling to individual state variables.
Keywords: electric arc, arc heater, argon, modeling
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Modelling and experimental investigations of DC electric arcs in argon and carbon dioxide
Mohsni C.1,2, Baeva M.1, Franke St.1, Gortschakow S.1, Gonzalez D.1, Araoud Z.2, Charrada K.2
1Leibniz Institute for Plasma Science and Technology, Felix-Hausdorff-Str. 2, 17489 Greifswald, Germany
2National School of Engineering of Monastir, 5000 Rue Ibn Jazzar, Monastir 5035, Tunisia
In this work an arc model is employed along with electric and spectroscopic measurements to study DC electric arcs in Ar and CO2. The model is aimed at describing the arc and the electrodes. Simulation and experimental results are shown for currents between 150 A and 210 A.
Keywords: thermal plasma, electric arcs, plasma-electrode interaction, plasma diagnostics
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Comparative studies of low-intensity short-length arcs
Baeva M.1, Siewert E.2, Uhrlandt D.1
1Leibniz Institute for Plasma Science and Technology, Felix-Hausdorff-Strasse 2, 17489 Greifswald, Germany
2Linde AG, Geschäftsbereich Linde Gas, Carl-von-Linde-Strasse 25, 85716 Unterschleissheim, Germany
We present results obtained by two non-equilibrium modelling approaches and experiments on low-intensity short-length arcs in argon at atmospheric pressure. The first one considers a quasi-neutral arc column combined with boundary conditions on the electrodes based on the energy balance in the space-charge sheaths. The second approach applies a unified description over the entire gap and solves the Poisson equation for the self-consistent electric field. The experiments provide the arc voltage.
Keywords: non-equilibrium, unified, arc plasma, modelling, experiment
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Estimation of Current Density Using High-Speed-Camera Recordings in a Model Spark Gap during Surge Currents
Kopp T. H., Peters E., Kurrat M.
Institute for High Voltage Technology and Electrical Power Systems, Technische Universität Braunschweig, Braunschweig, Germany
For experimental investigations of short time plasma in spark gaps, as used in surge protective devices, high-speed camera recordings are used frequently. The analysis of these recordings provides further details regarding the plasma state and distribution. These deduced details are used to assist research and development processes.
To increase the benefit of high-speed camera recordings an empirical model is presented to improve the picture analysis. In this model the recorded radiation intensity is empirically related to the current density within a spark gap. Therefore a specially adapted model spark gap was developed and tested. In this model spark gap areas with homogenous current densities occur. These current densities are determined in the experimental setup through current measurements with separated electrodes. Additionally, the relative radiation intensity between the electrodes is identified using high-speed camera recordings. An empirical correlation between these two measurement values was found and is discussed.
It confirmed that the determined correlation improve the mostly intuitive interpretation of high speed camera recordings in spark gaps.
Keywords: spark gap, plasma, surge protective device, high speed camera, current density, narrow gap
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3D analysis of low-voltage gas-filled DC switch using simplified arc model
Gortschakow S.1, Gonzalez D.1, Yu S.2, Werner F.2
1Leibniz institute for plasma science and technology (INP), Felix-Hausdorff-Strasse 2, 17489 Greifswald, Germany
2TDK Electronics, Gradestrasse 48-50, 12347 Berlin, Germany
Electro-magnetic simulations have been used for the visualization of distribution of Lorentz force acting on a DC switching arc in low-voltage contactor. A simplified plasma model (black-box model) was applied for the description of arc conductivity. Arc geometry was gained from the high-speed camera images. Influence of arc position, arc current and of external magnetic field has been studied. Results have been compared with optical observations of the arc dynamics.
Keywords: black-box model, Lorentz force, arc dynamics, 3D simulations
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Investigation of the arc characteristics of switching DC arcs on hydrogen containing gas mixtures
Gonzalez D.1, Gortschakow s.1, Yu S.2, Werner F.2
1Leibniz institute for plasma science and technology (INP), Felix-Hausdorff-Strasse 2, 17489 Greifswald, Germany
2TDK Electronics, Gradestrasse 48-50, 12347 Berlin, Germany
The characteristics of switching DC current arcs in hydrogen containing gas mixtures under pressure were investigated using a model chamber. The switching device consists of an electro-mechanic double breaker unit with copper contacts. High-speed imaging and spectroscopy were used to observe and to characterize the switching arc. The experiments indicate how the dynamic interaction of an external magnetic field with a high-pressure discharge causes an elongation and twisting of the arc-channel and consequently a voltage increase. Comparative measurements with and without external magnetic field indicate a strong influence of this factor. Cu and N lines together with strongly broadened H lines were observed.
Keywords: arc behaviour, external magnetic fields, gas filled contactors, hydrogen, overpressure
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Interruption of medium-voltage direct-currents by separation of contact elements in mineral oil using an ultra fast electro-magnetic actuator
Jugelt S., Leu C.
Research Unit High-Voltage Technologies, Technische Universität Ilmenau, Gustav-Kirchhoff-Strasse 1, 98693, Ilmenau, Germany
The increasing usage of medium-voltage direct-current in upcoming electrical energy grid topologies requests novel solutions for MVDC switching. The interruption of direct-currents is accomplished by enforcing a current zero crossing by adequate means and preventing reignition due to the recovering dc voltage. This paper evaluates the rapid separation of the contact elements in mineral oil leading to a liquid flow around the contact elements and the switching arc. The energy turnover of dielectric liquids interacting with an electric arc is considerably higher leading to heavily increased arc voltages compared to dielectric gases. This paper confirms results of earlier publications and carries them further towards a possible usage in an MVDC switching or protection device. Thus a contact arrangement surrounded by mineral oil in combination with an ultra fast electro-magnetic actuator is introduced and performed measurements are discussed.
Keywords: dc interruption, bulk oil, dc switching arc, mvdc, mvdc protection device
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Numerical investigation, including experimental validation, of an axially blown, stable arc in argon
Galletti B.1, Kassubek F.1, Buffoni M.1, Carstensen J.1, Stoller P. C.2
1ABB Switzerland Ltd., Corporate Research, 5405 Baden-Daettwil, Switzerland
2ABB Switzerland Ltd., Technology Center - Interrupter Development, 5401 Zurich, Switzerland
In this work we present the outcome of a numerical validation study conducted with an arc model developed within a computational fluid dynamics (CFD) tool. The numerical investigations were aimed at reproducing the spatially resolved temperature data obtained with an experiment in which an axially symmetric argon arc was established in the observation region. The full absorption spectrum has been computed for argon and then compressed with minimum loss of information to a relatively small set of bands. The latter has been used for solving the radiative transfer equation in a computationally affordable, yet accurate way. The comparison between the arc temperature simulated with the reduced absorption data and the measured one is presented.
Keywords: high-voltage circuit breaker, radiation, optical diagnostics, arc simulation, validation
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Analysis of C2 Swan Bands in Ablation-Dominated Arcs in CO2 atmosphere
Methling R.1, Franke St.1, Götte N.2, Wetzeler S.2, Uhrlandt D.1
1Leibniz Institute for Plasma Science and Technology (INP), Felix-Hausdorff-Str. 2, 17489 Greifswald, Germany
2Institute for High Voltage Technology, RWTH Aachen University, Schinkelstrasse 2, 52056 Aachen, Germany
A model circuit breaker in a high-pressure chamber filled with CO2 atmosphere is used to operate a wall-stabilized arc of several kilo-amperes between tungsten-copper electrodes surrounded by polytetrafluoroethylene nozzles. Optical emission spectroscopy (OES) is carried out via quartz plates inserted into the nozzles using a combination of an imaging spectrometer either with a high-speed video camera or with an ICCD camera. Depending on the nozzle geometry and the current, continuum from C2 Swan bands was detected as absorption as well as emission pattern. After current zero, optical absorption spectroscopy (OAS) using a xenon flashlamp as broadband background radiator was applied. An absorption around 493 nm was detected and attributed to CuF molecules. The study proofs the existence of C2 in the active phase and the formation of CuF near to current zero.
Keywords: ablation, switching arc, spectroscopy, PTFE, CO2
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Optical Emission Spectroscopy of Magnethron Discharge Ar/Cu Plasma
Murmantsev A.1, Veklich A.1, Boretskij V.1, Shapovalov A.2, Kalenyuk A.3
1Taras Shevchenko National University of Kyiv, 64/13, Volodymyrska str., Kyiv, Ukraine
2V. N. Bakul Institute for Superhard Materials, National Academy of Sciences of Ukraine, Avtozavodska Str., 2, Kyiv 04074, Ukraine
3G. V. Kurdyumov Institute for Metal Physics, National Academy of Sciences of Ukraine, Academician Vernadsky Blvd., 36, Kyiv 03142, Ukraine
Plasma parameters (excitation temperature and electron density) of pulsing magnetron discharge is studied by optical emission spectroscopy. Such discharges are usually used as effective sources in sputtering or deposition processes. Vapor admixtures in argon plasma define mainly the temperature and electron density in such discharges. This is the feature, which is typically takes place in plasma of discharge between contacts/electrodes in switching devices of electric technology circuits.
Keywords: magnetron, argon plasma, spectroscopy, Boltzmann plots
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Pyrotechnic Switch with Fuse Function
Ehrhardt A.1, Wolfram S.2
1DEHN + SÖHNE GmbH + Co.KG., Hans-Dehn-Strasse 1, 92318 Neumarkt, Germany
2Institute for Electric Power and Control Engineering, Technische Universität Ilmenau, Gustav-Kirchhoff-Str. 1, 98693 Ilmenau, Germany
The article will present the combination of a low-voltage fuse with a pyrotechnic switch in compact design. The limited switching capacity of the very simple pyrotechnic switch is increased considerably when combined with a fuse which has classical passive time/current characteristic and high switching capacity. FEM calculations will demonstrate the functional principle and the passive and active characteristics of functional models will be examined. Switching behaviour with different overcurrents in case of passive or active triggering will be discussed on the basis of measuring results. The behaviour of such a fuse with high impulse currents will also be presented.
Keywords: fuse, pyrotechnic switch, impulse current, numerical simulation, SPD
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Diagnostics of plasma pencil discharge for chemical analysis
Slavicek P.1, Hrdlicka A.2, Dvorakova M.2, Kanicky V.2
1Department of Physical Electronics, Faculty of Science, Masaryk University, Kotlarska 267/2, 61137 Brno, Czech Republic
2Department of Chemistry, Faculty of Science, Masaryk University , Kotlarska 2, 61137, Brno, Czech Republic
We present diagnostics of plasma pencil discharge as alternative excitation source for analytical chemistry. The plasma pencil is special type of rf plasma nozzle at atmospheric pressure. Through this nozzle flows working gas argon with aerosol. The aerosol sample introduction system employed a double pass Scott spray chamber with a pneumatic concentric nebulizer. The parameters of the plasma were calculated by optical emission spectroscopy.
Keywords: plasma pencil, atmospheric pressure plasma, OES, chemical analysis
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Self-consistent modeling of electrode motion in a model circuit breaker
Fuchs R.
Institute for Energy Technology, HSR University of Applied Sciences Rapperswil, 8640 Rapperswil, Switzerland
Numerical simulations of low-voltage circuit breakers require a coupled solution of gas flow, electromagnetism, electrical circuit, and other aspects. Including electrode motion is challenging because the computational grid is deformed and data is to be exchanged among dedicated solvers. A central issue is to keep them synchronized. This is addressed with a single framework that allows for a continuously morphing grid and accounting for the cumulative effects of mechanics, Lorentz force, and gas pressure. It is shown that gas pressure has negligible effect.
Keywords: circuit breaker, electrical arc simulation, self-consistent, rigid body motion
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Influence of varying gaps between TMF contacts on constricted high current vacuum arcs
Kuehn B.1, Weber B.1, Gentsch D.2, Kurrat M.1
1Institute for High Voltage Technology and Electrical Power Systems, Technische Universitaet Braunschweig Schleinitzstrasse 23, 38106 Braunschweig, Germany
2ABB AG, Calor Emag Mittelspannungsprodukte, Oberhausener Str. 33, 40472 Ratingen, Germany
The behavior of high current arcs in vacuum circuit breaker (VCB) is interesting for research and industrial development purpose which lead to further products. To improve the interruption capability of VCB, two approaches to control the arc have been proven successful. Applying transversal magnetic fields (TMF) on the arc is use for industrial VCB in medium voltage ranges. For greater gap distances the behavior of the arc is less thoroughly investigated. In this paper, the appearance of metal vapor arcs drawn by common TMF contacts in a vacuum-test-interrupter is investigated. An adapted drive mechanism enables to interrupt a fixed current with varying gaps from 5 to 25 mm and a constant opening time. Breaking operations with a 50 Hz current are observed with a high speed camera. With increasing gap distance a changed arc appearance can be observed. The goals of this work are to be understood as a feasibility study for optical evaluation methods for vacuum arcs under TMF.
Keywords: vacuum circuit breaker, VCB, TMF, constricted arcs, automatized evaluation
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Number 2
Investigation of the Method of Dynamic Microwave Power Redistribution in a Resonator-Type Plasmatron
Madveika S., Bordusau S., Zemlyakov A., Lushakova M.
Belarusian State University of Informatics and Radioelectronics, P.Brovki 6, 220013 Minsk, Belarus
The investigation results of a dynamic microwave power fmicrowave = 2.45±0.05 GHz redistribution in a 9000 cm3 reaction-discharge chamber of a microwave resonator-type plasmatron are presented. In order to redistribute the microwave power, a rotating metallic four-blade L-form dissector placed above the reaction-discharge chamber was used. The microwave power in the local points at the axis of the chamber with plasma and without it was measured applying the "active probe" method. During the experiments the chamber contained silicon wafers. Periodical interchange of maximum and minimum microwave power values along the chamber axis was established experimentally. Note, when the dissector was rotating, the range of maximum and minimum "active probe" values dispersion decreased. It has been established that during the dissector rotation the microwave power in the local discharge areas changes with periodic repetition every quarter of revolution.
Keywords: microwave plasma, microwave power, redistribution, dissector
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Investigation of conversion process of SiCl4 + CCl4 mixture by RF (40.68 MHz) arc discharge
Kornev R.1, Sennikov P.1, Nazarov V.1,2, Kut'in A.1, Plekhovich A.1
1G.G. Devyatykh Institute of Chemistry of High-Purity Substances of RAS, 49 Tropinin Str., Nizhny Novgorod, 603951, Russia
2Institute of Applied Physics of RAS, 46 Ulyanova Str., Nizhny Novgorod, 603950, Russia
A contracted RF (40.68 MHz) arc discharge of atmospheric pressure, stabilized between two rod electrodes, was used to obtain trichlorosilane by the reaction of hydrogen reduction of silicon tetrachloride (SiCl4). In model mixtures of macro-composition in the ratio H2/SiCl4/CCl4=10/1/1, it was shown that C and SiC are the main solid-phase product which are deposited on the surface of electrodes in the form of dendrides. The temperature of the ends of the electrodes determined using emission thermometry is 1600 K. The thermodynamic analysis of H2+SiCl4+CCl4 system confirms that the formation of C and SiC occurs in the temperature range of 1600 K. The deposition of solid-phase products occurs on the electrodes in the zone of high electric field strength.
Keywords: RF arc discharge, conversion process of SiCl4+CCl4, thermodynamic analysis
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A computational model for high current density arc plasmas
Alija M., Kurrat M.
Faculty of Electrical Engineering, Information Technology, Physics, Technische Universität Braunschweig, 38106 Braunschweig, Germany
A computational model for high current density arc plasmas is developed. Under the assumption of thermodynamic equilibrium the arc plasma is described as a compressible laminar fluid based on the magnetohydrodynamic (MHD) equations and the transport and thermodynamic properties of air. The arc plasma is studied in time and space on macroscopic values such as the temperature and the pressure. The simulation results are discussed and future research work is identified addressing the scientific domain of high current density arc plasmas.
Keywords: computational plasma physics, high current density arc plasma, magnetohydrodynamics
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Influence of resonance radiation transport on chemical equilibrium in an argon arc
Gortschakow S.1, Kalanov D.2, Golubovskii Yu.3
1Leibniz Institute for Plasma Science and Technology (INP), Felix-Hausdorff-Strasse 2, 17489 Greifswald, Germany
2Leibniz Institute of Surface Engineering (IOM), Permoserstrasse 15, 04318 Leipzig, Germany
3Saint-Petersburg State University, Ulyanovskaya 3, 198504 St. Petersburg, Russia
Deviations from chemical equilibrium in argon arc plasma are analysed by means of collisional-radiative model. Corresponding comprehensive kinetic scheme has been developed and applied form study of free-burning arc at the conditions typical for welding applications. While the natural lifetime have been used for radiation emitted from highly excited argon states, the resonance radiation was described taking into account the radiation transport effects. Resulting spatial distributions of excited argon atoms are compared for the cases of LTE and two-temperature plasma using different approaches for the description of the resonance radiation transport.
Keywords: radiation transport, collisional-radiative model, argon arc
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Analysis of erosion resistance of CuC arcing contacts manufactured by plasma spraying technology
Derevyankin P.1, Frolov V.1, Gonzalez D.2, Gortschakow S.2, Methling R.2, Uhrlandt D.2
1Peter the Great St. Petersburg Polytechnic University, Polytechnicheskaya 29, 195251 St. Petersburg, Russia
2Leibniz Institute for Plasma Science and Technology (INP), Felix-Hausdorff-Strasse 2, 17489 Greifswald, Germany
Results of the erosion resistance study of the CuC electrodes manufactured by plasma spraying technology are presented. The diagnostics has have been performed by means of high-speed camera technique and optical emission spectroscopy which has been synchronised with electrical diagnostics. After the load material analyses, namely determination of mass loss and analysis of micro sections, have been done. It has been found that the erosion rate depends on conditions applied for the formation of coating layer, which was deposited either in air or in argon plasma. Furthermore, the erosion rate is significantly lower in the case of air plasma spraying.
Keywords: electrode erosion, low-voltage circuit breaker, coating
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Application of RF (40.68 MHz) arc discharge for plasma chemical conversion of volatile chlorides of silicon and germanium
Kornev R.1, Sennikov P.1, Nazarov V.1,2, Sukhanov A.1, Shabarova L.1
1G.G. Devyatykh Institute of Chemistry of High-Purity Substances of RAS, 49 Tropinin Str., Nizhny Novgorod, 603951, Russia
2Institute of Applied Physics of RAS, 46 Ulyanova Str., Nizhny Novgorod, 603950, Russia
The processes of hydrogen reduction of silicon and germanium chlorides are studied under RF conditions (40.68 MHz) of contracted atmospheric pressure arc discharge stabilized between two rod electrodes. The main gas-phase and solid products of plasma-chemical transformations are determined. Using the hydrogen reduction of SiCl4 as an example, the numerical simulation of gas-dynamic and heat exchange processes for this type of discharge was performed. The studies were carried out for the optimal conditions for obtaining trichlorosilane using modern computational technologies of fluid dynamics which made it possible to detail the velocity and temperature fields, the gas flow rates in the plasma region, and also determine the main temperature zones affecting the hydrogen reduction process.
Keywords: RF arc discharge, reduction of volatile chlorides, simulation of gas-dynamic
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Transport properties of thermal plasma containing fluoro-nitrile (C4F7N)-based gas mixtures
Narayanan V. R. T.1, Rümpler Ch.2, Gnybida M.1, Slavíček P.3
1Eaton European Innovation Center, Bořivojova 2380, 252 63 Roztoky, Czech Republic
2Eaton Industries GmbH, Hein-Moeller-Strasse 7-11, 53115 Bonn, Germany
3Department of Physical Chemistry, University of Chemistry and Technology, Technická 5, 166 28 Prague, Czech Republic
Gas mixtures containing fluoro-nitriles C4F7N or fluoro-ketones C5F10O as minority components (<20%) have been identified as promising alternatives to SF6 in medium voltage gas-insulated switchgear (GIS) applications, because of their low Global Warming Potential together with their dielectric strength values being comparable to SF6. The buffer gases in such fluoro-nitrile or fluoro-ketone based gas mixtures are usually N2, O2, CO2, or air. In this contribution, we provide calculation results of transport properties, assuming local thermodynamic equilibrium (LTE), of thermal plasma containing following gas mixtures: C4F7N-CO2 and C4F7N-CO2-O2. The modifications in the thermodynamic and transport properties upon the addition of oxygen to the C4F7N-CO2 mixtures in the temperature range 300 K-30 kK at 1 bar are provided and discussed. These properties have been utilized to calculate the plasma temperature profile for a free-burning arc in a companion paper.
Keywords: Fluoro-nitrile, thermal plasma, transport properties, SF6 alternative
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Development of two-temperature mathematical model of processes in discharge chamber of multi-chamber arrester operating in conditions of mountain areas
Frolov V.1, Ivanov D.1, Sivaev A.2, Chusov A.2
1Peter the Great St. Petersburg Polytechnic University, Polytechnicheskaya, 29, 195251, St. Petersburg, Russia
2Streamer Electric AG, Nevsky Prospect, 147, 191024, St. Petersburg, Russia
This article is devoted to a development of a mathematical model of plasma processes in a discharge chamber of a multi-chamber arrester operating under reduced pressure. The results obtained using this model will make it possible to develop recommendations on modifying the design of multi-chamber arresters for operation in conditions of mountain areas. A composition, thermodynamic and transport properties of plasma for the two-temperature model were calculated on the basis of the data on the materials of the discharge chamber and on the basis of the experiments performed earlier. The paper presents the results of calculations i.e. distributions of discharge voltage and electrical conductivity on time at various pressures. A comparison of obtained results was carried out.
Keywords: 2T model, simulation, pulse arc discharge, multi-chamber arrester
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Arc Behaviours in the HV SF6 Gas-blast interrupter
Averyanova S., Tonkonogov E.
Institute of Energy and Transport System, Peter the Great St. Petersburg Polytechnic University, 29, Polytechnicheskaya st., St. Petersburg, 195251, Russia
A comprehension of the dielectric strength recovery processes during the interruption of short-circuit currents in the high-voltage SF6 gas-blast circuit breakers is necessary for their modernisation in order to increase the rated voltage and short circuit breaking current per one break. This paper presents numerical results of the turbulence effects on the interruption ability in the SF6 extinguishing arc chamber.
Keywords: dielectric strength recovery, turbulence, nozzle geometry, SF6 circuit breaker
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Radiative properties and numerical modeling of C4F7N-CO2 thermal plasma
Gnybida M.1, Rümpler Ch.2, Narayanan V. R. T.1
1Eaton European Innovation Center, Bořivojova 2380, 252 63 Roztoky, Czech Republic
2Eaton Industries GmbH, Hein-Moeller-Strasse 7-11, 53115 Bonn, Germany
C4F7 and C4F7N-CO2 mixtures are considered as alternatives to SF6 for use in medium voltage gas insulated switchgear applications (GIS), due to the low global warming potential and good dielectric properties of C4F7N. Current work is focused on the calculation of radiative properties (absorption coefficients) of C4F7N-CO2 thermal plasma and computational fluid dynamics (CFD) simulations of free burning C4F7N-CO2 arcs that are stabilized by natural convection. Absorption coefficients of C4F7N-CO2 plasma used in the CFD model are derived from spectral absorption coefficients by Planck averaging. An optimization procedure has been applied to find the optimal number of spectral bands as well as spectral band interval boundaries. Radiation and flow model results for C4F
Keywords: radiation, thermal plasma, gas insulated switchgear, SF6 alternative
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Experimental assessment of PTFE post-arc ablation
Babou Y., Corfdir P., Suetterlin R.-P.
Corporate Research, ABB Switzerland Ltd., Segelhofstrasse 1K, CH-5405 Baden-Dättwil, Switzerland
The study addresses the post arc ablation (PAA) of PTFE (Polytetrafluoroethylene) material after being stressed by high current arcs. Arcs were generated in ambient air applying AC or DC current profiles to reach energy input in the range 7-22 kJ. The characterization has been performed essentially based on standard optical measurement techniques. The shadowgraph technique enabled us to show that the PAA flow is composed by a significant amount of carbonaceous soots lasting for several dozens of milliseconds after current interruption. The pyrometry technique allowed to estimate the soots temperature in the range 1400-2200 K.
Keywords: post arc ablation, pyrometry, shadowgraphy
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Plasma pecularities of arc discharge between carbon-copper electrodes
Veklich A., Fesenko S., Boretskij V.
Taras Shevchenko National University of Kyiv, 64/13, Volodymyrska str., Kyiv, Ukraine
The experimental investigations of plasma parameters of electric arc discharge between composite carbon-copper electrodes are carried out by optical emission spectroscopy. It was shown, that arc channel width of electric arc between C-Cu composite electrodes tends to be wider in comparison with those between one-component copper electrodes. The experimentally obtained radial profiles of electron density in plasma channel of investigated arc discharges confirm such conclusion.
Keywords: Plasma, electron density, carbon-copper composite
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Rotating gliding arc: innovative source for VOC remediation
Čech J.1, Prokeš L.1, Zemánek L.1, Dostál L.2, Šimek D.2, Valenta J.2, Žebrák R.3, Zápotocký L.3, Sťahel P.1
1CEPLANT, Faculty of Science, Masaryk University, Kotlarska 2, 611 37 Brno, Czech Republic
2Faculty of Electrical Engineering and Communication, Brno University of Technology, Technicka 12, 616 00 Brno, Czech Republic
3DEKONTA a.s., Dretovice 109, Stehelceves, Czech Republic
The large-scale plasma treatment of waste gas in industrial or municipal conditions requires high efficiency of plasma conversion process at high processing speed, i.e., large volumetric flow. The integration of the plasma unit into existing systems puts demands on the pipe-system compatibility and minimal pressure drop due to adoption of plasma processing step. These conditions are met at the innovative rotating electrode gliding arc plasma unit described in this article. The system consists of propeller-shaped high voltage electrode inside grounded metallic tube. The design of HV electrode eliminates the pressure drop inside the air system, contrary the plasma unit itself is capable of driving the waste gas at volumetric flow up to 300 m3/hr for 20 cm pipe diameter. In the article the first results on pilot study of waste air treatment will be given for selected volatile organic compounds together with basic characteristic of the plasma unit used.
Keywords: gliding arc, rotating electrode, waste gas, VOC decomposition, plasma diagnostics
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Influence of copper vapours in SF6 plasma
Freton P.1, Gonzalez J-J.1, Harry Solo A.1, Reichert F.2, Petchanka A.2
1Laplace, UMR 5213 CNRS-UPS-INP, Université Paul Sabatier 118 rte de Narbonne, bat3R2, 31062 Toulouse Cedex France
2Siemens AG, E T HP CB PLM RD B PB, Nonnendammallee 104, 13629 Berlin, Germany
In this study a theoretical approach allows estimating the ablation mass flux of copper from a corrected Hertz-Knudsen flux. The influence of the copper vapours coming from the anode electrode to an SF6 plasma is studied in a simplified 2D configuration. Depending on the plasma pressure an ablation or a diffusion state is considered. The amount of copper versus time is presented. An RMS current I=10 kA is applied leading at t=10 ms to an amount of copper equal to 0.55 mg. The vapours change the plasma properties mainly the electrical conductivity and radiation and so the plasma behaviour. At time t=5 ms the electrode erosion leads to a copper plasma. This simple case shows the necessity to well consider the copper erosion in plasma modelling as in High Voltage Circuit Breaker (HVCB) where higher current are considered.
Keywords: Copper ablation, High Voltage Circuit Breaker, Electric arc
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Impact of the Metal Evaporation Rate in Vacuum Interrupters on Vapour Expansion and Deposition
Geisler A. E., Wenzel N.
Siemens AG, Corporate Technology, Research in Energy and Electronics, 91050, Erlangen, Germany
The emission of contact material into vacuum after switching operation of a vacuum interrupter is crucial for the metallisation of the ceramic surfaces. This work focuses on the simulation of various regimes of metal vapour pressure using an extended version of an existing DSMC code that now allows the visualisation of the interaction types and locations during the vapour expansion. The model was applied to a typical vacuum interrupter geometry at different current levels between 3 A and 100 kA. The simulations show that in the low current case the likelihood for a particle hitting a ceramic surface can be more than a factor of 5 higher than in the high current case. An explanation of this observation will be given by analysing the interaction history of the respective particles.
Keywords: vacuum interrupter, DSMC method, vapour deposition, insulator coating, vacuum arc
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Post-arc characteristics of high-current arcs in vacuum circuit-breakers
Wenzel N.1, Haas W.2
1Siemens AG, Corporate Technology, Research in Energy and Electronics, 91050 Erlangen, Germany
2Retired employee of Siemens AG, Zentralabteilung Forschung und Entwicklung, 91050 Erlangen, Germany
The post-arc (PA) characteristics of vacuum arcs in transverse magnetic field contacts are studied for short-circuit currents of up to 123 kA peak and transient recovery voltages below 875 V. The measured PA currents are interpreted in terms of an Electric Resistance Model and the models of Andrews-Varey, Langmuir-Child, and Slepian-Schmelzle. Whereas in the late PA period, the calculations do not agree well with the measurements, the PA behavior is well described in the early period after current-zero. It is concluded that the PA discharge is amplified by ionization of metal vapor particles in the boundary sheath due to electron impact.
Keywords: vacuum arc, vacuum circuit-breaker, transient recovery voltage, post-arc current, boundary sheath, transverse magnetic field contact
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Determining the Time Constant of Arcs at Arbitrary Current Levels
Bort L. S. J., Schultz T., Franck C. M.
High Voltage Laboratory, ETH Zurich, Physikstrasse 3, 8092, Zurich, Switzerland
For the development and optimization of gas circuit breakers and switchgear, a detailed understanding of the arc related processes is of great importance. Ideally, analytical or numerical models with predicitive capability can be found and used during the design process preceding costly and time-consuming experiments.
In the present contribution, we report on a novel measurement and evaluation technique to determine the thermal arc time constant ("thermal inertia") that is commonly used in simple black-box models to describe the arc's dynamical properties. The method is introduced and applied to example arcs under varying blow gas conditions in air.
Keywords: switching arc, gas circuit breakers, black-box model, arc time constant
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Generation of silver nanoparticles by the pin-hole dc plasma source with and without gas bubbling
Kozáková Z., Krčma F., Čechová L., Simić S., Doskočil L.
Faculty of Chemistry, Brno University of Technology, Purkyňova 118, 612 00 Brno, Czech Republic
Silver nanoparticles were produced using the pin-hole discharge generated by dc non-pulsing high voltage directly in silver nitrate solutions. Sodium nitrate was alternatively added to increase solution conductivity and decrease input energy for the discharge breakdown. Argon or oxygen was bubbled through the discharge region. Comparative experiments were evaluated by UV-VIS spectrometry. Formation of silver nanoparticles with the average size of 100 nm was confirmed by SEM/EDS analysis.
Keywords: plasma in liquids, pin-hole discharges, silver nanoparticles, silver nitrate, gas bubbling, SEM/EDS analysis
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Performance evaluation method considering shock wave in nozzle for high-voltage circuit breaker
Terada M.1,3, Urai H.1, Nishimura T.2, Yokomizu Y.3
1Research & Development Group, Hitachi, Ltd., 7-1-1, Oomika-cho, Hitachi-shi, Ibaraki-ken, 319-1292, Japan
2Energy Business Unit, Hitachi, Ltd., 1-1-1, Kokubu-cho, Hitachi-shi, Ibaraki-ken, 316-8501, Japan
3Department of Electrical Engineering, Nagoya University, Chikusa-ku, Furo-cho, Nagoya-shi, Aichi-ken, 464-8603, Japan
Interrupting-performance indexes that reflect the physical properties of gas flow are proposed for a breaker terminal fault of a high-voltage circuit breaker. A method of evaluating the shock wave and flow velocity was developed that uses a theoretical equation of supersonic flow which takes into account the nozzle’s shape and stagnation pressure. The predicted flow velocities and positions at which the shock wave forms have strong correlations with the test results.
Keywords: supersonic flow, shock wave, flow velocity, circuit breaker
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Calculation of OPGW strands melting due to DC arc discharge simulating high-energy lightning strike
Iwata M., Nakano T., Kotari M., Ohtaka T., Goda Y.
Central Research Institute of Electric Power Industry (CRIEPI), 2-6-1 Nagasaka, Yokosuka-shi, Kanagawa-ken 240-0196, Japan
Metal strands of OPGWs (composite fiber-optic ground wires) installed in overhead power transmission lines are sometimes melted and broken when struck by high-energy lightning. This paper presents the calculation results regarding OPGW strands melting behavior when struck by DC arcs simulating high-energy lightning. The calculations revealed that the melted volume of the strand was 26% of the strand volume before the arc test, i.e. the rate of the non-melted volume of the strand was 74%. On the other hand, the residual tensile strength of the melted strand was 69% of the other non-melted strands after DC arc test. These results suggest there is a strong correlation between the calculated non-melted volume of the strand and the measured residual tensile strength of the melted strand.
Keywords: ground wire, strand melting, DC arc, lightning, power transmission line
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From switching arcs to ball lightning to curing cancer
Lowke J. J.
CSIRO Manufacturing, PO Box 218, Lindfield NSW 2070, Sydney, Australia
Previous modelling of switching has been through calculation of reductions in temperature of the arc at "current zero". "Enthalpy density" as a function of temperature is found to be an important property. New calculations now include an account of non-equilibrium electron density as a function of time through current zero and it is found that electron attachment rates, which are very large for SF6, could be a dominant property. Modelling discharges is having other successes, for example in explaining "ball lightning" observations inside of houses and aircraft, which suddenly appear, usually at glass windows. Discharge modelling suggests these observations might be explained by the production of "singlet delta" metastable molecules of oxygen in electrical discharges in air. If metastable densities are sufficient, electrons can be produced from the detachment of negative ions to produce radiation and explain ball lightning. An exciting new development is that plasmas from electric corona in air have been found to reduce the size of cancer tumours. These excited oxygen molecules have also been proposed as having a role in this remarkable interchange between classical electrical engineering and medical science.
Keywords: switching arcs, current zero, SF6, ball lightning, cancer
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Arc modeling in industrial applications
Rümpler Ch.1, Chechare R.2, Zacharias A.1
1Eaton Industries GmbH, Hein-Moeller-Strasse 7-11, 53115 Bonn, Germany
2Eaton India Innovation Center, Magarpatta SEZ Tower B6, Pune, India-411013
Simulation methods are routinely applied in the design and development process of power distribution devices. Arcing phenomena that occur during switching operations or fault events are modeled to optimize device performance and gain deeper insights into the behavior that testing cannot easily provide. In this contribution, some applications are presented in detail. The first example describes the distribution of debris that is generated inside a molded case circuit breaker (MCCB) during short-circuit interruption. A model is used to analyze the debris transport and to derive a solution to address issues caused by the debris. Second application example is a cooling device for hot plasma gases vented by circuit breakers. A model driven design process helps to define the device dimensions to achieve a safe temperature level of the exhaust gases. The third example deals with short-circuit behavior of a hollow core high voltage surge arrester, comparing model and experimental results.
Keywords: arc interruption modeling, molded case circuit breaker, debris transport, blow--out cooling, surge arrester
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State of art and challenges for the calculation of radiative and transport properties of thermal plasmas in HVCB
Cressault Y.1, Teulet Ph.1, Baumann X.1, Vanhulle G.1, Kabbaj N.1, Reichert F.2, Petchanka A.2
1Laboratoire Plasma et Conversion d'Energie, Universite de Toulouse, CNRS, UPS, INPT, 118 route de Narbonne, F-31062 Toulouse, France
2SIEMENS AG, Nonnendammallee 104, Berlin, 13629, Germany
This paper is focused on the state-of-the-art and challenges concerning the thermophysical properties of thermal plasmas used in numerical modelling devoted to high voltage circuit breakers. For Local Thermodynamic Equilibrium (LTE) and Non-Local Thermodynamic (NLTE) and/or Chemical Equilibrium (NLCE) plasmas, the methods used to calculate the composition, thermodynamic, transport and radiative properties are presented. A review of these last data is proposed and some comparisons are given for illustrations.
Keywords: HVCB, chemical composition, transport coefficients, radiative properties, NLTE
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