Characteristics Of Arc Discharge Research Articles

The Influence of Voltage on Gliding Arc Discharge Characteristics, the Composition of Air Plasma, and the Properties of BG-11 Medium

A gliding arc discharge (GAD) plasma device has been developed and tested. Possible applications areas for GAD plasma could be microalgae suspension treatments and the creation of plasma-activated water. To understand its behavior, the influence of the input power on the electrical characteristics of the generated GAD plasma was investigated using an oscilloscope. The waveforms of the voltage and current of GAD plasma are presented. The duration of the discharge time and the evolution of the arc during discharge were determined and investigated. It was revealed that the increase in the output voltage prolonged the duration of the arc discharge. The composition of the air plasma was investigated using a flame-emission spectrometer and acousto-optic emission spectrometer. It was revealed that the main species in the emission spectra of the GAD air plasma were N2, N2+, N+, NO, and O species. Furthermore, the increase in the input power enhanced the ionization degree of the air plasma and increased the intensities of the emission lines associated with N2+, NO, and O species. An increase in the conductivity of the BG-11 medium was observed. Physicochemical analyses of the plasma-activated BG-11 medium indicated an increase in the concentration of nitrite and nitrate ions and hydrogen peroxide with an enhancement of the voltage.

Plasma characteristics of medium voltage AC air arc discharge and its application on arc electrical parameters calculation

Medium voltage (MV) AC air arcs occur frequently in distribution networks. An electric arc can easily cause electrical fires, leading to serious accident consequences. Obtaining the electrical characteristics of arc faults through arc models is a crucial measure to detect and prevent arc faults. The arc electrical characteristics are affected by many factors such as the ambient air pressure, current magnitude, and arc length, and it is difficult to describe it in an analytical form. The widely used conventional black-box arc model reflects the influence of multiple factors on the electrical characteristics of arcs through fitting or empirical formulae. The model ignores the intrinsic physical and chemical processes, and the applicable range of the model is limited. Focusing on this problem, based on the physicochemical processes of the arc in the arcing and post-arcing stages, a relationship between the electrical and plasma characteristics of the MV AC air arc was established. Subsequently, the arc plasma characteristics were determined experimentally, and were applied to the calculation of the arc electric characteristics. Finally, the calculation results of the arc electrical characteristics were verified using the experimental results, providing a basis for related model improvements and applications.

A comparative study on the different energy supply modes for a micro-cathodic arc thruster

The energy supply mode of a micro-cathodic arc thruster (μ-CAT) was adjusted based on the charge and discharge characteristics of the energy storage element, and the cathode discharge characteristics of μ-CAT were studied under different energy supply modes. We applied an electrical method to measure the discharge characteristics of μ-CAT, with an enhanced intensified charge coupled device spectrum detector to measure the plasma parameters of μ-CAT, allowing analysis of the internal logic among thruster plasma parameters, arc discharge characteristics, and thruster energy supply mode. The mechanisms of μ-CAT were analyzed and characteristics of accumulated discharge, energy distribution, and ion velocity distribution of thruster were compared under different energy supply modes to obtain the effect of the energy supply mode on the discharge characteristics of the interelectrode of μ-CAT. The results show that the energy supply mode of μ-CAT affected the ionization characteristics and ionization stability of the micro-cathodic arc thruster, causing a multistage ionization difference in the cathode metal target. This would not only affect the propulsion performance of the thruster, but also affect the change of the number of particles in the cathode region in a single discharge cycle.

Effects of non-electrical parameters on the characteristics of discharge craters and machining performance in short electrical arc milling

During electrical discharge machining (EDM), the process parameters greatly influence the discharge characteristics and machining performance, including electrical and non-electrical parameters. As a new EDM method, short electrical arc milling (SEAM) is plagued by frequent short circuits, poor debris removal, and low energy-transfer efficiency. Therefore, this paper investigated the influence of non-electrical parameters (electrode material, working medium, and electrode rotation) on the crater characteristics, machining efficiency, and electrode wear. The micromorphological characteristics of the workpiece were explored. The results suggested that non-electrical parameters compressed and fractured the plasma channels, thus changing the effect of EDM. The air-tap water medium and electrode rotation promoted debris removal and arc breaking, which prevented the arc from ablating the workpiece. When GH4099 alloy was machined with a copper electrode, the workpiece surface quality and machining efficiency were high, and the thickness of the heat-affected zone was small. This work reveals the characteristics of short electric arc discharge and provided a theoretical basis for the efficient and high-quality machining of difficult-to-cut materials by SEAM.

Plasma diagnosis of tetrahedral amorphous carbon films by filtered cathodic vacuum arc deposition

Filtered cathodic vacuum arc (FCVA) deposition is regarded as an important technique for the synthesis of tetrahedral amorphous carbon (ta-C) films due to its high ionization rate, high deposition rate and effective filtration of macroparticles. Probing the plasma characteristics of arc discharge contributes to understanding the deposition mechanism of ta-C films on a microscopic level. This work focuses on the plasma diagnosis of an FCVA discharge using a Langmuir dual-probe system with a discrete Fourier transform smoothing method. During the ta-C film deposition, the arc current of graphite cathodes and deposition pressure vary from 30 to 90 A and from 0.3 to 0.9 Pa, respectively. The plasma density increases with arc current but decreases with pressure. The carbon plasma density generated by the arc discharge is around the order of 1010 cm−3. The electron temperature varies in the range of 2‒3.5 eV. As the number of cathodic arc sources and the current of the focused magnetic coil increase, the plasma density increases. The ratio of the intensity of the D-Raman peak and G-Raman peak (I D/I G) of the ta-C films increases with increasing plasma density, resulting in a decrease in film hardness. It is indicated that the mechanical properties of ta-C films depend not only on the ion energy but also on the carbon plasma density.

Study on Current-Carrying Tribological Characteristics of C-Cu Sliding Electric Contacts under Different Water Content

Previous studies have often observed that moisture can promote the lubricity and wear resistance of carbon-metal contact pairs in purely mechanical conditions. However, the damage to pantograph carbon strips was found to be aggravated in rainfall conditions, leading to a much lower service life than anticipated. This suggests a novel influence mechanism of water on carbon-copper (C-Cu) contacts during current-carrying friction. In this paper, the influence mechanism of water on the current-carrying friction characteristics of carbon-copper contacts, including friction coefficient, wear loss, electrical contact resistance, and arc discharge characteristics, was studied under different current levels by controlling the water content of carbon sliders. The results show that the variation trend of current-carrying tribological parameters of C-Cu contacts with water content at 60–100 A is significantly different from that at 20–40 A, which is mainly the result of the competition of lubrication, cooling, and obstruction of current transmission by moisture. The abnormal wear of carbon sliders in the water environment occurs when the current is greater than 60 A, and the main reason for the abnormal wear is the intensification of discharge erosion. In addition, micro-crack propagation under high water content is an important factor in the deterioration of carbon strip properties.

Multi-spectral Characteristics of Arc Discharge in Switch Cabinet

The partial discharge (PD) in high voltage switch cabinet might develop into non-penetrating or penetrating arc under extreme conditions, which can lead to insulation failure in severe case. From the optical radiation characteristics of discharge, an optical detection method for abnormal arc was proposed. Multi-spectral characteristics of arc discharge were obtained by the synchronous monitoring of ultraviolet, visible, and infrared optical signals, and the average intensity of light pulse, average light intensity ratio and the light intensity ratio of three bands were analyzed. The results show that the average light pulse intensity of arc discharge and the proportion of three-band light intensity have obvious characteristics and there is a good corresponding relation between the amplitude of discharge light signal and the applied voltage.

Probing ionization characteristics of under-water plasma arc discharge using simultaneous current and voltage versus time measurement in carbon nanoparticle synthesis

Abstract This study investigated the characteristics of plasma ionization that occurs during plasma arc discharge in water using carbon electrodes. The characterization of plasma ionization begins by observing the arc shape using a digital camera associated with voltage oscillation using current and voltage vs. time (I-t and V-t) characteristics. Furthermore, the ionization energy calculation is performed using simultaneous I-t and V-t measurement data. These calculations are then compared to the photon energy from the optical emission spectroscopy (OES). The results from the digital camera indicate four types of arc discharge in terms of shape and intensity related to voltage oscillation. Moreover, the energy calculations show that by using the I-t and V-t methods is possible to measure the plasma ionization detected not only in the range 1–4 eV but also in the outside range, including smaller than 1 eV and greater than 4 eV. These ranges correspond to the emission lines in visible light, infrared, and ultraviolet, respectively. In addition, the I-t and V-t methods can also measure the excitation and recombination energy of the arc discharge plasma ionization. This study reveals the possibility of investigating the characteristics of plasma ionization using simultaneous I-t and V-t measurements, which comprise an easier and more practical method in the diagnostics of carbon nanoparticle synthesis • A novel plasma diagnostic using I-t and V-t measurement were demonstrated as a probing method for ionization of arc discharge. • I-t and V-t measurement measurement reveals voltage oscillation during arc discharge for different states. • The difference in arc intensity and shape is due to the difference in plasma ionization characteristics of arc discharge. • Numerical analysis of single discharge energy is calculated from I-t and V-t data to obtain plasma parameters.

Determination of the voltage drop on a high-current vacuum arc discharge under conditions of a limited cross-section of the plasma flow

The work is devoted to the study of the high-current vacuum arc discharge characteristics under conditions of a limited cross-section of the plasma flow. The experiments were carried out on the IMRI-5 setup with a sinusoidal arc current amplitude of 300–350 kA and a rise time of 500 ns. Aluminum rods with diameters from 3 to 7 mm were used as a cathode. The plasma flow was formed in a channel whose diameter was equal to that of the cathode. The features of the formation of a plasma jet with various configurations of the used plasma gun are described. The electrophysical parameters of the arc discharge are presented. Theoretical estimates of the voltage drop across the high-current arc during the outflow of a plasma flow through holes with a limited diameter are provided.

Disclosure of water roles in gliding arc plasma reforming of methanol for hydrogen production

AbstractTo disclose water roles in plasma reforming of methanol for hydrogen production, gliding arc discharge characteristics, optical emission spectra, and reaction behavior are investigated over a water concentration range of 0–95 mol%. It can be concluded that the varied reaction behavior with water concentration derives from three water roles as a homogeneous catalyst, CO oxidant, and side‐product. The former two roles of water are beneficial for hydrogen production. The side‐product role of water, accompanied by hydrocarbons formation, which is disadvantageous to hydrogen production and can be almost fully inhibited by the homogeneous catalysis of water at above 33 mol% H2O. As an oxidant, water conversion is controlled by the thermodynamic equilibrium at the gas temperature of arc.

Generation of a Nanosecond Pulsed Gliding Arc Discharge With a Repetition Frequency of 300 kHz in an Air Flow at Atmospheric Pressure

Characteristics of a repetitive nanosecond pulsed gliding arc discharge in an air flow at atmospheric pressure driven by a SiC MOSFET inverter power supply are reported for the first time. The gliding arc discharge is produced using two diverging electrodes. The repetition frequency of the pulsed voltage is set from 10 to 300 kHz, and the pulse duration is 500 ns. The propagation distance of the gliding arc discharge almost linearly increases with increasing the repetition frequency of the applied pulsed voltage, resulting in an increase in the discharge reaction area. Dynamics of ignitions and propagation of the gliding arc discharge are revealed with a high-speed camera imaging synchronized with the applied pulsed voltage. The result shows that a shortcut discharge with a different generation mechanism appears. It is found that formation of a shortcut current path between the two legs of the stretched arc discharge occurs, resulting in a new ignited arc discharge. Thus, the pulsed gliding arc discharge can be repeatedly generated without a reignition at the shortest gap between the electrodes. The probability of the occurrence of the shortcut discharge increases as the repetition frequency of the pulsed voltage increases. Additionally, measurements of optical emission spectra of the gliding arc discharge show the presence of excited N2, OH, and NH radicals. The OH emission dominates in the gliding arc discharge with the shortcut events. It can be concluded that the repetition frequency of the applied pulsed voltage becomes the control knob for chemical reactions in future industrial applications.

Combined steam and CO2 reforming of CH4 for syngas production in a gliding arc discharge plasma

To reduce soot formation during the CO2 reforming of CH4 and to optimize the H2/CO ratio of produced syngas, the combination of steam and CO2 reforming of CH4 (SDMR) in a gliding arc discharge (GAD) plasma reactor is investigated. The effect of the addition of steam on gliding arc discharge characteristics, methane reforming performance, and SDMR at varying CH4/CO2 molar ratios are discussed. When the steam-to-carbon (S/C) molar ratio increases from 0 to 2.3, the CH4 conversion and energy conversion efficiency of syngas production (ECEsyngas) increase initially and then decrease, reaching their maximum values (55.6 % and 36 %, respectively) at an S/C ratio of 0.58. The increased number of OH radicals and H atoms generated from H2O in the plasma promotes CH4 dissociation, H2 selectivity and H2 yield. The H2/CO molar ratio increases from 0.76 to 1.1. The addition of steam significantly suppresses the soot formation, allowing the CH4/CO2 molar ratio to range between 1/3 and 3/1 with a carbon balance of >82 % and a broadly adjustable H2/CO ratio (ranging between 0.4 and 3.0). The ECEsyngas decreases while the energy conversion efficiency for fuel production (ECEfuel) increases alongside increasing CH4/CO2 molar ratios. The ECEfuel peaks at 49.3 % at a CH4/CO2 molar ratio of 3/1. Acetic acid is the primary constituent of the resulting liquid product. A possible reaction mechanism of SDMR is also proposed.

Experimental study on gliding discharge mode of rotating gliding arc discharge plasma

Alternating current rotating gliding arc discharge can produce large-scale, wide-range non-equilibrium plasma at atmospheric pressure. In order to investigate the gliding discharge mode, discharge characteristics and Spectral characteristics of AC rotating gliding arc discharge plasma, high speed camera, oscilloscope and spectrometer are used to collect discharge images and electrical signals of rotating gliding arc synchronously. Thus the dynamic behavior of arc and the characteristics of electric signal in the process of rotating gliding arc can be analyzed. The experimental results show that there are two different discharge modes in the rotating gliding arc discharge process, namely the breakdown gliding discharge mode (B-G mode) and the stable gliding discharge mode (A-G mode). The B-G mode is mainly characterized by high-frequency breakdown phenomenon (breakdown-extinguish-breakdown) during the arc gliding process, while the A-G mode is mainly characterized by stable continuous arc sliding. The paper also discusses the working mechanism in which the working parameters influence the gliding arc discharge characteristics. It is shown that the discharge mode and discharge characteristics of arc are the result of the combined action of excitation voltage and gas flow. When the gas flow is large and the excitation voltage is small, the gliding arc is an unstable discharge dominated by the B-G mode. Conversely, when the excitation voltage is large and the gas flow is small, the gliding arc is a stable gliding discharge dominated by the A-G mode. In addition, in B-G mode, the energy consumption is mainly concentrated in the breakdown moment, and the energy release is mainly pulsed. However, when the gliding arc discharge is in A-G mode, the energy dissipation is mainly used to maintain the continuous existence of the arc without extinguishing, and the energy release is stable and continuous. Affected by the gas flow rate and excitation voltage, the breakdown frequency of the B-G mode is greater than that of the A-G mode. Higher repeat breakdown frequency can cause multiple ionization in the process of gliding arc discharge, which produces more active particles. The research conclusions in this paper provide theoretical support for regulating the operating characteristics of the gliding arc discharge. In engineering application, the discharge mode, breakdown frequency and breakdown current of the gliding arc can be adjusted by changing the working parameters to obtain plasma sources with different characteristics.

Effect of current and arc length on characteristics of arc discharge in nonconsumable electrode welding

Effect of current and arc length on characteristics of arc discharge in nonconsumable electrode welding

Влияние тока и длины дуги на характеристики дугового разряда при сварке неплавящимся электродом

Влияние тока и длины дуги на характеристики дугового разряда при сварке неплавящимся электродом

Characteristics of Impulse Arc Discharge in the Circuit of a Powerful Capacitive Energy Storage Device

Within the framework of the engineering approach and channel model of the electric arc, a new variant, impulse air arc discharge between metal (graphite) electrodes of an air double-electrode system (DES), which is part of the heavy-current discharge circuit of a powerful high-voltage capacitive energy storage (CES), was investigated. The amplitude–time parameters (ATPs) formed by the storage device of the current aperiodic pulse in the plasma channel of the air arc discharge corresponded to the slow current C-component of the artificial lighting intended for testing the elements of aircraft for the electrothermal lighting resistance. With respect to the rated ATP of the discharge current, the calculated ratios were obtained, in the plasma channel of the pulse electrical arc in an air DES, for determination of such main characteristics as the equivalent resistance, the released thermal energy, the maximum intensity of the longitudinal electric field, the linear power of thermal losses, the channel current density and the maximum electronic temperature. Distinctive features and general properties of pulse arc discharge in the air DES as compared with heavy-current pulse spark-discharge in similar DES were revealed. The offered ratios allow specifying the energy balance in the CE discharge circuit. The results of the approximate calculations proved the efficiency of the calculated ratios.

Arc discharge and pressure characteristics in pulsed plasma gas of PAW

This paper investigated the arc characteristics in pulsed plasma gas of plasma arc welding using a synchronous image- and electrical signal-acquisition system. The arc sizes (including the arc length L, the arc width on the water-cooling copper plate surface Wa, and the arc width under the nozzle Wc) and arc voltage changed regularly with the plasma gas periodically on/off. And the changing trends of arc sizes were affected by the plasma gas flow rate and the plasma gas switching frequency. The changing scale of arc voltage was proportional to the plasma gas flow rate and was inversely proportional to the plasma gas switching frequency. The average plasma arc welding (PAW) and plasma arc welding with pulsed plasma gas (PPG-PAW) arc voltages were equal when the plasma gas flow rate was the same. The arc pressure also presented cyclical changes during the plasma gas on/off, and the changing scale and the axial mean value were inversely proportional to the plasma gas switching frequency. The periodically oscillating arc and arc pressure would be beneficial to the refinement of grain structure during the welding process.

Beam extraction characteristics of a low-energy, high-current pulsed ion source of a versatile experiment spherical torus neutral beam injector

A neutral beam (NB) ion source aimed to inject a 0.5-MW NB has been developed for Versatile Experiment Spherical Torus (VEST) plasma heating. Beam energy is generally limited to less than ∼20 keV to reduce particle orbit loss and beam shine-through. To meet this power demand, high-current ion beam extraction is important to achieve the required performance of the ion source. In this study, a 0.7-MW ion source was designed, fabricated, assembled, and optimized at the NB test stand in Korea Atomic Energy Research Institute (KAERI) considering the beam power losses in the beamline components. The ion source comprises a multicusped-bucket-type plasma generator and a multislot-triode-type ion accelerator with an extraction area of 12 cm × 46 cm. The characteristics of arc discharge and beam extraction were investigated using hydrogen gas to obtain the optimum operating parameters of the arc power, filament voltage, gas pressure, extraction voltage, and suppression voltage. The ion source was then conditioned and performance tests were primarily completed. Results of the experiments show that the ion source can extract sufficient ion beam power that is than 0.75 MW (50 A/15 keV) with 100-kW arc power. The arc efficiency and beam perveance were estimated to be 0.6 A/kW and 20–25 μP, respectively. Moreover, the design goal of delivering a 0.5-MW NB into the VEST plasma will be achievable based on the optimum operating conditions. This ion source has been installed in the VEST NB injection system at Seoul National University and its commissioning is ongoing.

Study of Liquid Metal Fault Current Limiter for Medium-Voltage DC Power Systems

Fault current limitation is an urgent but challenging technology for medium-voltage dc (MVDC) power systems. For a liquid metal current limiter (LMCL), the arc discharge characteristics often determine its current-limiting properties. The evolving arc in liquid metal is measured by contacting voltage probes, and the properties of the formed dumbbell-like arc column are studied and discussed in detail. It indicates that the total arc voltage almost behaves as a linear function of arc current for an LMCL. Besides, a simplified numerical arc model based on magnetohydrodynamics theory is built and solved by the software FLUENT. It is concluded that the temperature rather than the slightly fluctuant pressure dominates the arc properties, which coincides well with test results to some extent. Finally, a fault current limiter topology including serial LMCLs and parallel resistors is put forward, whose feasibility for MVDC application is discussed on the basis of its current-limiting behaviors.

Numerical study on arc discharge characteristics in double‐ and single‐flow‐type gas circuit breakers

We investigate the effect of exhaust gas flow on the arc discharge characteristics by means of three‐dimensional numerical analyses for double‐ and single‐flow‐type gas circuit breakers (GCBs). The arc voltage of the double‐flow type becomes high compared to the single‐flow type when a cooling gas flows from puffer chamber to the downstream channel. The arc voltage of double‐flow‐type GCB increases by ∼20% during high current of over several kiloamperes. The increase in arc voltage caused by double‐flow exhaust depends mainly on the extension of arc discharge length. The arc conductance per unit length remains unchanged. The arc current decreases below a few kiloamperes, and then the pass of the arc discharge gets much longer and penetrates deep into the tulip contact because of the strong exhaust flow to the tulip contact side in the case of the double‐flow‐type GCB. © 2017 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.