High Voltage Technology
Focus on High Voltage Technology, Focus on Discipline Development
“High Voltage” is the world’s first English academic journal focusing on the latest research progress in the field of high voltage technology, aiming to build an international, high-level academic exchange platform for voltage and lead the development of the discipline. The journal covers four major areas: electrical insulation, discharge and plasma, strong field effects, and high voltage engineering. Since its inception, it has published 6 issues with 43 articles, and has been indexed by IET Inspec and E-SCI databases.
Recently, the editor will organize selected articles based on the research directions of the papers. This issue introduces selected papers on discharge, plasma, and pulse power for your reading and reference.
Title: Influence of Electrode Spacing and Gas Pressure on Parameters of a Runaway Electron Beam Generating During the Nanosecond Breakdown in SF6 and Nitrogen
Authors: Victor F. Tarasenko, Cheng Zhang, Andrey V. Kozyrev, Dmitry A. Sorokin, Xingmin Hou, Natalya S. Semeniuk, Alexander G. Burachenko, Ping Yan, Vasily Yu. Kozhevnikov, Evgenii Kh. Baksht, Mikhail I. Lomaev, and Tao Shao
Publication Date: 2017 Issue 02 Full Text View
This study deals with experimental and theoretical simulation data showing the influence of electrode spacing and gas pressure on parameters of a supershort avalanche electron beam (SAEB) formed in SF6 and nitrogen at different rise times and amplitudes of a voltage pulse. Using GIN-55-01, VPG-30-200, and SLEP-150M pulsers, tubular cathodes with a diameter of 6 mm, as well as gaps of 3, 5, and 8 mm, it was shown that the SAEB current amplitude can both increase and decrease depending on electrode spacing, waveform, rise time of the voltage pulse, as well as the pressure of SF6 and nitrogen. It was established as a result of simulation that maximal voltage across the gap during the process of generation of runaway electrons and the thickness of an anode foil have a major effect on the SAEB current pulse amplitude.
Title:Subnanosecond High-Voltage Breakdown Initiated in High-Pressure Nitrogen by a Runaway Electron Beam
Authors: Alexander G. Burachenko, Victor F. Tarasenko and Evgenii Kh. Baksht
Publication Date: 2017 Issue 02 Full Text View
This study reports on subnanosecond breakdowns initiated on high pressure nitrogen by a runaway electron beam in an inhomogeneous electric field. It is shown that a diffuse discharge with a duration of ≥1 ns is formed in the gas diode. Data are reported for the first time on collector measurements of a supershort avalanche electron beam downstream of an anode foil at a nitrogen pressure of 0.5–1.2 MPa. The beam pulse width at these pressures is ∼90 ps. At a nitrogen pressure of 1.2 MPa, the number of electrons with an energy >70 keV recorded by the collector is 4 × 106/cm2.
Title:Nanosecond Pulse Discharge Based Nitrogen Oxides Treatment Using Different Electrode Configurations
Authors: Sankarsan Mohapatro, Srikanth Allamsetty, Apeksha Madhukar and Nikhil Kumar Sharma
Publication Date: 2017 Issue 02 Full Text View
Nowadays, the intensity of air pollution, due to industries and automobiles, has been increasing continuously. Nitrogen oxides (NOX) are one of the most harmful pollutants, which are released from both automobile and stationary diesel engines. They essentially need to be removed from the exhaust using after-treatment systems. However, the energy required to remove these pollutants is one of the major considerations in selecting the technology for pollutant removal from diesel engine exhaust. A study has been carried out on the non-thermal plasma-based NOX removal technique using various combinations of power supply units and electrode configurations. Three different electrode configurations are tested, in which two are cylindrical electrodes with diameters 3 and 5 mm, and the other one is a square electrode with a diagonal of 5 mm. A comparison is made between the results with two different pulse power supply units, PS-I: high-voltage direct current test set based and PS-II: DC–DC converter based. The square electrode with PS-II has been found to be the optimal combination, which has removed 85% of NOX from the exhaust at an energy density of 55.5 J/L, when the initial NOX concentration in the exhaust is 388 ppm.
Title:NOX Abatement from Filtered Diesel Engine Exhaust Using Battery-Powered High-Voltage Pulse Power Supply
Authors: Sankarsan Mohapatro and Srikanth Allamsetty
Publication Date: 2017 Issue 02 Full Text View
The dielectric barrier discharge-based non-thermal plasma technique is one of the most prominent techniques which give peerless results in controlling the concentration of NOX. However, when it comes to the automobile diesel engine, availability of high-voltage pulse power supply is the major constraint. In this study, battery-powered high-voltage pulse power supply for NO treatment has been proposed. Two types of electrodes: rod type and rod with helical spring type are studied for the treatment of exhaust. Cascaded plasma-adsorbent technique has also been used to enhance NOX removal efficiency. Experiments have been conducted with two different gas flow rates, i.e. 4 L and 6 L/min at laboratory level and have got significant results toward removal of NOX. When the exhaust has been treated with plasma alone, the reactor with rod-type electrode has shown 85% NOX removal efficiency at a specific energy (SE) of 283 J/L with a flow rate of 4 L/min. When the plasma reactor is cascaded with the adsorbent reactor, both adsorbents: 13x molecular sieve (MS13x) and activated alumina are able to remove 100% of NOX with the proposed power supply at a lesser SE.
Title:Optical Characteristics of UV–VUV Lamps on the Electronic-Vibrational Transitions of the Hydroxyl Radical Pumped by a Nanosecond Capacitive Discharge
Authors: Alexandr Shuaibov and Roksolana Gritzak
Publication Date: 2017 Issue 02 Full Text View
This paper presents the results of a study of UV and VUV low-pressure lamp pumped by nanosecond capacitive discharge. This lamp works on the mixtures of helium and argon with water vapor (H2O) or ‘heavy’ water (D2O). At the capacitive low-pressure lamp emission spectra are mainly narrow band 308 nm OH (A–X) and large band in the VUV spectral range: 140~200 nm OH (C, B, A). Found, that the increasing the partial pressure of H2O and D2O (>130~150 Pa) led to a decrease in the intensity of VUV radiation of hydroxyl radicals. In the transition from He/H2O mixture to He/D2O mixture, the optimal pressure of helium is decreased. Reduced partial pressure of argon led to increased intensity of radiation of hydroxyl in the VUV range. The study of emission characteristics of OD* – lamps on a mixture of He/D2O and the OH* – lamps on a mixture of He/H2O showed that the intensity of the bands OD (X, C, A) is 1.5 times larger than the intensity of the bands OH (X, C, A). The maximum absolute intensity of UV–VUV radiation of the lamp (at a frequency of 1 000 Hz) reached 1 W.
Title:Runaway Electrons During Subnanosecond Breakdowns in High-Pressure Gases
Authors: Victor F. Tarasenko, Mikhail I. Lomaev, Dmitry V. Beloplotov and Dmitry A. Sorokin
Publication Date: 2016 Issue 04 Full Text View
The parameters of runaway electrons produced in nanosecond high-voltage discharges in different gases (air, nitrogen, sulphur hexafluoride, krypton, argon, methane, neon, hydrogen, helium) at atmospheric and higher pressure were studied. An optical analysis was also performed to investigate the ionisation dynamics in diffuse discharges in nitrogen and nitrogen-containing mixtures. At breakdown of a point-to-plane gap by nanosecond (≃2 ns) high-voltage (≃200 kV) pulses of negative voltage polarity and gas pressure above 0.1 MPa, a supershort avalanche electron beam (SAEB) was detected by a collector behind the flat anode. For pressure >0.1 MPa of nitrogen and other gases it is shown that the maximum pressure for SAEB registration decreases with increasing the voltage pulse rise time. Therefore, to detect a SAEB at atmospheric and higher gas pressure, one should use voltage pulses with an amplitude of hundred kilovolts and rise time of ∼1 ns and shorter. The experimental research in the dynamics of optical radiation from the discharge plasma shows that the breakdown in which runaway electrons are produced develops as an ionisation wave.
Title:Numerical Study on Propagation Mechanism and Bio-Medicine Applications of Plasma Jet
Authors: He Cheng, Xin Liu, Xinpei Lu and Dawei Liu
Publication Date: 2016 Issue 02 Full Text View
In this study, the propagation mechanism of plasma jet and some bio-medical applications are investigated by two-dimensional numerical model. The key equations of plasma physics and chemistry related with plasma jet are firstly introduced. The simulation results suggest that the sheath forms near the dielectric tube inner surface, which results in the plasma channel to shrink in the radial direction inside the dielectric tube. The photoionisation of air species plays a crucial role in the transition from the localised discharge to streamer. The Penning ionisation increases the electric conductivity of the plasma channel and facilitates the formation of ring-shaped plasma bullet. For the plasma jet in the open air, electron-impact dissociation of H2O, electron neutralisation of H2O+, as well as dissociation of H2O by O(1D) are found to be the main reactions to produce OH. For micro plasma jet, the higher ignition voltage as the tube diameter decreased is attributed to the decreasing pre-avalanche electron density inside the tube. The simulation of plasma treatment of bacteria biofilm indicates that the mean free path of charged species in µm scale permitted the plasma to penetrate into the cavity of the biofilm, and the structure of the biofilm results in the non-uniform distribution of ROS and RNS. The simulation of plasma treatment of cells immersed in liquid suggests that the HO2 generated by plasma aqueous species is the only way for superoxide to penetrate cell membrane and damage cytosolic fumarase B.
Title:Formation Mechanism of Streamer Discharges in Liquids: A Review
Authors: Anbang Sun, Chao Huo and Jie Zhuang
Publication Date: 2016 Issue 02 Full Text View
Streamer discharges in liquids have received lots of attention with respect to their considerable applications in various disciplines. Much effort has been spent to understand the basis of streamer ignition and propagation in dielectric liquids, but a comprehensive mechanism is far from conclusive. In this review, based on an introduction to the streamer physics and experimentally observed characteristics in various liquids, the authors emphasise on the current status of streamer discharge ignition mechanisms and present their understanding for each theory.
Title:Comparison Between Electropositive and Electronegative Cold Atmospheric-Pressure Plasmas: A Modelling Study
Authors: Ding Xin Liu, Jia Feng Li, Ai Jun Yang, Xiao Hua Wang, Ming Zhe Rong and Michael G. Kong
Publication Date: 2016 Issue 02 Full Text View
Cold atmospheric-pressure He+ N2 and He + O2 plasmas are chosen as the representatives for electropositive and electronegative plasmas, of which the discharge characteristics are studied and then compared to each other by fluid models. As the increase of the impurity (N2 or O2) fraction from 0 to 10%, for He + N2 plasmas the electron density and ion density increase, the spatiotemporal distributions of electron density, ion density, electron temperature and electron generation rate change a little. On contrast, for He + O2 plasmas the electron density decreases, the ion density first increases and then decreases, the electron temperature increases in the bulk region, but decreases in the sheath region, and the plasmas transform from γ mode to α mode as the significant change of electron generation rate distributions. Larger electric field is needed in the bulk region to sustain the electronegative plasma, so the electrical characteristics of He + O2 plasmas transform from capacitive to resistive with increasing O2 fraction. Meanwhile, the ion-coupling power increases dramatically, which can be estimated by a formula based on the electronegativity. A new criterion for determining the sheath boundary, |∇E| = 5 kV/cm2, is put forward, which is found suitable for both the electropositive and electronegative plasmas.
Title:Similarity of Gas Discharge in Low-Pressure Argon Gaps Between Two Plane-Parallel Electrodes
Authors: Yangyang Fu, Shuo Yang, Xiaobing Zou, Haiyun Luo and Xinxin Wang
Publication Date: 2016 Issue 02 Full Text View
The similarity of gas discharge in low-pressure argon gaps between two plane-parallel electrodes was investigated by experiments, numerical simulations and theoretical analysis. It was found by the experiments that the breakdown voltages depend not only on the product of gas pressure and gap length, but also on the aspect ratio of the gap, i.e. Ub=f(pd, d/r). It was theoretically proved that Ub= f(pd, d/r) is also a special case, the non-uniform electric field between plane-parallel electrodes, of similarity theorem of gas discharge. It was found by the experiments that there exist similar glow discharges only in two gaps with a limited scaled-down factor k. By theoretical analysis, it was explained that the forbidden processes such as the stepwise ionisation and the inelastic collision of the second kind violate the similarity of discharge as k increases, which was verified by the numerical simulations of the discharges with or without these two forbidden processes taken into account.
Title:Dynamics of Ionisation Wave Propagation in an Applied External Electric Field
Authors: Yang Xia, Dongping Liu, Hamidreza Ghomi, Wenchun Wang, Zhenhua Bi, Longfei Ji, Xueyang Wang, Zhihua Qi and Bin Li
Publication Date: 2016 Issue 02 Full Text View
This study presents spatio-temporal development of the ionisation waves (IWs) along one dielectric tube with an extra alternating electric field. A pulsed direct current power supply is used for generating the IWs, and another alternating current power supply is used for altering the distribution of electric fields along the dielectric tube. The measurements show that the propagation velocity and density of IWs are strongly affected by the external electric field. The direct relation between external electric field and the velocity of the IWs is demonstrated. Further analysis indicates that the external electric field can be utilised to control the propagation of the IWs, resulting in a change of their density and velocity.
Title:Influence of Field Emission on Microwave Microdischarges
Authors: Dmitry Levko and Laxminarayan L. Raja
Publication Date: 2016 Issue 01 Full Text View
An instability in the stable operation of microdischarges sustained at microwave frequencies is investigated by a self-consistent one-dimensional particle-in-cell Monte Carlo collisions model. The instability is caused by the field electron emission from electrodes and is triggered by the high electric fields at the sheaths in a dense microplasma. For an operating frequency of 9 GHz, and electrode gap of 60 µm, the field emission (FE) is not active at the breakdown voltage. However, once a stable dense plasma is produced post-breakdown, a strong sheath results in an electrode electric fields that exceed the threshold for FE causing a runaway in the electron generation in the plasma.
Methods for Recording the Time Profile of Single Ultrashort Pulses of Electron Beams and Discharge Currents in Real-Time Mode
Authors: Victor F. Tarasenko and Dmitry V. Rybka
Publication Date: 2016 Issue 01 Full Text View
The collectors for measuring the time profile of a current pulse of the runaway electron beam that are generated under atmospheric pressure are described. An analysis of changes in pulse shape depending on the bandwidth of the registration path with a temporal resolution of up to 20 ps was performed. It is shown that the electron beam detected behind small-diameter diaphragms has a complex structure, which depends on the parameters of the gas diode. There is a design of the current shunts with a temporal resolution of up to 100 ps in this study. Measurement techniques of voltage pulses with subnanosecond and nanosecond duration are briefly described.
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