High Voltage Source Research Articles

Generation of Mesoband Signals With Optoelectronic Technique and a Combiner for Intentional Electromagnetic Interference Conducted Tests

In this article, a source for generating conducted intentional electromagnetic interference with a mesoband spectrum is presented in order to perform electromagnetic susceptibility tests on electronic equipment. This high-voltage source is based on different optoelectronic generators, which integrate photoconductive semiconductor switches (PCSSs) operating in a linear switching mode and triggered by a laser pulse. These optoelectronic devices generate a damped sinusoidal signal with a center frequency between 20 and 200 MHz, a Q factor between 11 and 12.4, and a maximum peak-to-peak magnitude of 3.12 kV for a bias voltage of 4 kV. An optoelectronic generator model was designed using Advance Design System (ADS) software, and experimental tests were performed with a measurement bench to compare simulated and measured results. A study on a voltage increase of these generators has been performed and has established the experimental limits of generation in planar technology with low-cost PCSS available on the shelf. The highest peak-to-peak magnitude value obtained is 6.10 kV, it is possible, thanks to the design and manufacture of a power combiner, with ADS and CST Suite Studio software tools, to set up a multiway combination.

Influence of electrostatic field on the interaction of AB5-type alloy LaNi4.4Al0.3Fe0.3 with hydrogen

The effect of the electrostatic field on hydrogen absorption is experimentally studied for the case of AB5-type intermetallic compound LaNi4.4Al0.3Fe0.3 with low equilibrium pressure. Experimental facility contained control and measurement system for PCT-isotherms and a non-conductive polymer vessel immersed in a bath of a thermostat with transformer oil. The test sample with 100 g of the activated alloy powder was used. Electrostatic field was created between a copper tube, which simultaneously served as a hydrogen inlet, connected to a high voltage source and a grounded nickel plate rolled in the form of a cylinder around the outer wall of the vessel. The electrodes were arranged coaxially, the maximum voltage on the internal electrode was 15 kV. The high voltage source also allowed changing the polarity on the internal electrode.It was found that the electrostatic field had no effect on the already established equilibrium in the hydrogen-alloy system at a voltage at the electrode up to 15 kV, regardless of the polarity. However, the process of hydrogen absorption is noticeably slowed down when a voltage of up to 15 kV with negative polarity is applied to the internal electrode, and the effect increases with increasing voltage. At a voltage of 15 kV and the positive polarity of the internal electrode, there was no noticeable effect on the hydrogen absorption process.

Deposition of thin films on glass fiber fabrics by atmospheric pressure plasma jet

Atmospheric pressure plasma jet is conducted to modify commercial glass fiber fabrics using methyltrimethoxysilane (MTMS) as precursor. An alternating current (AC) high voltage source is used to generate argon plasma jet for producing thin films containing silicon and oxygen on the fabric surfaces. The evolution of the prepared films is systematically investigated upon the variations of the precursor flow rate. The smooth surface is transformed into a rough surface with many particles, and the silicon containing functional groups increases with the precursor flow rate, resulting in a hydrophobic surface. Meanwhile, the excessive Si-CH3 functional groups also lead to a dramatic weight loss of the film during high temperature oxidization process. Taking the surface morphology, surface chemical structure and properties into consideration together, the appropriate precursor flow rate condition is found to be 20 ml/h. The optimal sample also presents an eximious ability to resist strong acid corrosion. The above results demonstrate a simple and feasible plasma deposition strategy to modify the surface of flexible materials controllably.

An Apparatus for Measuring the Characteristics of the High-Speed Image Converter Cameras Operating in the Range of Soft X-Rays and Vacuum UV

A pumped vacuum apparatus is described that contains an electron gun with an adjustable high-voltage voltage source, interchangeable metal targets, and flanges to which the object under study is connected. The apparatus is especially designed to measure the spatial and temporal characteristics of high-speed image converter streak cameras that operate in the soft X-ray range. It can be used for research and measurements in the design of soft X-ray photodetectors and their main parts, for example, microprobe detectors, imaging devices, solid-state linear and matrix photodetectors, photoemitters operating in vacuum, etc.

Development of a Test Bench for the Investigation of the Breakdown Voltage of Insulation Materials at Medium Frequency Rectangular Voltages

The increased power and voltage ratings of semiconductors fosters the use in medium voltage components, such as ac–dc converters. With a bipolar medium frequent rectangular (MF RECT) voltage, the converter size can be reduced and the efficiency increased. Possible insulating materials for medium voltage transformers are oil and insulation paper. The breakdown voltage of insulation materials is depending on the frequency and the shape of the voltage curve. Until today, only a few investigations of the breakdown voltage of insulating materials at sinusoidal and RECT voltages up to a few tens of kilohertz have been published. To design and optimize MF transformers at RECT voltages, further investigations are necessary. Therefore, a test bench for measuring the breakdown voltage at RECT voltages in the frequency range between one and ten kilohertz up to several tens of kilovolts is developed. The test bench is inspired by a Marx generator, which is a high voltage source for impulse voltages. By substituting resistances and spark gaps by IGBTs and adding galvanically insulated power sources, a medium frequent bipolar voltage can be generated. The test bench is characterized with respect to slew rate, input power, frequency, and voltage amplitude. Its usability is shown in first breakdown voltage measurements of insulation papers, used for transformer insulation.

Effects of magnetic field on cable sheath corrosion

This article presents the results of research on the effects of utility-frequency magnetic fields on aluminum sheath corrosion of three-phase power cables in a 3 wt% NaCl aqueous solution. Various conditions were considered, including rotating and pulsating magnetic field and connection of the cable to a high-voltage source to research the degradation of aluminum sheath under conditions close to real operation. Influence on surface morphology was evaluated through scanning electron microscopy, energy-dispersive spectroscopy, and X-ray crystallography. Chemical analysis of NaCl solution samples was used to determine how aluminum concentration changes over time, demonstrating the effects of magnetic field. Influence of magnetic field on the evolution of field-gradient force near the sheath was also researched.

Proximative and Contrastive Study of Malachite Green Dye Degradation Using Microplasma Discharge With Postliminary Phytotoxicity Analysis

Array of microplasma jets has been produced in atmospheric conditions using a high-voltage ac power source for the degradation of malachite green (MG) dye in the aqueous solution. The effect of plasma forming gases (air, oxygen, and argon) on the degradation was analyzed by UV-Vis spectrophotometer, and the formation of hydrogen peroxide during plasma–water interaction was quantified. Oxygen plasma produced a relatively high amount of hydrogen peroxide than air and argon, leading to efficient degradation. Oxygen plasma medium exhibited 14.78% and 9.85% higher energy yield than air and argon plasma, respectively. Observation shows that the degradation of MG dye in the aqueous solution follows the first-order kinetics irrespective of plasma forming gases. Phytotoxicity of untreated and oxygen microplasma treated MG dye solution was examined with the germination of tomato seeds. The results illustrate that the toxicity of MG dye was considerably reduced with the microplasma discharge treatment, as it induced 17.4% higher germination percentage than control. The study delineates that oxygen microplasma is an effective, economic and eco-friendly tool for detoxification of huge amount of MG dye in the aqueous medium.

ACTIVATION METHOD OF CLEANING PROCESS GAS

This article presents the results of joint research of ABsalut Ecology LLP with Karstu of industrialelectrochemical aeroion plants B30-500 and AP-21, capable of cleaning technological gas emissions from toxicimpurities SO2 (at least 90%), NOx (at least 80%), CO2 (at least 90%) and dust particles (99.9%); with the return toproduction of part of the burned carbon (in the form of fine soot).It was found that in the discharge zone of the V30-500 and AP-21 installations, the active factors affecting thechemical process are: high voltage of the electric field ; secondary ionization of substances; polarization ofmolecules; high temperature; photoionization; microwave radiation; shock wave. Two processes take placesimultaneously in the reaction zone of the plants: activation and reduction of CO2, CO, NOx, and SO2 oxides toelementary substances in the core of the electronic injector.Reduction of CO2, CO, NOx, and SO2 oxides in the reaction zone proceeds simultaneously by variousmechanisms: catalytic reduction and dissociation. It is established that the catalytic system in the installation is anelectronic injector, which serves as a source of active particles that determine the rate of chemical reactions.Reducing agents CO, NH3 are present in the gas to be treated , and are also formed in the reaction zone of the plant.As a result of the reactions, elementary substances are formed. The speed constants of elementary processes in adischarge strongly depend on the electric field strength, and the speed of individual processes may depend in a nonlinear way on the current density, so by changing these parameters, you can change the selectivity and speed ofrecovery processes in the installation.It is shown that ionization and dissociative processes with the formation of various radicals and ions are feasiblein non-equilibrium weakly ionized plasma. The degree of capture of aerosols and dust increases with a decrease inthe size of dust-like particles, and in dry electric filters, on the contrary, falls to zero.The ways of increasing the efficiency of technological gas treatment plants (geometric parameters of newplants, increasing their productivity, using new high-voltage power sources, flotation and filtration devices, anddispatching control systems) were determined.The efficiency of the gas treatment plant does not decrease when the particle size of the captured aerosolsdecreases, starting from the size of about 5 microns and lower, the cleaning efficiency approaches 100%.The research results are shown as graphs that show the concentration of gas before and after treatment. Thedegree of air purification from dust particles and aerosol impurities ranges from 60% to 99%.

Diamond avalanche diodes for obtaining high-voltage pulse with subnanosecond front edge

In this Letter, we report on demonstrating diamond avalanche diodes for obtaining a high-voltage pulse with a subnanosecond front edge. Under a 2.5 kV driving pulse, the diamond avalanche diodes show a 2.04 kV output and the front edge is 0.894 ns. After repetitive tests, the output voltage wave remains almost the same, indicating good stability. By applying a reverse DC 100 V bias, the front edge shortens to be 0.675 ns, while the rectifier characteristics degrade and the output voltage is limited. Therefore, the reverse bias should be optimized to obtain both the fast front edge and high output voltage. The results show that diamond avalanche diodes have a promising application for high-voltage pulse sources.

Assessment of Potential of the High-Voltage Anodic Plasma Source to Deposit Multilayer Structures Relevant to X-ray Mirror Applications

(1) Background: The high-voltage anodic-plasma (HVAP) coating technique has a series of specificities that are not simultaneously met in other deposition methods. This paper aimed at assessing the potential of HVAP to synthesize quality multilayers for X-ray optics. (2) Methods: Nanolayers of W, Ta, B, and Si were deposited as mono-, bi-, and multilayers onto very smooth glass substrates by HVAP, and their thickness and density were analyzed by X-ray reflectometry. The minimal film thickness needed to obtain continuous nanolayers was also investigated. (3) Results: Nanolayer roughness did not increase with layer thickness, and could be lowered via deposition rate, with values as low as 0.6 for the W nanolayer. Minimal film thickness for continuous films for the studied metals was 4 nm (W), 6 nm (Ta), 2.5 nm (B), and 6 nm (Si). (4) Conclusions: The investigation revealed the range of parameters to be used for obtaining quality nanolayers and multilayers by HVAP. Advantages and possible improvements are discussed. This deposition technique can be tailored for demanding applications such as X-ray mirrors.

A Transformerless DC–DC Modular Multilevel Converter for Hybrid Interconnections in HVDC

In this article, a modular multilevel dc-dc converter philosophy is proposed which can form an effective interlink to exchange power between line commutated converter (LCC) based high voltage direct current (HVdc) link and voltage source converter-based HVdc grid of same or different voltage levels. The converter exhibits symmetric four quadrant operation irrespective of the voltage polarity in the LCC-based HVdc link. In the event of reversal of power flow by reversing the voltage polarity in the LCC-based HVdc link, the power flow direction/magnitude through the interlink can be made to remain unchanged without the need of any extra switching arrangement. The working principle is explained analytically and its operation is validated by simulation as well as experimental results.

Laser Guiding of Three Phase Tesla Coil High Voltage Discharges

Guiding and triggering of discharges from a three phase Tesla coil type 280 kHz AC high voltage source using filaments created by a femtosecond Terawatt laser pulse. Without the laser the discharges were maximum 30 cm long. With the laser straight, guided discharges up to 110 cm length were detected. The discharge length was limited by the voltage amplitude of the Tesla coil. A significant reduction of the breakdown voltage threshold due to the pre-ionization of the air gap by laser pulse filamentation was observed. The lifetime of filaments is measured by using time-resolved fluorescence spectrum, and the lifetime of filaments generated by dual fs laser pulses was doubled due to the re-ionization by the succeeding pulse

Twin loop induction sensor for detection Partial discharge

Partial-discharge is a symptom of high voltage insulation aging, which is a small voltage pulse with high frequency and superposition with high voltage sources that have low frequencies. To find out the existence of this signal, it needs a reliable measurement technique to avoid misinterpretation. This paper presents a technique for measuring partial discharge with an induction method. The sensor used is circular twin loops. The first loop passes through a partial discharge signal, and the second induction receiver produces an induced voltage signal. Various sizes of loop diameters are designed with dimensions 3.2, 4.7, 8.9, and 11.4 cm to look for sensor sensitivity. The performance sensor is analyzed by reading the sensitivity test to the input given with 50-ohm oscilloscope impedance. From the measurement results, the higher the diameter of the sensor loop has good sensitivity.

Study on the reactive power coordinated control in hybrid parallel HVDC system

Hybrid parallel HVDC system adopts line commutated converter high voltage direct current(LCC-HVDC) and voltage source converter high voltage direct current(MMC-HVDC) parallel structure, which combines the advantages of LCC-HVDC and MMC-HVDC. Based on the existing reactive power control of HVDC system, the reactive power coordination control strategy of hybrid parallel HVDC system is innovatively proposed in this paper. Firstly, the reactive power control of LCC-HVDC and MMC-HVDC are studied respectively. And then the voltage stability of LCC-HVDC fed weak AC system is analyzed. Furthermore, a reactive power coordination control strategy between reactive power compensation device of the converter station and MMC-HVDC is proposed. Finally, based on PSCAD/EMTDC simulation platform, a hybrid parallel HVDC simulation system is built. The reactive power coordination control strategy under steady and transient conditions is simulated and analyzed respectively. The analysis results show that the reactive power coordinated control strategy can suppress the voltage fluctuation of converter bus in steady state. At the same time, the reactive power coordinated control strategy can restrain the commutation failure of LCC-HVDC in the fault of receiving power grid and improve its fault recovery ability.

Control unit for a high voltage installation of X-ray microtomograph

A control and indication unit for current operating parameters has been developed for the Spellman XRF-160 high-voltage generator with an output voltage of up to 160 kV, used as part of a high-voltage X-ray microtomograph installation. Thanks to the use of isolating amplifiers in the unit, galvanic separation of the circuits for the formation of control and indication signals with executive circuits of the high-voltage generator is implemented. This makes it possible to virtually eliminate the possibility of the formation of stray ground loops and the flow of dangerous pulsed currents from electrostatic and corona discharges of a high-voltage source in the sensitive circuits of the tomography recording camera and Ethernet communication with the control computer and, as a result, radically increase the reliability of the device. The unit supports the operation of the XRF-160 generator in the modes of stabilization of the output voltage or stabilization of the emission current of the X-ray tube and provides adjustment and indication of the main parameters of the high-voltage installation - the maximum permissible and operating filament current of the cathode, high voltage and emission current of the tube. The unit is assembled in a typical 19-inch case.

A 3D-printed sheathed elutriator for size resolved collection of microparticles and droplets

A low cost, easy-to-manufacture particle classification device for coarse mode, supermicrometer particles and droplets remains important for a variety of industries and environmental measurements, including agricultural sprays, pharmaceutical powders, spray drying processes, precipitation, and dust storms. While optical techniques can typically be used to analyze particle sizes in this range (20 μm–100 μm), there are few instruments available for size-segregated particle collection. Here, we demonstrate that a horizontal, parallel-plate sheathed elutriator can be designed and 3D printed, enabling modest-to-high resolution size segregated particle and droplet collection in the supermicrometer size range. In such elutriators, gravitational settling drives sampled particles vertically down the device (between two plates), while a clean sheath flow drives motion orthogonally; the net result is aerodynamic diameter-specific particle and droplet trajectories. In designing a sheathed elutriator, we develop both an analytical deposition location distribution function, similar to the transfer function of sheath mobility analyzers, as well as a 3D computational fluid dynamics model of a prototype instrument. The prototype is built solely from 3D printed parts (and PVC sheath lines) without any high voltage sources or high power pumps required. The performance of the prototype is tested by examining the deposition location distribution of monodisperse uranine-doped oleic acid droplets in the 26 μm–81 μm size range. Uranine signal intensity was determined using both traditional fluorometric analysis and via yellow-color intensity analysis from a digital camera, with both measurements in good agreement with one another. Overall excellent agreement is observed between the analytical model, computational fluid dynamics simulations, and experimental measurements, demonstrating that inexpensive elutriators provide a means to collect coarse-mode particles in a size selective manner, and further suggesting that they can be designed for aerodynamically monodisperse particle selection.

EXPERIMENTAL INVESTIGATION OF THE CURRENT DISTRIBUTION ON THE SHEET BLANK SURFACE IN LINEAR TOOLS OF MAGNETIC-PULSED ATTRACTION

Purpose. The purpose of the present work consists in the characteristics experimental determination of the pulsed current transverse distribution on the surface of a sheet non-magnetic metal between the point contacts of the power source with different geometry of their connection under operating frequencies variation. Methodology. The measurements were carried out using methods based on the known positions of electromagnetism. The simulating low-voltage equipment was used, as well as high-voltage power sources with a high level of the stored energy. Numerical processing of the measurement results was carried out using standard programs from the «Wolfram Mathematica» package. Results. The space-temporal shapes of the pulsed current density transverse distribution on the surface of the sheet blank were obtained and analyzed. It is established that the degree of transverse current concentration in sheet metal relative to the center of the system in the operating frequency range of ~ 1.8…22 kHz depends very little on its temporal characteristics. It was found that the level of the transverse current concentration in the conditionally allocated band connecting the contacts of connection depends significantly on the ratio of the width of this band and the transverse dimensions of the contact connection. Moreover, the smallest current is concentrated in a strip whose width is much less than the distance between the contacts (£ 11…16 %). Originality. For the first time, the numerical estimates degree of the current transverse concentration are obtained and the dependence of this parameter on the temporal characteristics of the current, as well as on the method of connecting the power source contacts, is established. Practical value. The research results will allow creating the new more efficient linear tools of magnetic-pulsed attraction of sheet metals, based on the force interaction of conductors with unidirectional currents.

Electro-blown spinning driven by cylindrical rotating triboelectric nanogenerator and its applications for fabricating nanofibers

The newly developed electro-spinning based on triboelectric nanogenerator (TENG) is one of the most convenient ways to produce nanofibers, however, it's required to have a high-voltage of no lower than 8000 V, meanwhile, it remains challenging to enhance productivity on push forward the commercialization and with low cost. Herein, we report an innovative electro-blown spinning (EBS) methodology based on a cylindrical rotating (CR) TENG that is fast, efficient, lower high-voltage and cost-effective for the fabrication of polymer nanofiber membranes. The CR-TENG serves both as a high-voltage source and as a receiver, it gave a stabilized elecric output that the short-circuit current (Isc) and transferred charge (ΔQsc) are ~75 μA, ~0.78 μC, and the peak power density (σ) reaches a maximum of ~ 2.23 W/m2. Combined with assisted blowing technology, we have successfully achieved in driven the EBS system by a voltage 6250 V, which has saved more than 21% of high-voltage consumption. In addition, the thickness of produced nanofiber membranes had reached several microns level at manufacturing time within 5 s, then productivity is obviously increased compared with the electro-spinning, and the diameter size of nanofibers has significantly decreased compared to the solution blowing spinning. Moreover, the produced membranes had reached a new level in just a case of a few microns thickness, take the polyethylene oxide (PEO) nanofiber membrane for example, the output Voc, Isc and ΔQsc are nearly 1.6, 1.5, and 1.7 times higher than commercial films.

625 Death Due to Fractal Wood Burning: An Emerging Public Health Problem

Abstract Introduction The art of pyrography, creating designs in wood with a thermal heat source, dates back to prehistory. Risks include cutaneous burns and airway injury. Fractal woodburning is a niche method of pyrography utilizing a high-voltage electrical source to burn branched designs – Lichtenberg patterns – into the surface of wood. While this technique has grown in popularity, the associated risks are not well described. Methods We describe a patient who presented to our burn center after sustaining high-voltage electrical burns from a homemade high-voltage device constructed for fractal woodburning. We also evaluated publicly reported cases of death or injury due to this technique. Results An otherwise healthy 17-year-old male was admitted to our burn center with injuries sustained while making fractal wood art. The patient improvised a high-voltage transformer from a discarded microwave, generating 2000 volts from household current. While using this device to burn Lichtenberg patterns in wood, he contacted the electrodes and sustained full-thickness electrical burns to the neck, chest, and bilateral upper extremities. Bilateral upper extremity fasciotomies were required on admission. Multiple subsequent operative procedures culminated with autografting to the majority of the wounds and ongoing complex reconstruction of the left thumb. In evaluating online news reports, we found 21 unique individuals with death or injury attributed to fractal woodburning. Four sustained substantial injuries, while 17 reportedly died. The first reported incident occurred in July 2016 and the most recent report was from July 2019. Ages ranged from 17 years old to the 60s. Eighteen individuals were younger than 50 years old. All of the mortalities and 3 of the 4 injuries occurred in males. Of the survivors, 3 sustained significant upper extremity injuries and 2 suffered cardiac arrest at the time of injury. The devices used in 4 incidents were microwave transformers and generated 2000 volts. Device characteristics were not identified in the remainder of cases. Conclusions Fractal woodburning is associated with devastating high-voltage electrical injuries and death. Prevention efforts should be focused on the potential risks of this art form. Applicability of Research to Practice News reports likely underestimate the actual incidence of injury and death due to fractal woodburning, however, even this limited data suggests an emerging public health problem requiring further study and public education.

Study of Characteristics of the Cold Atmospheric Plasma Source Based on a Piezo Transformer

In this paper, we study a compact source of low-temperature cold atmospheric plasma based on a piezoelectric transformer used as a high-voltage source. This device can produce a direct piezo-discharge in the atmosphere, a classical dielectric barrier discharge, and a discharge in a noble gas flow. We have estimated the rotational and vibrational temperatures of the N2 ions and the electron temperature in the discharge from the emission spectra for different modes of source operation. When the source operated with loads of two types (metal and liquid loads), the electric field strength distribution near the discharge gap was measured with a probe operating on the basis of the Pockels effect. The possibility of application of this device for electromagnetic field impact on biological objects and plasma-activated media is discussed.