High Voltage AC Power Research Articles

Cancer radiotherapy with mini neutron/gamma-ray generators

Recent advancements in negative hydrogen (H-) or negative deuterium (D-) ion source technology as well as the commercial availability of high-frequency AC high-voltage power supplies have enabled the development of mini neutron/gamma-ray generators using low-energy nuclear reactions. These generators can provide a useful flux of high-energy neutrons or gamma photons in either pulsed or continuous operations. With the new mini generator, intraoperative radiotherapy as well as treatment of tumors in the brain, skin, breast, salivary gland, pancreas, liver, and kidney can be performed using external or internal neutron/gamma-ray beams. The new radiotherapy system is very compact and requires very low power for operation, enabling its location inside an operation room of a hospital or clinical facility.

Influence of Applied Discharge Voltage and Gas Flow Rate on Nickel Plasma Jet Parameters Diagnosed by Optical Emission Spectroscopic Technique

Abstract: In this work, we measure the plasma parameters by using an AC high-voltage power supply that generates a non-thermal plasma jet system at atmospheric pressure. A nickel (Ni) metal strip, with dimensions of 1.5 × 10 cm2, was connected to the anode electrode of the AC power supply. This nickel strip was immersed in a flask with a small amount of distilled water positioned below the plasma plume nozzle. Optical emission spectroscopy (OES) was used to diagnose the plasma system at different argon gas flow rates (1-5 L/min) and varying applied voltage values (11-15 kV). It is significant to know the processes accompanying plasma generation to measure their parameters which include the electron temperature (Te), electron number density (ne) of the plasma, Debye length (λD), and plasma frequency (fp). Our results showed an increase in the intensity of spectral lines with the increase in applied discharge voltage (11-15 kV). The maximum peak for ArI was observed at a wavelength of 811.531 nm, and the maximum peaks for nickel (Ni) were observed at wavelengths of 285.21 and 519.70 nm. Also, the results indicated a gradual increase in electron temperature (Te) and electron density (ne) values at the applied voltage of 0.403-0.468 eV. Likewise, the electron density (ne) was in the range of (11.486-13.851) × 1017 cm-3. Keywords: Atmospheric plasma jet, Nickel (Ni) plasma parameters, Electron temperature, Spectroscopic optical emission (OES).

AI & Physics-Based Bad Command/Data Detection in Large Power Electronics Systems: Multi-Port Autonomous Reconfigurable Solar Power Plant (MARS)

Detection of bad data from measurement sensors and bad commands from control centers need to be carried out to avoid instabilities within large power electronics systems. Towards the same, in this paper, model and data driven methods are proposed to identify anomalies in measured data and commands received by large power electronics systems. The large power electronics system considered in this paper is a multi-port autonomous reconfigurable solar power plant (MARS), which consists of photovoltaic (PV) and energy storage systems (ESSs) that connect to high-voltage direct current (HVdc) system and transmission ac power grid. The proposed algorithms in the MARS power plant to detect bad data from measurements and bad commands from control centers are evaluated in simulations and hardware-in-the-loop (HIL) tests. It has been observed that the proposed algorithms are able to detect bad measurements and commands in all the use cases evaluated.

Electrical environment can be altered at 1 km distances from high voltage power lines.

High voltage powerlines emit electrical charges into the atmosphere which can then attach to aerosols. This space charge above ground can be measured directly using ion spectrometers or indirectly through perturbations of the Earth’s potential gradient using field mills. Several publications are reviewed to find evidence of aerosol charging at a distance from power lines. Field measurements of charge state near to high voltage power lines selected due to their high emissions of ions measured a small positive enhancement of electrical charge on aerosols at distances greater than 300 m, corresponding to a transit time of up to 400 s A quasi one-dimensional model of ion-aerosol interactions from a high voltage powerlines found that the addition of new ions to an aerosol population will result in those ions transferring charge to the aerosol which would then remain the dominant carrier of charge several hundred meters downwind. 10-min PG measurements from a fixed site measuring in 2008 compared measurements when the site was downwind of a 275 kV powerline to times with no wind and found evidence of space charge overhead through greater fields and variability at distances over 800 m These studies combined show evidence that the electrical environment near to power lines can be altered beyond 1 km from AC high voltage power lines, with excess charges likely to be concentrated on aerosol.

Dry Reforming of Methane Using a Swirl-Induced Plasma Discharge Reactor

This study reports the dry reforming of methane (DRM) using non-thermal plasma in a swirl-induced point-plane electrode discharge reactor to produce syngas. This reactor geometry facilitates better mixing of the reactant gases in the plasma region, thus increasing the residence time and conversion of the reactants. The effect of varying flow rates and compositions of CO2/CH4 (v%/v%) on conversion was studied. A high-voltage AC power input of 50 W and 70 W at a frequency of 19 kHz was provided. The voltage–current characteristics with respect to time were studied. The results show that with an increase in the flow rate of the gas mixture from 0.5 to 2 LPM the conversion of both CO2 and CH4 decreases, while an increase in the concentration of CO2 or CH4 (from 25 to 75%) increases the conversion of the respective reactant. The products, viz. syngas (CO and H2), C2 hydrocarbons, and solid carbon, were characterized and quantified. The maximum total conversion of 44% was obtained for a CO2:CH4 ratio of 25:75 (v%/v%) at a flow rate of 0.5 LPM. The solid carbon collected from the reactor walls was analyzed, and it was found to be 89.9% pure with traces of oxygen functionality. The increase in flow rate decreased the specific energy input, which eventually resulted in lowering the energy cost.

Relay Protection Method of High Voltage Transmission Line Based on Time-frequency Analysis

Since China entered the era of high-voltage AC and DC hybrid power grids, many high-voltage transmission lines have been successfully constructed. Due to the high voltage and long transmission distance of high-voltage transmission lines, once a fault occurs, it will cause serious losses. The research on the relay protection method of high-voltage transmission lines based on time-frequency analysis is proposed, which has important contribution value to ensure the stable development of the power grid. The fault signal of the high-voltage transmission line is extracted based on time-frequency analysis. The fault transient component of a high-voltage transmission line is detected by decomposing the fault signal characteristics. The phase correlation protection based on the fault transient component is realized to realize the relay protection of the high voltage power transmission line. The simulation results show that the accuracy of the proposed method is 100%, which verifies the reliability of this method.

Study on Ecological Environmental Impact Assessment Index System of UHV AC Transmission and Transformation Engineering-A Case Study of 1000kv UHV Transmission and Transformation Engineering from Zhangbei to Xiongan

Ultra-high voltage (UHV) power grid is a new transmission and transformation technology, which has the advantages of large transmission capacity, long transmission distance, low line loss, saving land resources and obvious economic benefits. Taking the Zhangbei-xiongan 1000kv AC high voltage power transmission and transformation project as an example, this paper constructs the eco-environmental index system of the UHV transmission and transformation project by using the pressure-state-response model, and constructs a set of 18 indexes eco-environmental index system, it mainly includes three aspects: the eco-environmental pressure index caused by the construction behavior in different construction stages of power transmission and transformation projects, and the eco-environmental state index given by on-the-spot investigation and study of projects, based on the construction unit on the ecological environment impact management response measures given indicators. The index system provides a basis for comprehensive and systematic evaluation of the impact of power transmission and distribution projects on the ecological environment, and finally draws the corresponding project construction evaluation conclusions. In this paper, the eco-environmental impact assessment index system of power transmission and transformation engineering has certain universality, and it has certain reference and guiding significance for the ecological environment evaluation of power transmission and transformation engineering.

Degradation of Basic Red 46 dye from color wastewater using cold atmospheric plasma

"Provide an abstract of 50 to 150 words. The abstract should briefly describe the objectives of the research, the results achieved, and the major conclusions. You should give special emphasis to the novelty of your work. The abstract should not contain any undefined abbreviations references. Also avoid introductory remarks, details of the method (e.g., the method has been used for many decades successfully) or listing your results."Contamination of groundwater with colored and toxic wastewater causes many environmental problems and has adverse effects on human health. In this study decolorization of textile dye, Basic Red 46, were studied using advanced oxidation processes (AOPs) in a non-thermal plasma reactor. The reactor is based on pin-to-water high-voltage corona discharge by using a high voltage AC power source and air flow. The rate of the dye removal for 100 ml of this solution was investigated. The results showed that the corona discharge exhibited 85 % of degradation efficiency for 50 mg/l of basic Red 46 within 30 min of treatment time was achieved.

Analysis for metal sheath corrosion rate in AC high voltage power cable

Reliable power transmission requires the safe operation of high-voltage cable. A number of high-voltage cable failures caused by aluminium sheath corrosion has been reported these years. However, neither discussion on factors influencing corrosion rate nor specification describing corrosion inhibiting method has been presented. Thus, it is crucial to address the research gap in evaluating corrosion rate of aluminium sheath in various corrosive environments. Here, the effect of chlorides on aluminium sheath corrosion is analyzed. Using scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS), the corroded surface is investigated. Titration experiment is performed to quantify the chlorides content in buffer layer of cable. Polarization curves are employed to analyze the corrosion rate of aluminium sheath in different chlorides content environment. Surface analysis result shows that chlorine-rich phase can be observed on the corroded surface. Titration experiment result reveals that buffer layer used in high voltage cable is one of the sources of chlorides content which varies from 0.7 to 4.2 wt%. Finally, polarization curve shows that when chloride content increases from 0.6 to 1.8 wt%, the pitting potential left shifts from −0.689 to −0.742 V. The corrosion resistance of aluminium sheath deteriorates significantly with the increase of chlorides content.

High Voltage DC Auto-Transformer Traction Power Supply for Braking Energy Utilization, Rail Potential, and Stray Current Mitigation

For urban rail transit, high-voltage ac power is generally transmitted from the main substation to the traction substation (TS), which employs isolated diode–rectifiers to feed the dc traction power supply system. The train current feeds back to the negative cubicle of TS through the running rail, which is not totally isolated from the Earth. However, the traditional traction power supply (TTPS) shows limitations on braking energy-wasting, high rail potential, stray current, and so on. Thus, a high-voltage dc autotransformer (DCAT) traction power supply (HDATPS) is proposed in this article. Both configurations and principles of three typical HDATPSs are analyzed, which mainly consists of the dc main substation, the dc TS, and the DCAT substation. Then, through modeling of HDATPS and TTPS, the comparisons on braking energy utilization, rail potential, and stray current mitigation are discussed in detail. Finally, the simulation model and experimental platform of HDATPS are built, respectively, and the theoretical analysis is verified with the simulation and experimental results.

Simulated experiments for removal of odorous gases by wire-mesh electrode dielectric barrier discharge

The emission of odorous gases from various industrial processes such as factories and wastewater treatment, in addition to emissions from landfills and livestock, has become a public concern because of their negative effect on air quality and human health. This study presents a technology based on dielectric barrier discharge (DBD) of wire-mesh type with a high-voltage electric wire as the electrode. This system was used to experimentally assess the removal efficiency of odorous gases. The plasma system consists of a wire electrode with a mesh-type configuration, a small blower (1.6 N m3/min, compressed air) for the plasma discharge or to supply cooling gas, and an AC high-voltage power supply. The plasma system offers the advantages of low power consumption and a large discharge area for ozone production. The wire-mesh electrode DBD comprises 64 discharge nodes, and the large amount of ozone generated from these nodes is used to oxidize odorous gases. Under optimized conditions, ozone is stably generated at the rate of 5.1 g/h for a specific input energy of 3.7 J/L. The ozone and odorous compounds (H2S: 4.5 ppm, CH3SH: 6.7 ppm, NH3: 3 ppm, outlet concentration) are injected into the main blower (20 N m3/min, compressed air). Finally, the experiments designed to simulate the removal of odorous gases confirmed that 99% of odorous compounds were removed using the wire-mesh electrode DBD. The cost-effectiveness and scalability of this system make it highly suitable for use in industrial environments where odorous gases are produced.

The Influence of Increasing Argon Gas Flow Rate on Plasma Parameters and their Diagnostics by Optical Emission Spectroscopy (OES)

In this research, the plasma parameters were determined each of electron temperature (Te), electron density (ne), plasma frequency (fp), Debye length (λD). The plasma jet operates with argon gas at atmospheric pressure. It is equipped with an alternating AC high voltage power supply of 12 kilovolts and a frequency of 20 kilohertz. Plasma parameters were calculated from the emission spectrum using an optical emission spectrometer (OES) which captured the spectrum resulting from the plasma at various flow rates of argon gas from 0.5 to 5 L/min. Several peaks of argon gas (ArI) and nitrogen gas (N2) were appeared, where the results showed that the highest peak of argon gas was at 763.51 nm for the fifth flow of argon gas. The results indicated the electron temperature (Te) decrease with increased flow rate and ranged (1.296–0.645) ev, while the electron density (ne) increased with flow rate and ranged were (4.054-5.068x1017) cm-3, respectively. In contrast an increase in the intensity of spectral lines was observed.

Decomposition of hexane and benzene by dielectric barrier discharge plasma and reaction temperature: Comparison of performance of DC nano-second pulsed power supply and AC high voltage power supply

The VOC decomposition performance of a dielectric barrier discharge plasma powered by a DC nano-second pulsed power system was compared with that of an AC high voltage power system. Benzene and hexane were selected as a representative aromatic VOC and a chain-structured VOC, respectively, and the decomposition of each VOC was conducted at the same applied voltage in both systems. The energy of electrons released from the plasma was analyzed, and the ozone production ability was evaluated under a constant applied voltage at different temperatures. Compared with AC high voltage system, the DC nano-second pulsed power system had about 32 times, 26 times, and 30 times better performances for ozone production yield, benzene decomposition yield, and hexane decomposition yield, respectively. For benzene decomposition, the ring cleavage reaction was constant at all reaction temperatures. On the other hand, the mineralization of hexane was largely improved by higher temperatures, because the dehydrogenation reaction was accelerated. Consequently, benzene decomposition was easier than hexane decomposition at the same energy.

Enhancement of Lettuce Growth by PAW Spray Gliding Arc Plasma Generator

The effect of non-thermal air plasma on green oak lettuce farming has been proposed. A gliding arc plasma generator (GAPG) was designed for plasma-activated water (PAW) spray generation. A PAW spray was generated at 8, 10, and 12 kV by a custom-made ac high voltage power supply. Four hydroponic green oak lettuce trays were treated by PAW spray at different conditions for 10 min, three times a day for nine days. The experimental results showed that all the plasma-treated green oak lettuce sprouts had a greater growth rate than the control group. The best condition was found in the PAW spray generated at 8 kV source voltage, which led to the longest average height and width of sprouts of 10.88 ± 0.33 cm and 10.09 ± 0.08 cm, respectively. Moreover, its average dried weight was also significantly greater than that of the control group by 1.69 times. It was found that the concentration of total Kjeldahl nitrogen (TKN), mainly ammonium, was enhanced in every PAW spray condition. However, the highest TKN concentration was found in the 8 kV PAW spray, which was 3.67 times higher than that of the control group. The amount of nitrite (NO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−</sup> ) and nitrate (NO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−</sup> ) in PAW spray was also enhanced but in the opposite trend to TKN concentration. Moreover, the electrical conductivity (EC) and pH levels could be improved by air plasma. It could be confirmed that the plasma treatment could be effectively applied to green oak lettuce farming, and the PAW spray generated by the GAPG could enhance the amount of nitrogenous fertilizer in treated water, which is essential for plant growth stimulation.

Rebuilding and optimization of a high voltage power supply for the additional heating systems of ASDEX Upgrade

One of the unique features of ASDEX Upgrade is the heating power with respect to the size of the plasma. The power at the separatrix divided by the major plasma radius Psep/R representing the normalized heat flux at the divertor is 10 MW/m for 3 s. This is 2/3 of the power expected for a fusion power plant. In order to achieve this goal, the additional heating systems have been strengthened by four new ECRH gyrotrons. For power supply two 30 years old 70 kV / 2.5 MW high voltage AC power controllers have been rebuilt, equipped with a modern digital control system, integrated into the ASDEX Upgrade HV power supply system and optimized for the new task. The paper describes the reconstruction and installation of the power circuits and control system, commissioning, system optimization, operational experiences, present state and findings.

Development of small high-voltage AC power supply for a dielectric barrier discharge plasma actuator.

A dielectric-barrier discharge plasma actuator (DBDPA) is a promising flow control device that can prevent flow separation around an airfoil using electrical discharges. Miniaturizing the DBDPA power supply remains a crucial technological challenge because its size and weight determine the performance of fluid devices equipped with this type of actuator. In this study, we propose a compact high-voltage AC power supply for a DBDPA intended for installation on small airplanes, including unmanned aerial vehicles. The power supply, which consists of a power supply board, a main control board, and a DC/AC converter board, is ∼110g in weight. It can drive a 300-mm long DBDPA without any substantial voltage drop. The power consumption in standby remains below 1W, and the maximum consumption during discharge in burst mode at a burst ratio of 5% is 24W. The power supply uses a lithium-ion battery with a capacity of 1800 mA h, which allows continuous DBDPA operation for ∼1.5 h. An experiment was conducted in a wind tunnel using an airfoil model whose cross-section corresponds to that of an airfoil from a commercial glider airplane. Experimental results reveal that the surface pressure around the airfoil is modified by DBDPA operation, clearly demonstrating the effectiveness of the developed power supply for operating a DBDPA as a flow control device. The size and weight of the proposed power supply can be established as a benchmark to further miniaturize and optimize DBDPA power supplies.

Inactivation of E. coli Using Atmospheric Pressure Plasma Jet with Dry and Wet Argon Discharges.

The acceleration of inactivating viable cells of Escherichia coli (E. coli), by using new direct and indirect innovative methods, is the targeted method of using an atmospheric pressure plasma jet (APPJ) operated by an AC high-voltage power source with variable frequency up to 60 kHz and voltage ranging from 2.5 to 25 kV. Discharges using dry argon (0% O2) discharges and different wet argon discharges using admixtures with O2/Ar ratios ranging from 0.25% to 1.5% were studied. The combined effects of dry and wet argon discharges, direct and indirect exposure using a mesh controller, and hollow magnets were studied to reach a complete bacterial inactivation in short application times. Survival curves showed that the inactivation rate increased as the wettability increased. The application of magnetized non-thermal plasma discharge with a 1.5% wetness ratio causes a fast inactivation rate of microbes on surfaces, and a dramatic decrease of the residual survival of the bacterial ratio due to an increase in the jet width and the enhanced ability of fast transport of the charges to viable cells, especially at the edge of the Petri dish. The membrane damage of E. coli mechanism factors in the activation process by APPJ is discussed.

A Practical Circuit Design for Measuring Output Voltage of High Voltage Frequency-modulated Power Supply

At present, the measurement of output high voltage at intermediate frequency or high frequency of AC power supply relies too much on expensive experimental equipment such as oscilloscope and high-voltage probe. In response to this problem, a design of measuring circuit of the output high voltage at intermediate frequency or high frequency of AC power supply is proposed. In this design, the output high voltage is sampled by setting tap on the high voltage side of the power transformer and using compensation capacitance. The AC voltage obtained by sampling is then converted into DC voltage and measured on gauge outfit. At the end of the article, the experiment shows that the design scheme in this paper has very small error in measurement and can meet the requirements of high voltage experiment for measurement accuracy. High-voltage AC power supply with this circuit can display the measurement of its output high voltage independent of expensive experimental equipment such as oscilloscope and high-voltage probe. Consequently, high-voltage AC power supply with this circuit can help save the cost of experiments and becomes more intelligent and more portable in the experimental situation where researchers are desired for the value of high voltage at intermediate frequency or high frequency output by high-voltage AC power supply.

Study on dielectric barrier discharge in nanostructured electrode materials

In order to conduct dielectric barrier discharge experiments under normal pressure and low voltage (less than 15000V), an ac high-voltage differential power supply based on series-parallel LCC-type(Inductor L and capacitor Cr, Cp are connected in series and parallel structure) resonant converter is designed. The designed power supply prototype has the advantages of small size, light weight and easy operation. The power supply prototype has been tested on loads for many times. Its output repeatability is good and it can continuously output stable sinusoidal ac voltage. At the same time, the prototype also has a strong ability to resist electromagnetic interference. Moreover, the dielectric barrier discharge experiment is carried out using copper electrode with zinc oxide nanowires and copper electrode without zinc oxide nanowires. The experimental results show that the starting voltage of the test group with nanostructures growing on the surface is smaller, about 2500V lower than that of the latter under the same dielectric conditions and discharge spacing. In terms of the discharge phenomenon, the former has a better discharge process consistency, the non-nanostructured electrode discharge is unstable, and the difference in the discharge process is obvious.

Process and kinetics of dye degradation using microplasma and its feasibility in textile effluent detoxification

An array of microplasma discharge was formed on a static aqueous surface by using a high voltage AC power source. The production of hydroxyl radicals (OH) and hydrogen peroxide (H2O2) during the plasma-water-air interaction were quantified and studied their role in the degradation of textile dye i.e. Remazol blue RGB (RB RGB) and as-received textile effluent. Degradation efficiency was evaluated at different applied voltages and initial concentration of dye. The results showed that the microplasma discharge exhibited 99.4 % of degradation efficiency for 50 ppm of RB RGB within 16 min of treatment time and 22.4 % mineralization was achieved. The degradation efficiency increased on increasing the applied input voltage, while it decreased on increasing the initial concentration of dye. Further, the actual textile effluent (received from Tiruppur district, Tamilnadu, India) was treated with this microplasma discharge array and the formation of energetic electrons and free radicals during treatment significantly mineralized the as-received textile effluent with considerable reduction of total organic carbon i.e. 88.6 %. Phytotoxicity studies results reveal that the toxicity of textile effluent was significantly reduced by using the microplasma array discharge.