High Frequency Voltage Research Articles

High-Voltage FDS of Thermally Aged XLPE Cable and Its Correlation with Physicochemical Properties.

This paper aims to investigate the influence of thermal aging on a crosslinked polyethylene (XLPE) cable, and the relationships between the macroscopical high-voltage dielectric and the microscopical physicochemical properties are also elucidated. To better simulate thermal aging under working condition, the medium-voltage-level cable is subjected to accelerated inner thermal aging for different aging times. Then, high-voltage frequency domain spectroscopy (FDS) (cable sample) and analyses of microscopic physical and chemical properties (sampling from the cable), including Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and elongation at the break (EAB), are conducted at different cable aging stages. The dielectric test results show that after a certain aging time, the high-voltage FDS curves of the cable have layered characteristics, and this phenomenon is more obvious as the aging degree increases. Moreover, the slope and the integral of the high-voltage FDS curves rise with aging time. The mechanism is deduced by the physicochemical results that thermo-oxidative aging results in increasing polar groups and dislocation defects in the crystal region, which leads to the above phenomenon. On the one hand, the appearance of polar groups increases the density of the dipole. On the other hand, the destruction of the crystal region increases the probability and amplitude of dipole reversal. In addition, the breaking of molecular bonds and the increase in the amorphous phase also reduce the rigidity of the XLPE molecular main chain. The above factors lead to obvious delamination and larger dielectric parameters of the thermally aged cable. Finally, according to the experimental results, an on-site diagnosis method of cable insulation thermal aging based on high-voltage FDS is discussed.

Power Supply Analysis and Design for DBD Ozonizer under the Current Zero Crossing and Phase Locking Inductive Control

In order to fill the blank of practical engineering application of inductive control in ozonizer power supply, this paper probes into a scheme of high frequency and high voltage inverter for the control, and analyses operation modes to form a reasonable theoretical result, and introduces a new current zero crossing and phase locking method to adjust the address deviation and ensure that the address pointer directs to the last value of inverter current by changing the sampling period and adjusting the error of practical reference address pointer at each zero crossing point. The results from theoretical derivation, numerical simulation, and power experiment prove that the scheme can suppress the current spike caused by diode reverse recovery and reduce the power loss of switch devices, which is conducive to cost reduction. © 2022 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC.

BEHAVIOR OF THE SQUARE WAVE IN BIOLOGICAL STRUCTURES

This study is to experimentally investigate the behavior of quadratic waves in biological structures. Transcutaneous frequency stimulation was regulated so that the system provided high frequency and low electrical voltage to observe possible changes in deeper layers of the anatomical structure analyzed. Electrodes were positioned from the dermis and probing electrodes were positioned at the subdermal, intradermal, skeletal muscle, periosteum, endosteum, and medulla levels. A function generator connected to a digital oscilloscope produced a square wave of 33 kHz at 10µs pulse speed and voltage of 16 volts DC. A voltage decay was observed as the signal reached deeper layers of different tissues. However, the frequency of 33 kHz remained uniform even at the bone marrow level. This observation opens the way for the application of the square electronic frequency as a stimulus for drug activation.

Initial nucleation of metastable γ-Ga2O3 during sub-millisecond thermal anneals of amorphous Ga2O3

Beta-phase gallium oxide (β-Ga2O3) is a promising semiconductor for high frequency, high temperature, and high voltage applications. In addition to the β-phase, numerous other polymorphs exist and understanding the competition between phases is critical to control practical devices. The phase formation sequence of Ga2O3, starting from amorphous thin films, was determined using lateral-gradient laser spike annealing at peak temperatures of 500–1400 °C on 400 μs to 10 ms timescales, with transformations characterized by optical microscopy, x-ray diffraction, and transmission electron microscopy (TEM). The resulting phase processing map showed the γ-phase, a defect-spinel structure, first nucleating under all annealing times for temperatures from 650 to 800 °C. The cross-sectional TEM at the onset of the γ-phase formation showed nucleation near the film center with no evidence of heterogeneous nucleation at the interfaces. For temperatures above 850 °C, the thermodynamically stable β-phase was observed. For anneals of 1–4 ms and temperatures below 1200 °C, small randomly oriented grains were observed. Large grains were observed for anneals below 1 ms and above 1200 °C, with anneals above 4 ms and 1200 °C resulting in textured films. The formation of the γ-phase prior to β-phase, coupled with the observed grain structure, suggests that the γ-phase is kinetically preferred during thermal annealing of amorphous films, with β-phase subsequently forming by nucleation at higher temperatures. The low surface energy of the γ-phase implied by these results suggests an explanation for the widely observed γ-phase inclusions in β-phase Ga2O3 films grown by a variety of synthesis methods.

The Physical Mechanism of Frequency-Induced Inflection Point for Oil–Paper Insulation Under High-Frequency Square-Wave Voltage

High-frequency (HF) oil-immersed transformers with small size and light weight have been paid wide attention by researchers. Its oil–paper insulation frequently withstands HF over-voltages at frequencies of several kilohertz and above, resulting in the too early failure of oil–paper insulation. In order to investigate the effect of HF on oil–paper insulation, this article investigates the partial discharge (PD) characteristics of oil–paper insulation under HF stress. The experimental results show that a frequency-induced inflection point is existed near 10 kHz and the PD parameters of HF voltages is much higher than that ac voltages. Besides, the theoretical mechanism is expounded to interpret and understand the formation process of frequency-induced inflection points more easily. It can be found that the change in frequency causes the change in the charge decay time constant and the residual charge on the insulating surface, resulting in the formation of the frequency-induced inflection point at HF. These results might contribute to determine the characteristics of PDs between HF voltages and ac voltages. It can provide references for the research and production of HF transformers.

Power Electronic Solution for Dust Emission from Thermal Power Plant

In thermal power stations, flue gases are let to the atmospheric air through the chimney. This exhaust gas contains some toxic elements like Suspended Particle Matter (SPM), SOX, NOX, Mercury etc. It causes air pollution in the atmosphere and affects the human beings and aquatic lives. The allowable limit of this flue gas dust emission to the atmosphere is about 50 mg/m3. In order to separate this dust particle from the flue gas, Electrostatic Precipitators (ESP) are used to collect those unwanted suspended particles before passing them to chimney. ESP requires high efficiency to extract those dust and hence, High-Frequency High Voltage (HFHV) power supply is applied to increase the efficiency of the collecting electrode of the electrostatic precipitator. The HFHV power supply provides a significant reduction in the size and weight of the complete ESP installation.

Modified Charge Transport Model Under High-Frequency Unipolar Square Wave Voltage

As the main insulation material of the power electronic transformer (PET), polyimide (PI) is easy to accumulate space charge under the continuous high-frequency pulse voltage, which will threaten the operation of PET and cause electric field distortion. At present, the microscopic mechanism of charge transport under high-frequency voltage is unclear. Numerical simulation is an effective method to explore the transport characteristics of space charge. The simulation of charge transport under DC voltage is mainly based on the bipolar charge transport (BCT) model. However, the charge transport behaviors under high-frequency pulse voltage cannot be simulated by the traditional models accurately. Given this, based on the BCT model, the High-Frequency Voltage Charge Transport (HFCT) model is proposed, considering nonlinear charge mobility of the polymer and the effect of the frequency. Finally, the space charge and electric field distribution under square pulse wave voltages with different rising times are simulated based on the HVCT model, concluding that the reduction of rising time will promote the accumulation of space charge. In view of this, the HVCT model is expected to optimize the insulation design of PET and provide a reference for the dynamic simulation of space charge.

Electric Field Modelling and Simulation of the High-voltage High-frequency Transformer Insulation Applied for Power Electronics Based on Circuit-field Coupling Analysis

This paper established a transient electric field model of a high-voltage high-frequency (HVHF) transformer based on circuit-field coupling analysis. As the key component of power electronic transformers (PETs), the operating conditions of the HVHF transformer are determined by the converter circuit containing it. To find out the electrical stress withstood by the solid insulation, it is essential to model the transient electric field while considering the circuit model of the converter. The circuit model of the converter and the 3-D transient electric field model based on the finite element method (FEM) are built in ANSYS. The voltage and current waveforms on both primary and secondary sides of the HVHF transformer obtained from the converter model are coupled to the transient electric model as the excitations. Based on the established model, a case study of a 60 kHz HVHF transformer used for the dual active bridge (DAB) converter is investigated, and the electric field characteristics of the insulation are analyzed. The electric field distribution inside and on the surfaces of the insulation is present, and magnitude values of the highest electrical stress inside and on the surfaces of the insulation are identified. The theoretical verification is carried out based on the grid convergence index (GCI) method and it verifies the accuracy of the proposed model. This model could be used to calculate the overvoltage capacity of the HVHF transformers in various power electronics applications and it is an essential step in building the digital twin model of the HVHF transformer.

Multipurpose distributed dielectric-barrier-discharge plasma actuation: Icing sensing, anti-icing, and flow control in one

Icing and stalling on the surfaces of aircraft wings endanger flight safety. The object of this research is a nanosecond pulsed dielectric-barrier-discharge plasma actuation unit with a distributed layout, and the aerodynamic performance of aircraft wing surfaces under icing and stalling conditions is improved by changing the plasma actuation electrical parameters. Actuated under low voltage and frequency, the unit acts as a sensor to judge icing according to the change in electrical parameters. Actuated under high voltage and frequency, the discharge is severe and generates a large amount of heat, giving rise to an anti-icing unit; anti-icing is carried out through distributed-layout plasma actuation, forming modulated ice with evenly spaced distribution, which acts as a vortex generator and lessens the deterioration of aircraft aerodynamic performance under icing conditions. Actuating under high voltage and low frequency enables flow control, delays stalling, and increases lift. The different plasma-actuation functions are realized by connecting multiple units, which offers improved aircraft survivability in complex weather conditions.

RESEARCH OF PHYSICAL PROCESSES IN LAMINATED MAGNETIC CORES OF ELECTRIC MACHINES

The aim of this work is to use fast-moving processes to detect defects in the inter-sheet insulation of laminated magnetic core of electric machines. Violation of the sheet insulation causes increased eddy currents as a result of increased losses and integrated local overheating in the body of the magnetic core. The article develops a mathematical field model of induction distribution in a toroidal toothed magnetic core of an asynchronous motor series 4AA63V4U3 0.37 kW when superimposed on the back of the core of the power winding powered by a high frequency voltage source in the range. An experimental study of losses in the magnetic coret and the distribution of losses on eddy currents and remagnetization (hysteresis).
 When designing an electric machine, its operating characteristics, optimal operating modes, thermal condition and many other factors are calculated using the nominal values ​​of steel parameters, windings and all materials used in the machine. However, these materials do not always have the stated characteristics and quality. For example, during the manufacture and stamping of electrical steel sheets, it is exposed to a significant level of influence, which in some way affects its characteristics. In addition, even if we assume that during the production of all stages of manufacturing the material came flawlessly, the condition and as a result the parameters of materials and EM in general change during operation as a result of accidents or even simple aging and wear.
 Therefore, given these facts, it becomes clear that during planned or unplanned repairs it makes sense to check the condition of materials, insulation, as their condition depends on the allowable loads, temperature, etc. In particular, the state of the magnetic circuit largely determines the temperature around the conductors in the grooves and as a result determines how long the winding will actually last in contrast to the specified service life and rated power at which to use this EM.
 The concept of the state of the magnetic circuit can be divided into the state of electrical steel and the state of its insulation. The first component changes quite poorly during operation and is generally caused by the "aging" of steel if you do not take into account any serious damage as a result of accidents, but it can be damaged during manufacture. But the second component is significantly affected during operation and significantly determines the quality of the magnetic circuit as a whole.

Systematic identification of low voltage-high frequency electrogram zones at sites of left atrial reentrant tachycardia termination

Abstract Funding Acknowledgements Type of funding sources: Private company. Main funding source(s): Abbott Background Localization of the narrow isthmus of conduction of left atrial local and macro reentrant tachycardia (LAMRT) circuits within scar tissue is challenging. (Panel A). Near-field (NF) electrograms are often obscured by and difficult to distinguish from far-field (FF) activation. The peak frequency (PF) associated with bipolar electrograms is a novel parameter which may distinguish between NF and FF signals. (Panel B). However, the potential value of PF for LAMRT ablation has never been evaluated. Purpose 1) To quantify the percentage of LA surface with low voltage (LV) and NF signals. 2) To study the proportion of LAMRT ablation sites which were located within a LV-NF region or in the vicinity of it (<10 mm away). Methods LART bipolar voltage and activation maps were generated with a 16-pole grid catheter (HD-Grid) during tachycardia. (Panels A,B). PF maps were retrospectively computed (Panels C,D). LV zones were defined according to a cutoff <0.3mV. Four different PF cut-off values (>250, >300, >350 and >400 Hz) were assessed in the delineation of overlapping LV-NF regions. (Panel E) Results 16 consecutive patients with 24 LAMRT’s targeted for ablation were prospectively enrolled. 21/24 LAMRT’s were terminated by radiofrequency application. (Panel F). The LV area represented 47.7±14% of the LA surface. The LV-NF area represented 8.2±6.2%, 5.2±5.4%, 3.4±7.4% and 3.3±4.1% of the LA surface by using 250, 300, 350, and 400 Hz PF cutoffs respectively. There were 2.1±1 (range 0-3), 0.9±0.8(range 0-3), 0.5±0.6 (range 0-2) and 0.5±0.6 (range 0-2) LV-NF areas per patient using 250, 300, 350 and 400 Hz PF cutoffs respectively. At the optimal PF cutoff > 250Hz and voltage < 0.3mV, the site of tachycardia termination by radiofrequency application was found inside of a LV-NF region in 13/21 LAMRTs (sensitivity 68.4%), and within 1cm of a LV-NF region in 19/21 LAMRTs (sensitivity 89.5%) respectively. Conclusion 1. Left atrial reentry termination sites by radiofrequency application are often within or nearby LV-NF areas as identified by the PF and voltage analysis of bipolar electrograms. 2. Beyond conventional substrate mapping, the systematic identification of high frequency activity within the low voltage zone holds promise for rapid identification of isthmus conduction critical to LAMRTs.

Experimental research on closed plasma discharge and spectral diagnosis excited by high voltage and high frequency power supply

This paper proposes a design for developing a closed plasma generator based on the low-pressure multilayer dielectric barrier discharge and glow discharge, and the discharge excited by the high-voltage and high-frequency power supply. The closed plasma generator forms the core equipment for the application of closed plasma stealth technology. The traditional plasma stealth experiments are intended for generating the plasma in the vacuum chamber. The discharge experiment has been carried out in two closed discharge chambers with dimensions 8 × 8 × 2 cm3 and 30 × 30 × 2 cm3, using a high-voltage high-frequency power supply. The influence of multiple excitation parameters on the gas discharge has been studied, the emission spectrum data have been measured to obtain the plasma parameter distribution in the cavity, and the factors affecting the plasma parameter distribution in the closed discharge cavity have been analyzed. The amplitude of the discharge current of the multilayer dielectric barrier discharge method has been found negligible, and the range of the plasma parameters is limited. However, by using a nanosecond pulsed glow discharge, the uniformity of plasma distribution has been significantly improved. Further, it is conducive for the adjustment of the plasma parameters corresponding to the cavity.

Real Time Power Control in a High Voltage Power Supply for Dielectric Barrier Discharge Reactors: Implementation Strategy and Load Thermal Analysis

Atmospheric-pressure plasma treatments for industrial and biomedical applications are often performed using Dielectric Barrier Discharge reactors. Dedicated power supplies are needed to provide the high voltage frequency waveforms to operate these nonlinear and time-dependent loads. Moreover, there is a growing technical need for reliable and reproducible treatments, which require the discharge parameters to be actively controlled. In this work, we illustrate a low-cost power supply topology based on a push–pull converter. We perform experimental measurements on two different reactor topologies (surface and volumetric), showing that open loop operation of the power supply leads to a temperature and average power increase over time. The temperature increases by ΔTvol~120 °C and ΔTsup~70 °C, while the power increases by ΔPvol~78% and ΔPsup~60% for the volumetric (40 s) and superficial reactors (120 s), respectively. We discuss how these changes are often unwanted in practical applications. A simplified circuital model of the power supply–reactor system is used to infer the physical relation between the observed reactor thermal behavior and its electrical characteristics. We then show a control strategy for the power supply voltage to ensure constant average power operation of the device based on real-time power measurements on the high voltage side of the power supply and an empirical expression relating the delivered power to the power supply output voltage. These are performed with an Arduino Due microcontroller unit, also used to control the power supply. In a controlled operation the measured power stays within 5% of the reference value for both configurations, reducing the temperature increments to ΔTvol~80 °C and ΔTsup~44 °C, respectively. The obtained results show that the proposed novel control strategy is capable of following the transient temperature behavior, achieving a constant average power operation and subsequently limiting the reactor thermal stress.

Temperature Dependent Morphological and Electro-Optical Characteristics of Dye Doped Cholesteric Liquid Crystal

Cholesteric liquid crystals (CLCs) have gain remarkable attention due to its property of stabilizing the planar (P) and focal conic (FC) states. This paper presents the temperature dependent behavior of cholesteric liquid crystal (CLC) mixed with appropriate amount of dye. The pitch of sample corresponds to visible region (~1 µm) was adjusted by adding appropriate concentration of chiral dopant. The phase transition and morphological behavior was recorded using polarized optical microscope (POM) from planar state to isotropic state by heating the sample using temperature-controller. Experimental results indicated that increase in temperature impacts the morphology of CLC and strongly affects its electro-optical (E-O) properties. Further, POM studies showed that at room temperature dye doped CLC cell has initial transparent state (planar texture) however, when driving voltage was high (~27V) with lower frequency of 1 kHz, P state switched to FC state. On further increasing the temperature, minor distortion was observed in P state in comparison to P state of dye doped CLC cell at room temperature, however, at higher (~ 45˚C) temperature, low driving voltage was required to achieve the stable FC state. Further, FC state was switched to stable P state on applying high frequency (50 kHz) voltage. Afterward, above 45˚C temperature, the textures showed the sustained FC state of dye doped CLC cell with no switching to P state on applying high frequency (50 kHz) voltage. Thus, temperature dependent dye doped CLC cell showed the bi-stability feature upto 45˚C temperature, however, above this temperature showed the fixed FC state.

Analysis and suppression of voltage oscillation at DC circuit breaker terminal in DC fault transient process

High-frequency voltage oscillation occurs at the initial stage of DC short-circuit fault in the modular multilevel converter (MMC)-based high-voltage direct-current systems, which directly threatens the reliable operation of the secondary equipment in DC circuit breakers (DCCBs). Therefore, this paper focusses on the voltage oscillation characteristic at DCCB terminals, considered the stray parameters of connecting lines, the parasitic parameters of main equipment and the impedance of grounding grid, established equivalent circuit models of MMC-HVDC converter station at the initial stage of pole-to-pole and pole-to-ground fault, and obtained the analytical formula for the voltage oscillation frequency. Then, the comparison with the DC short-circuit test data of ±200 kV MMC-HVDC converter station verified the validity of the models and revealed the mechanism of voltage oscillation. Finally, the influence of the parameters of the converter station on the oscillation characteristics was discussed. It was proposed to install the DCCB at the MMC valve's terminal near the DC side, and the oscillation frequency is about 10–60 kHz, which is more than 5 times lower than that at the DC reactor's terminal near the DC pole bus, and the disturbance of oscillation to DCCB was alleviated.

A high voltage capacitance measurement method based on alternating coupled signal injection.

As high voltage pulse power capacitors, ceramic capacitors are widely used in high voltage pulse generators, trigger circuits, laser generators, and other fields. The capacitance of ceramic capacitors is closely related to the direct current (DC) bias voltage. However, the current capacitance measurement methods can only achieve a DC bias of 1 kV, which cannot meet the measurement requirements in high voltage environments. This paper proposes a capacitance measurement method that can accurately measure the capacitance under a DC bias of 3 kV. This method decouples the high DC bias voltage and high frequency alternating small signals and realizes low voltage calibration and high voltage isolation. The experimental results show that the proposed method measures the capacitance under a DC bias of 3 kV with a relative error within ±1%, which makes it possible to accurately quantify the capacitance hysteresis deviation in the process of increasing and decreasing back the voltage.

Научно-методические основы физиолого-гигиенической оценки термической нагрузки среды с учетом использования средств индивидуальной защиты от электрических полей промышленной частоты на высоковольтных объектах

Due to the new technologies and power networks development, the number of extremely high-voltage power frequency sources increases. These sources may affect the human nervous, cardio-vascular systems as well as vision. Maintenance, repair, and adjustment of high-voltage equipment is carried out by the electricotechnical staff. Electrotechnical staff is exposed to power frequency electric field from the switchyards and overhead transmission lines where permissible limit values are exceeded. Human health protection from the harmful power frequency electromagnetic field effects is an actual issue of the occupational safety. Staff safety work must be provided by use of the personal protective equipment from unfavorable and hazard occupational factors. Usual personal protective equipment is the conductive suit, which includes conductive clothes, facescreen, gloves and footwear. Screening property of the personal protective equipment are based on the principle of Faraday cage, which is realized by the conductive materials. These materials and personal protective equipment need to have optimal air permeability and water vapor transmission properties. In accordance with the possible work outdoors, in the warm season especially, electrotechnical staff is exposed not only to the main harmful occupational factor, and climatic environments too, such as air temperature, its movement speed, humidity. Personal protective equipment development requires complex multifactorial assessment with special attention to the human body physical load value, his functional state, metabolic parameters, as well as suit thermal insulation.

Improved Cross-coupling Effect Compensation Method for Sensorless Control of IPMSM With High Frequency Voltage Injection

In this paper, the conventional cross-coupling effect compensation method that uses offline measured cross-coupling factor by current compensation in high frequency pulsating voltage injection based sensorless control is firstly extended for use in high frequency rotating voltage injection based sensorless control by angle compensation. Compared with the current compensation method, the angle compensation method has better dynamic performance as confirmed by experiments. To enable direct angle compensation, a novel method for offline measuring the cross-coupling induced errors is proposed by injecting HF voltages in <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">d</i> -axis and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">q</i> -axis, respectively. The measured errors can be used for online cross-coupling effect angle compensation irrespective of the injected signal that is used for position estimation. Experiments have verified the effectiveness of the proposed methods. In addition, stability and convergence of sensorless operation with the proposed cross-coupling effect compensation methods at highly saturated conditions are also analyzed and experimentally evaluated.

Experimental Low-Speed Performance Evaluation and Comparison of Sensorless Passive Algorithms for SPMSM

Sensorless algorithms for PMSM have achieved an increasing interest in the technical literature. They can be divided into active methods and passive methods. Active methods exploit rotor anisotropy by injecting high voltage frequency signals, whereas passive methods are based on observers. Even if passive methods do not have the drawbacks of active methods – acoustic noise, torque ripple and harmonic distortion - their effectiveness is reduced in the low speed region. For this reason, active methods are usually used at low speed and the motor control switches to passive methods in the high-speed region. Since high frequency injection is associated to many drawbacks, the aim of passive methods is to work at lower speed as possible or, ideally, to be able to start directly the motor. That is particularly true for Surface-Mounted PMSM: since they have a low anisotropy, high frequency injection should be particularly elevate to achieve sufficient signal-to-noise ratio. It is difficult to compare the performance of passive algorithms proposed in the technical literature since experimental tests have been done with different conditions: motors, inverter features, measurements, type of tests, etc. In this paper, five different sensorless passive algorithms for Surface-Mounted PMSM, selected among the most promising algorithms available in the technical literature, are compared, performing the same tests on the same experimental setup, to achieve a fair comparison and establishing the most performing one.

Low-frequency glow discharge (LFGD) plasma treatment enhances maize (Zea mays L.) seed germination, agronomic traits, enzymatic activities, and nutritional properties

BackgroundPlasma technology is an emerging sector in agriculture. The effect of low-frequency glow discharge (LFGD) plasma at medium pressure (10 torr) on maize morpho-physiological and agronomical behavior was investigated in the current studies. The LFGD plasma act as a secondary messenger to improve maize production. This cutting-edge plasma technology can be used in agriculture to boost agronomic possibilities.Materials and methodsMaize seeds were treated with LFGD Ar + Air gas plasma for 30 s, 60 s, 90 s, and 120 s. The gas ratio of Ar + Air was 1:99. Plasma was produced with a high voltage (1–6 kV) and low (3–5 kHz) frequency power supply across the electrodes. The internal pressure was maintained at ~ 10 torrs with a vacuum pump in the plasma chamber. Inside the plasma production chamber, the gas flow rate was maintained at 1 L/min.ResultsEffect of LFGD Ar + Air plasma on seed germination, and growth parameters including, shoot length, root length, fresh weight, dry weight, plant height, stem diameter, and chlorophyll were measured and in comparison with the control the parameter scores increased by 4.89%, 3.18%, 1.77%, 5.53%, 1.90%, 5.16%, 1.90%, 1.98%, respectively. The SEM image of the seeds surface demonstrated remarkable changes caused by plasma treatment. In roots, APX and SOD activities improved by only 0.022% and 0.64%, whereas, in shoots their activities showed a 0.014% and 0.25% increment compared to control. Further, H2O2, soluble protein, and sugar content increased by 0.12%, 0.33%, 2.50% and 1.15%, 1.41%, 2.99%, 1.16% in shoots and roots, respectively, while NO showed no significant changes in plants. Interestingly, notable improvement were found in nutritional properties (protein 0.32%, fat 0.96%, fiber 0.22%, ash 0.31%, grain iron 1.77%, shoots iron 7.61%, and manganese 6.25%), while the moisture content was reduced by 0.93% which might be useful in prolonged seed storage and the long life viability of the seeds. However, zinc (Zn) content in maize seedlings from plasma-treated seeds showed no significant change.ConclusionThe present study revealed that LFGD Ar + Air gas plasma is associated with the elevation of ROS in leaves and roots, which in turn improves the seed germination rate, agronomic traits, growth, enzymatic activity, and nutritional supplement in maize.Graphical