The work is devoted to the study of the characteristics of a low-temperature plasma of a high-frequency (HF) discharge (f=13.56 MHz) ignited between metallic and electrolytic electrodes at atmospheric pressure. Burning of an RF discharge in a diffuse (volumetric) form is observed at the interface between the media between the electrodes. Numerical calculations of the electric field strength and the distribution of the volumetric power density of the Joule heat release before breakdown in a vapor-gas mixture near a metal electrode are presented. The discharge radiation spectrum, plasma composition, and electron density were studied by optical emission spectroscopy. The thermograms of the electrode surface under the conditions of an RF discharge are considered. Keywords: Plasma-liquid systems, high-frequency discharge, electrolytes, numerical methods.

The results of experimental studies and numerical calculations of the parameters of an electric discharge with a liquid (nonmetallic) cathode in air flow at atmospheric pressure are presented. The shapes of plasma structures arising in the interelectrode gap are described. The plasma composition and electron concentration are determined by optical emission spectroscopy, and the temperature of the surface of the electrodes in the discharge burning zone is determined by the infrared thermography method. The current–voltage characteristic (CVC) of the discharge is plotted. The results of numerical calculations of the distributions of the power density of the Joule heat release and the electric field strength near the metal anode are presented. The formation of a vapor–liquid mixture around the part of the metal anode immersed in the electrolyte is described.

The results of experimental studies of the electric discharge of alternating current (f = 50 Hz) in a gas–liquid environment of an electrolyte with bubbles for interelectrode distances of 50–150 mm inside a dielectric tube are presented. The presence of a bubble structure with microdischarges affects the nature of the discharge current and voltage ripples. The frequency spectrum of voltage and current oscillations of the discharge is established using the fast Fourier transform. Based on the analysis of the experimental data, the mechanism for the development of an alternating current electric discharge in a medium with microbubbles is established.

Представлены результаты экспериментальных исследований и численных расчетов параметров электрического разряда с жидким (неметаллическим) катодом в потоке воздуха атмосферного давления. Описаны формы плазменных структур, возникающих в межэлектродном промежутке. С помощью оптической эмиссионной спектроскопии установлены состав плазмы и концентрация электронов. Методом инфракрасной термографии определена температура поверхности электродов в зоне горения разряда. Построена вольт-амперная характеристика разряда. Приведены результаты численных расчетов распределения плотности мощности джоулевого тепловыделения и напряженности электрического поля вблизи металлического анода. Описано образование парожидкостной смеси вокруг погруженной части металлического анода в электролит.

The characteristics and mathematical modeling of the behavior of a low-temperature direct-current electric discharge plasma ignited between an aluminum anode and an electrolytic cathode (3% NaCl solution in purified water) at atmospheric pressure are investigated. The discharge is ignited by immersing the metal anode into the electrolytic cathode. The types and forms of plasma structures generated in the interelectrode gap are considered. The results of high-speed recording of the discharge breakdown and combustion are presented. The electrophysical parameters of the discharge, including pulsations and current/voltage fluctuations are studied. The emission spectroscopy method is used to determine the discharge emission spectrum, plasma composition, electron concentration, and temperature of heavy plasma components. The heat patterns of the surface of liquid nonmetallic and metallic electrodes in the discharge combustion zone are considered. The results of numerical simulation of electric field strength and the initial stage of the discharge are presented.

The work is devoted to the study of the characteristics of a low-temperature plasma of a high-frequency (HF) discharge (f = 13.56 MHz) ignited between metallic and electrolytic electrodes at atmospheric pressure. Burning of an RF discharge in a diffuse (volumetric) form is observed at the interface between the media between the electrodes. Numerical calculations of the electric field strength and the distribution of the volumetric power density of the Joule heat release before breakdown in a vapor-gas mixture near a metal electrode are presented. The discharge radiation spectrum, plasma composition, and electron density were studied by optical emission spectroscopy. The thermograms of the electrode surface under the conditions of an RF discharge are considered.

In this work, we studied an alternating current discharge in a copper sulfate solution (3% and 10%) with a distance l=150 mm between copper electrodes located inside a dielectric tube with an electrolyte at atmospheric pressure. On the basis of the obtained electrical characteristics of the discharge, a pattern of discharge generation was presented: electrolysis -breakdown - development of the discharge. Volt-ampere characteristics have a falling character, volt-second characteristics are of a direct exponential type, ampere-second characteristics are of a reciprocal exponential type. Using the fast Fourier transform, the voltage and current spectra were obtained. In the voltage spectrum, it was revealed that the voltage is little subject to fluctuations. It has been established that peaks corresponding to frequencies of 50, 150, 250, 350 Hz, etc. are observed in the current spectrum. It is revealed that the intermediate frequencies present in the current spectrum and constituting an almost continuous spectrum appear as a result of stochastic discharge-breakdown processes.

Single-phase earth faults are one of the main problem of the distribution electrical networks with voltage 6 - 35 kV with isolated neutral. Single-phase earth fault is one of the reasons decrease of the power quality and the reliability of power supply. The paper presents the theoretical base of the monitoring parameters selection during the single-phase earth fault process and its practical implementation as an installed system at a power substation with a 110/10 kV level voltage. The hardware part of the feeder monitoring system allows implementing the determination of feeder with fault and the phase of this feeder with fault without the need to switch off of the feeders. The software part of the system allows for ongoing monitoring of feeders with built-in alarm and viewing the event archive on the supervisor computer.

The aim of the paper is theoretical and experimental research of processes during the single-phase ground faults in electrical distribution grids of 10/06/35 kV with isolated neutral mode. The mathematical method of rationing is used for the analysis of the spectral composition of currents and voltages increasing the information content of the allocated higher harmonics of current and voltage. The paper show a comparison of the results of spectral analysis with and without taking into account the mathematical rationing obtained on the simulation model. Field experiments have demonstrated the effectiveness of using of the method of mathematical rationing of the higher harmonic components of current and voltage for various types of single-phase ground faults. The results of field experiments provided an opportunity of improving the methodology of yearling detection of single-phase ground faults in electric grids of 6-10-35 kV with an isolated mode of neutral. The conclusion of the research is the possibility of a significantly more accurate selection of the resonant frequencies of the spectrum of currents and voltages obtained by using of the method of mathematical rationing. The possibility of earlier and more precise localization of the feeder with ground fault is shown on the base more precise selection of the resonant frequency currents and voltages.

The problem studied here is important because of the need for an efficient technology for monitoring the state of the wire in a span based on combined software and hardware for analyzing the technical state of the wires in 110 kV overhead electrical transmission lines in order to obtain a comprehensive estimate of the effect of external climatic factors owing to wind and ice loading, as well as the amount of thermal elongation of the wires owing to the effect of current flow. An analysis of the instantaneous state of the wires and their limiting mechanical strength makes it possible to evaluate the effectiveness of measures for preventing accidents and lessening the undersupply of electrical power to final consumers. Visualizing the instantaneous parameters of the wire in a span of an overhead electrical transmission line will make it possible to reduce the time needed to undertake steps to prevent emergencies. The algorithm for monitoring the state of wires in overhead lines is based on information about the existing values of the longitudinal and transverse angles obtained with sensors that are installed directly on the wire in an electrical transmission line.

This article proposes a new approach for welding metals without the use of high-temperature arc plasma, inert gas and without filler wire. A new technological process of welding takes place with the help of an electric discharge in the electrolyte environment. The electrolyte-plasma method of welding metals allows to increase the speed in comparison with the existing market analogues, improving the quality of welding, at the same time: it saves raw materials, reagents, increases productivity. The creation of such a product corresponds to advanced production technologies and can ensure the competitiveness of domestic companies in the scientific and technical information markets and in high-tech industries.

The results of the numerical simulation of the glow discharge between the pin cathode and the electrolytic anode are presented. The electron concentration distribution for the different distances from the anode were calculated. The 2D distribution is calculated for the equipotential lines between the steel cathode and the electrolytic anode. The essentially nonuniform character of the electric field strength distribution along the discharge axis was discovered. The obtained distribution of the electric field strength between the metal cathode and the electrolytic anode is in a good qualitative agreement with the results of the experiments realized in the similar conditions.

Представлены результаты численного расчета модели тлеющего разряда между штыревым катодом и электролитическим анодом. Рассчитаны распределения концентрации электронов для различных расстояний от анода. Приведено двухмерное распределение расчетных эквипотенциальных линий между стальным катодом и электролитическим анодом. Установлен существенно неоднородный характер распределения напряженности электрического поля вдоль оси разряда. Полученное распределение напряженности электрического поля между металлическим катодом и электролитическим анодом находятся в хорошем качественном согласии с результатами экспериментов, проведенных в близких условиях.

The object of this research is radio-frequency electric discharge in electrolyte in the processes of surface treatment of materials. The forms and structures of electric discharge, the results of X-ray structure analysis, metallographic analysis of surface samples before and after treatment are presented in the article.

Results are presented from experimental studies of the shape, structure, and spectral characteristics of an RF capacitive discharge operating between a droplet-jet electrolytic electrode and an electrolytic cell in air at pressures of P = 10 3 –10 5 Pa, as well as of a discharge burning between a copper rod and the surface of non-flow electrolyte at atmospheric pressure. It is found that, at voltages of U ≥ 3500 V, the multichannel discharge burning between the rod and the electrolyte (saturated solution of NaCl in technical water) surface transforms into a torch discharge. Specific features of the burning of a discharge with a droplet electrolytic electrode are investigated. Different forms of discharges burning on the surface of a copper tube and an electrolyte jet are revealed.