scholarly journals Surface Discharges and Flashover Modelling of Solid Insulators in Gases

Energies ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 591 ◽  
Author(s):  
Mohammed El Amine Slama ◽  
Abderrahmane Beroual ◽  
Abderrahmane (Manu) Haddad
Keyword(s):  
Atmospheric Pressure ◽  
Sulfur Hexafluoride ◽  
Experimental Measurements ◽  
Electrical Equivalent Circuit ◽  
Interface Impedance ◽  
Flashover Voltage ◽  
Surface Discharges ◽  
Insulator Flashover ◽  
Relationship Of ◽  
Air Medium

The aim of this paper is the presentation of an analytical model of insulator flashover and its application for air at atmospheric pressure and pressurized SF6 (Sulfur Hexafluoride). After a review of the main existing models in air and compressed gases, a relationship of flashover voltage based on an electrical equivalent circuit and the thermal properties of the discharge is developed. The model includes the discharge resistance, the insulator impedance and the gas interface impedance. The application of this model to a cylindrical resin-epoxy insulator in air medium and SF6 gas with different pressures gives results close to the experimental measurements.

Viscosity of Dimethyl Sulfoxide + 1,4 Dimethylbenzene System

2008 ◽  
Vol 59 (1) ◽  
pp. 45-48
Author(s):  
Oana Ciocirlan ◽  
Olga Iulian
Keyword(s):  
Free Energy ◽  
Dimethyl Sulfoxide ◽  
Atmospheric Pressure ◽  
Entire Range ◽  
Polynomial Equation ◽  
Energy Of Activation ◽  
Excess Gibbs Free Energy ◽  
Experimental Measurements ◽  
Gibbs Energy Of Activation ◽  
Free Energy Of Activation

This paper reports the viscosities measurements for the binary system dimethyl sulfoxide + 1,4-dimethylbenzene over the entire range of mole fraction at 298.15, 303.15, 313.15 and 323.15 K and atmospheric pressure. The experimental viscosities were correlated with the equations of Grunberg-Nissan, Katti-Chaudhri, Hind, Soliman and McAllister; the adjustable binary parameters have been obtained. The excess Gibbs energy of activation of viscous flow (G*E) has been calculated from the experimental measurements and the results were fitted to Redlich-Kister polynomial equation. The obtained negative excess Gibbs free energy of activation and negative Grunberg-Nissan interaction parameter are discussed in structural and interactional terms.

scholarly journals Surface Discharge Mechanism on Epoxy Resin in Electronegative Gases and Its Application

2020 ◽  
Vol 10 (19) ◽  
pp. 6673
Author(s):  
Herie Park ◽  
Dong-Young Lim ◽  
Sungwoo Bae
Keyword(s):  
Sulfur Hexafluoride ◽  
Design Method ◽  
Surface Discharge ◽  
Uniform Field ◽  
Dielectric Characteristics ◽  
Discharge Mechanism ◽  
Dry Air ◽  
Surface Flashover ◽  
Flashover Voltage ◽  
Insulation Performance

This study presents the surface discharge characteristics of insulating gases, including sulfur hexafluoride (SF6), dry air, and N2, under a non-uniform field. Surface discharge experiments were conducted, with the gas pressure ranging from 0.1 to 0.6 MPa, on samples of epoxy dielectrics under an AC voltage. The experimental results showed that the surface insulation performance significantly improved in insulating gases possessing electronegative gases, such as SF6 and dry air. Surface flashover voltages of SF6 were saturated with an increasing pressure, compared to dry air and N2. The surface discharge mechanism is proposed to explain the improvement and saturation of dielectric characteristics of the electronegative gas in complex dielectric insulations, as well as its influence on the surface flashover voltage. As an application, an insulation design method is discussed with regards to replacing SF6 gas in high-voltage power equipment based on the knowledge of the physics behind gas discharge.

scholarly journals Thermo Physical Properties for Binary Mixture of Dimethylsulfoxide and Isopropylbenzene at Various Temperatures

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Maninder Kumar ◽  
V. K. Rattan
Keyword(s):  
Refractive Index ◽  
Binary Mixture ◽  
Speed Of Sound ◽  
Excess Molar Volume ◽  
Atmospheric Pressure ◽  
Composition Range ◽  
Isentropic Compressibility ◽  
Experimental Measurements ◽  
Kister Equation ◽  
Thermo Physical Properties

Density, refractive index, speed of sound, and viscosity have been measured of binary mixture dimethylsulfoxide (DMSO) + isopropylbenzene (CUMENE) over the whole composition range at 298.15, 303.15, 308.15, and 313.15 K and atmospheric pressure. From these experimental measurements the excess molar volume, deviations in viscosity, molar refractivity, speed of sound, and isentropic compressibility have been calculated. These deviations have been correlated by a polynomial Redlich-Kister equation to derive the coefficients and standard error. The viscosities have furthermore been correlated with two or three parameter models, that is, herric correlation and McAllister model, respectively.

Atmospheric pressure argon surface discharges propagated in long tubes: physical characterization and application to bio-decontamination

2015 ◽  
Vol 48 (46) ◽  
pp. 464003 ◽  
Author(s):  
Zuzana Kovalova ◽  
Magali Leroy ◽  
Carolyn Jacobs ◽  
Michael J Kirkpatrick ◽  
Zdenko Machala ◽  
...  
Keyword(s):  
Atmospheric Pressure ◽  
Physical Characterization ◽  
Surface Discharges

scholarly journals Effect of Ice Shedding on Discharge Characteristics of an Ice-Covered Insulator String during AC Flashover

Energies ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 2440
Author(s):  
Xiangxin Li ◽  
Ming Zhou ◽  
Yazhou Luo ◽  
Gang Wang ◽  
Lin Jia
Keyword(s):  
Leakage Current ◽  
Discharge Characteristics ◽  
Fundamental Component ◽  
Ceramic Insulator ◽  
Flashover Voltage ◽  
Arc Shape ◽  
Surface Discharges ◽  
Ieee Standard ◽  
Ice Shedding ◽  
Indeterminate Variation

Considering the ice shedding phenomena on ice-covered outdoor insulators, this paper conducted the artificial experiments by using a five-unit suspension ceramic insulator string covered with wet-grown ice to investigate the effects of ice shedding on the icing discharge characteristics. According to IEEE Standard 1783/2009, the minimum flashover voltage (VMF), propagation of discharges to flashover and related leakage current (LC) were measured. It was found that VMF after ice shedding can be increased by about 17% as compared with that before ice shedding. The initiation and formation of discharge arcs across ice-free regions caused by ice shedding become difficult, showing an unstable propagating path, indeterminate arc shape and longer arc column. Although VMF under ice shedding conditions is higher than that without ice shedding, the fundamental component, and harmonics show lower amplitudes for the latter case. The ratios of harmonics to the fundamental are well in accordance with discharge characteristics during the flashover for which the ratios show a relatively stable varying tendency in the absence of ice shedding, but show changeable and indeterminate variation under ice shedding conditions. The obtained results are helpful to understand the icing state and its influence on surface discharges for preventing the icing flashovers.

scholarly journals Experimental study on the effect of applying a crossed magnetic field on the insulator flashover behavior in high vacuum

2015 ◽  
Vol 05 (03) ◽  
pp. 1550026
Author(s):  
K. Abu-Elabass
Keyword(s):  
Magnetic Field ◽  
Electric Field ◽  
Transverse Magnetic Field ◽  
High Vacuum ◽  
Transverse Magnetic ◽  
Magnetic Flux Density ◽  
Surface Flashover ◽  
Vacuum Degree ◽  
Flashover Voltage ◽  
Insulator Flashover

In this study, a possible method of reducing the flashover stress is achieved by the effect of an additional magnetic field in the transverse direction on the main applied electric field. The degree of vacuum used in this study was [Formula: see text] Pa. The magnetic flux density B employed in this study extends from [Formula: see text] to [Formula: see text] T. From the results obtained throughout this work, the transverse magnetic field increases the flashover voltage and decreases the leakage current. The effect of the transverse magnetic field on the surface flashover of the dielectric solid in vacuum shows a marked dependence on the material and the thickness of the test specimen, the vacuum degree, the type of electric field (AC or DC) as well as the type of magnetic field (AC or DC).

scholarly journals Study of thermo-acoustical properties of Liquid mixtures of Aqueous solution of Lithium Chloride and Lithium Hydroxide at Different Temperatures

2021 ◽  
Vol 33 (2) ◽  
pp. 5-11
Author(s):  
NEERAJ RATHORE ◽  
◽  
AJAY KUMAR SINGH ◽  
Keyword(s):  
Aqueous Solution ◽  
Lithium Chloride ◽  
Acoustic Impedance ◽  
Atmospheric Pressure ◽  
Adiabatic Compressibility ◽  
Liquid Mixtures ◽  
Lithium Hydroxide ◽  
Experimental Measurements ◽  
Acoustical Properties ◽  
Different Temperatures

Density, viscosity and ultrasonic velocity of the various compositions of liquid mixtures of aqueous solutions of Lithium chloride (LiCl) and Lithium hydroxide (LiOH) have been experimentally measured at 303,308,313 and 318K and at atmospheric pressure. From these experimental measurements the acoustic impedance (Z) and adiabatic compressibility (ad) have been calculated. The variations in these parameters have been correlated to derive the intermolecular interactions taking place between the mixtures of present study.

scholarly journals Study on Insulator Flashover Voltage Gradient Correction Considering Soluble Pollution Constituents

Energies ◽  
2016 ◽  
Vol 9 (11) ◽  
pp. 954 ◽  
Author(s):  
Dongdong Zhang ◽  
Zhijin Zhang ◽  
Xingliang Jiang ◽  
Zhongyi Yang ◽  
Jiayao Zhao ◽  
...  
Keyword(s):  
Voltage Gradient ◽  
Flashover Voltage ◽  
Insulator Flashover ◽  
Gradient Correction
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