143 results on '"Olivier LESAINT"'
Search Results
2. Dielectric relaxation and ionic conduction in 66%Silica/CW229-3/HW229-1 microcomposite polymer
- Author
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Abdelkader, Kahouli, Pascal, Rain, Olivier, Lesaint, and Céline, Rigaud
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- 2015
- Full Text
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3. Conductivity Measurement and Interpretation in Dibenzyltoluene at High Temperature and High Electric Field
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Chencho Dorji, Olivier Lesaint, Rachelle Hanna, and Christophe Pollet
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- 2022
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4. Time-Resolved Non-Linear Electric Field Simulation on Liquid Embedded Substrate
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Chencho Dorji, Rachelle Hanna, and Olivier Lesaint
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- 2022
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5. Contact degradation due to material transfer in MEM switches.
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Alexis Peschot, Christophe Poulain, Frédéric Souchon, Pierre-Louis Charvet, Nelly Bonifaci, and Olivier Lesaint
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- 2012
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6. Prebreakdown and Breakdown Phenomena in HFO Gas Under Impulse Voltage. Part 2: Quasi-Uniform Field
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Simon Soulié, Nelly Bonifaci, Olivier Lesaint, and François Gentils
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Electrical and Electronic Engineering - Published
- 2023
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7. Prebreakdown and Breakdown Phenomena in HFO Gas Under Impulse Voltage. Part 1: Divergent Field
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Simon Soulié, Olivier Lesaint, Nelly Bonifaci, and François Gentils
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Electrical and Electronic Engineering - Published
- 2023
- Full Text
- View/download PDF
8. Dielectric performance of insulating liquids for transformers
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Lars, Lundgaard, Qiang, Liu, Olivier, Lesaint, Stefan, Tenbohlen, Inge, Madshaven, Rainer, Frotscher, Jan, Hajek, Philip, Schmitt, Carl, Wolmarans, Beriz, Bakija, Dejan, Vukovic, Santanu, Singha, Zhongdong, Wang, Attila, Gyore, and G2Elab, HAL
- Subjects
[SPI.NRJ] Engineering Sciences [physics]/Electric power - Abstract
Dielectric liquids, in combination with solids, have been used for insulating power transformers for more than a century. While mineral oils have dominated the market, new liquids with different molecular structures are now in common use. This brochure addresses the dielectric performance of the liquids as used in a transformer - including the potential influence of solid insulation on the behaviour of prebreakdown streamers in the liquid. Topics discussed include how the chemical composition of liquids influences the streamer velocities and breakdown, and how the electric field configuration may govern breakdown modes. The aim of this brochure is to review the dielectric requirements and test standards of dielectric liquids as seen from a transformer designer, to review the behaviour of dielectric liquids.
- Published
- 2021
9. Analysis of Chemical By-products from Partial Discharges in Air
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François Gentils, Nelly Bonifaci, Diana El Khoury, and Olivier Lesaint
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010302 applied physics ,Work (thermodynamics) ,Ozone ,Materials science ,Humidity ,High voltage ,02 engineering and technology ,Plasma ,Dielectric barrier discharge ,021001 nanoscience & nanotechnology ,Fault (power engineering) ,01 natural sciences ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,0103 physical sciences ,Nitrogen oxide ,0210 nano-technology - Abstract
Partial discharges (PDs) are believed to be one of the key factors accelerating high voltage (HV) equipment ageing. The chemical by-products of PDs actively contribute to the modification of insulations surface quality, especially in air medium due to the diversity of its constituents. Although nonthermal plasmas in air have been widely studied, their adaptation to HV systems is still highly complex and prone to controversies. In this work, a typical simulation of a fault leading to PD in air, through a Dielectric Barrier Discharge (DBD) point-to-plane configuration, is performed in order to measure ozone (O 3 ), nitrogen oxide (NO) and dioxide (NO 2 ) by-products gases. The evolution of these species regarding PD duration, PD power and humidity is analyzed. Ozone production rate and dynamics are found to predominate over NO 2 and NO ones. The effect of humidity on gases evolution is found to be indirect, as it mainly affects PD power.
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- 2020
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10. Discharges and Streamers Properties in Dielectric Liquids under Various Temperature
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Joko Muslim, Ngapuli I. Sinisuka, Olivier Lesaint, Rachelle Hanna, and G2Elab, HAL
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Materials science ,synthetic ester ,Perfluoropolyether ,Dibenzyltoluene ,divergent field ,Dielectric ,Impulse (physics) ,Atmospheric temperature range ,Amplitude ,Chemical physics ,Electric field ,dibenzyltoluene ,perfluoropolyether ,partial discharges ,streamers ,Voltage ,[SPI.NRJ] Engineering Sciences [physics]/Electric power - Abstract
This paper presents partial discharges and streamers characterizations on 3 dielectric liquids under variation of wide temperature range, i.e.: aromatic hydrocarbon dibenzyltoluene, synthetic ester and halogenic perfluoropolyether liquids. Results indicate distinct behaviors among these liquids under highly divergent AC sinusoidal and impulse electric field. Dibenzyltoluene demonstrates excellent feature in suppressing discharges even at elevated temperature. In synthetic ester, positive discharges appeared to be less numerous but extremely high up to several nC in amplitude are strongly related to the further breakdown. Streamers inception voltage which denotes the initial discharges properties and streamer propagation velocity varies from several m/s up to order of km/s, show less dependency to temperature instead of the intrinsic characteristic of liquid itself. These prebreakdowns phenomena constitute interesting information in planning and selecting insulation liquids and analyzing fundamental mechanism during the operation and maintenance for HV utility applications.
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- 2020
11. Modelling of current and temperature rise during discharge initiation in water
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P. Adda, Nadia Boussetta, R. Hanna, Eugène Vorobiev, Olivier Lesaint, Laboratoire de Génie Electrique de Grenoble (G2ELab), and Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])
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010302 applied physics ,Maximum bubble pressure method ,Materials science ,[SPI.NRJ]Engineering Sciences [physics]/Electric power ,04 agricultural and veterinary sciences ,Mechanics ,Impulse (physics) ,040401 food science ,01 natural sciences ,Temperature measurement ,law.invention ,Physics::Fluid Dynamics ,Ignition system ,0404 agricultural biotechnology ,Electrical resistivity and conductivity ,law ,Boiling ,Electric field ,0103 physical sciences ,Electrical and Electronic Engineering ,ComputingMilieux_MISCELLANEOUS ,Voltage - Abstract
The conduction current recorded when a high voltage impulse is applied to a rod-plane gap containing water is modelled. The electro/thermal model considers the coupling between electric field, Joule dissipation, temperature rise, and variation of liquid resistivity with temperature. A fairly good agreement between current measurements and calculations are obtained. The model also shows the evolution of temperature and field distributions in the gap versus time. The calculated average temperatures appear insufficient to explain liquid boiling. Boiling can be explained by considering the influence of local surface defects. Values of the bubble pressure at discharge ignition are evaluated, with the hypothesis that discharges occur in vapor following Paschen's law.
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- 2018
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12. Vapor bubble and streamer initiation in water under long duration impulses
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Nadia Boussetta, Eugène Vorobiev, P. Adda, Olivier Lesaint, Garcia, Sylvie, Laboratoire de Génie Electrique de Grenoble (G2ELab), and Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])
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Materials science ,Drop (liquid) ,Bubble ,[SPI.NRJ]Engineering Sciences [physics]/Electric power ,High voltage ,04 agricultural and veterinary sciences ,Mechanics ,Conductivity ,Dissipation ,040401 food science ,Physics::Fluid Dynamics ,0404 agricultural biotechnology ,Schlieren ,Electrical measurements ,Electrical and Electronic Engineering ,ComputingMilieux_MISCELLANEOUS ,Physics::Atmospheric and Oceanic Physics ,[SPI.NRJ] Engineering Sciences [physics]/Electric power ,Voltage - Abstract
The generation of vapor bubbles in water under high voltage impulses of long duration (500 μs) is investigated experimentally. In most cases, the appearance of bubbles is followed by the inception of discharges occurring within the vapor, eventually transforming the bubble into a propagating streamer. Time delays to bubble and discharge inception are measured versus conductivity and voltage, using fast visualization and optical detection of bubbles. Before bubble inception, the liquid heating and the onset of an electro-hydro-dynamic (EHD) motion can be observed by Schlieren visualization. Electrical measurements show a decrease of the gap resistance versus time, attributable to the heating of water. When conductivity and voltage are changed, the onset of bubble inception is correlated to a nearly constant resistance drop, suggesting that a constant temperature is present when bubbles appear. At short times, the energy dissipation required to observing bubbles is independent of conductivity and applied voltage. Experiments show that vapor bubble generation results from a competition between liquid heating by Joule dissipation, and forced cooling induced by the EHD motion.
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- 2018
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13. Streamer Generation and Propagation in Dibenzyltoluene and Ester liquids under High Temperature
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Joko Muslim, Ngapuli I. Sinisuka, Rachelle Hanna, Olivier Lesaint, Laboratoire de Génie Electrique de Grenoble (G2ELab), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Université de Bandung, and Garcia, Sylvie
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010302 applied physics ,Materials science ,020209 energy ,[SPI.NRJ]Engineering Sciences [physics]/Electric power ,Dibenzyltoluene ,02 engineering and technology ,7. Clean energy ,01 natural sciences ,Characterization (materials science) ,Chemical physics ,Power electronics ,0103 physical sciences ,0202 electrical engineering, electronic engineering, information engineering ,ComputingMilieux_MISCELLANEOUS ,[SPI.NRJ] Engineering Sciences [physics]/Electric power ,Voltage - Abstract
The characterization of pre-breakdown streamers in liquids is carried out under high temperature up to 200°C. Measurements are obtained either in a high temperature non-polar liquid (dibenzyltoluene, DBT), or in a synthetic ester (Midel®7131) for comparison. Streamer inception voltages are measured in both polarities, as well as propagation velocities. The results obtained show that only minor modifications are recorded when temperature is raised up to 200°C. Due to its stability at high temperature, DBT constitutes an interesting solution in the perspective of using liquids for the insulation of high temperature power electronics.
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- 2019
14. Partial Discharge Measurements on Dibenzyltoluene for High Temperature Encapsulant Application up to 350°C
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Joko Muslim, Ngapuli I. Sinisuka, Rachelle Hanna, Olivier Lesaint, Laboratoire de Génie Electrique de Grenoble (G2ELab), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Université de Bandung, and Garcia, Sylvie
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010302 applied physics ,Materials science ,020209 energy ,[SPI.NRJ]Engineering Sciences [physics]/Electric power ,Analytical chemistry ,chemistry.chemical_element ,High voltage ,Dibenzyltoluene ,02 engineering and technology ,Dielectric ,Nitride ,Silicone Gels ,01 natural sciences ,Condensed Matter::Materials Science ,chemistry ,Aluminium ,visual_art ,0103 physical sciences ,Partial discharge ,0202 electrical engineering, electronic engineering, information engineering ,visual_art.visual_art_medium ,Ceramic ,ComputingMilieux_MISCELLANEOUS ,[SPI.NRJ] Engineering Sciences [physics]/Electric power - Abstract
Partial discharges characterization on ceramic substrates and dielectric liquids under high temperature up to $350^{\circ}\mathrm{C}$ is investigated. Aluminum nitride (AlN) and alumina (Al 2 O 3 substrates, and a high temperature non-polar dibenzyltoluene (DBT) liquid are used. Several complementary measurements are also done in a synthetic ester liquid. PD measurements on AlN substrates embedded in DBT show a good behavior up to $300^{\circ}\mathrm{C}$, and up to $350^{\circ}\mathrm{C}$ with Alumina. This shows that high temperature insulating liquid may constitute a good alternative to silicone gels for the encapsulation of power electronics circuits at high temperature and high voltage. The comparison between PD characteristics in the liquid alone and with substrates show that PDs mostly occur within the ceramic material at temperatures up to $300^{\circ}\mathrm{C}$.
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- 2019
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15. Prebreakdown and Breakdown in Liquid Nitrogen under Pulsed Heating for Superconducting
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Olivier Lesaint, Olivier Gallot-Lavallée, Pierre Legendre, Christophe Creusot, Alain Girodet, Nelly Bonifaci, and Raphael Chassagnoux
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010302 applied physics ,Superconductivity ,Quenching ,Materials science ,business.industry ,High voltage ,Liquid nitrogen ,01 natural sciences ,Boiling ,0103 physical sciences ,Electrode ,Optoelectronics ,010306 general physics ,business ,Polarity (mutual inductance) ,Voltage - Abstract
An experimental study of breakdown and pre-breakdown phenomena in liquid nitrogen (LN 2 ) is performed in this work, aiming to provide useful knowledge for the design of high voltage superconducting systems. A metallic tape subjected to pulsed heating is used as ground electrode to properly simulate the operating conditions of a quenching superconducting apparatus. Measurements of breakdown voltages between the tape and a plane electrode tied to high voltage show the strong influence of tape polarity, LN 2 temperature, and delay between heating and voltage application. Various measurements obtained with either a highspeed camera or an intensified camera allow to characterize the sequence of pre-breakdown events (i.e. liquid boiling, vapor bubble development, and streamer propagation) leading to breakdown.
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- 2019
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16. Electrical Characterization of Dibenzyltoluene Liquid at High Temperatures up to 350°C
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Jean-Luc Reboud, Joko Muslim, Rachelle Hanna, Olivier Lesaint, Ngapuli I. Sinisuka, Laboratoire de Génie Electrique de Grenoble (G2ELab), and Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])
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010302 applied physics ,Materials science ,020208 electrical & electronic engineering ,[SPI.NRJ]Engineering Sciences [physics]/Electric power ,Electrical breakdown ,02 engineering and technology ,Atmospheric temperature range ,01 natural sciences ,7. Clean energy ,Temperature measurement ,law.invention ,Pressure measurement ,law ,Boiling ,0103 physical sciences ,Electrode ,0202 electrical engineering, electronic engineering, information engineering ,Breakdown voltage ,Composite material ,ComputingMilieux_MISCELLANEOUS ,Voltage - Abstract
Electrical breakdown properties of Dibenzyltoluene (DBT) are investigated over wide temperature range (from room temperature up to 350°C), and under pressure variation « 1 kPa to 200 kPa). The purpose is to investigate the suitability of DBT as potential insulating material for high temperature applications, such as encapsulant in high temperature power electronics modules. Measurements were carried out using a special high temperature test cell, under nitrogen atmosphere. Sphere-sphere electrodes and voltage ramp were used. Results show some reduction of breakdown voltage at high temperature, down to 58.2% at 350°C. A similar effect is observed when pressure is reduced. This reduction occurs when the liquid approaches boiling conditions, hence facilitating the appearance of vapor bubbles.
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- 2018
17. Positive Streamer Inception in Cyclohexane: Experimental Characterization and Cavitation Mechanisms
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L. Costeanu, Olivier Lesaint, Laboratoire de Génie Electrique de Grenoble (G2ELab), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), and Garcia, Sylvie
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010302 applied physics ,Materials science ,Polarity symbols ,[SPI.NRJ]Engineering Sciences [physics]/Electric power ,Slew rate ,Mechanics ,Impulse (physics) ,01 natural sciences ,Threshold voltage ,Temporal resolution ,Cavitation ,Boiling ,0103 physical sciences ,Electrical and Electronic Engineering ,010306 general physics ,ComputingMilieux_MISCELLANEOUS ,Voltage ,[SPI.NRJ] Engineering Sciences [physics]/Electric power - Abstract
This paper deals with physical processes involved during inception of positive streamers in liquid cyclohexane. The inception of streamers is detected with a high temporal resolution by measurements of charge, visualization, and detection of phase change by scattered laser light. These techniques allow us to obtain measurements of inception voltages and inception delay time in various conditions of impulse voltage with different slew rates, and pressure. In positive polarity, a minimum "formative time" close to 40 ns is observed, as well as a large influence of both pressure and slew rate. The hypothesis of cavitation induced by the EHD motion, and liquid boiling due to heat dissipation are considered to explain positive streamer inception.
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- 2018
18. Dibenzyltoluene Liquid Characterization: DC and AC Breakdown Measurement at High Temperature Range up to 350°C
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Joko Muslim, Rachelle Hanna, Olivier Lesaint, Jean-Luc Reboud, Ngapuli Irmea Sinisuka, Laboratoire de Génie Electrique de Grenoble (G2ELab), and Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])
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[SPI.NRJ]Engineering Sciences [physics]/Electric power ,ComputingMilieux_MISCELLANEOUS - Abstract
International audience
- Published
- 2018
19. Breakdown of liquids in long gaps: influence of distance, impulse shape, liquid nature, and interpretation of measurements
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Olivier Lesaint, F. Mc Cluskey, André Denat, Laboratoire de Génie Electrique de Grenoble (G2ELab), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS), Laboratoire des Écoulements Géophysiques et Industriels [Grenoble] (LEGI), and Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)
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010302 applied physics ,Chemistry ,020209 energy ,[SPI.NRJ]Engineering Sciences [physics]/Electric power ,Electric breakdown ,Analytical chemistry ,Electrical breakdown ,High voltage ,02 engineering and technology ,Mechanics ,Large range ,Impulse (physics) ,01 natural sciences ,13. Climate action ,0103 physical sciences ,Electrode ,0202 electrical engineering, electronic engineering, information engineering ,Breakdown voltage ,Electrical and Electronic Engineering ,Voltage - Abstract
International audience; Breakdown measurements are carried out in liquids under point-sphere and pointplane electrode geometries, over a large range of gap distances up to 35 cm. Non-polar hydrocarbon liquids with different chemical structures are studied: saturated, aromatic, polyaromatic, mineral oils, and ester. Two high voltage impulse shapes are used: the standard lightning impulse (LI), and a specific “step” impulse (ST). Step impulses are favorable to interpret breakdown measurements since the applied voltage remains constant while prebreakdown streamers propagate. Conversely, with lightning impulse and long gaps the propagation of streamers with a low propagation velocity (a few km/s) is quenched due to the rapidly decaying voltage. In this case, breakdown can result only from the propagation of faster streamers, which appear in very different conditions according to the liquid nature. The results obtained allow us to interpret the large variations of breakdown voltage observed in large gaps, when either the high voltage impulse shape or the liquid nature is changed. These results also help to define proper conditions for testing and comparing liquids. Testing with lightning impulse in short gaps, such as in standard tests, does not provides data relevant for very high voltage applications.
- Published
- 2015
- Full Text
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20. Influence of the solid material nature on the inception of creeping discharges in air
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François Gentils, Nelly Bonifaci, L. Tremas, Olivier Lesaint, B. Ohl, Laboratoire de Génie Electrique de Grenoble ( G2ELab ), Université Joseph Fourier - Grenoble 1 ( UJF ) -Institut polytechnique de Grenoble - Grenoble Institute of Technology ( Grenoble INP ) -Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique ( CNRS ) -Université Grenoble Alpes ( UGA ), Schneider Electric ( SE ), Schneider Electric, Groupe Schneider Electric, Laboratoire de Génie Electrique de Grenoble (G2ELab), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Schneider Electric ( SE), and Garcia, Sylvie
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010302 applied physics ,Permittivity ,Materials science ,Atmospheric pressure ,[SPI.NRJ]Engineering Sciences [physics]/Electric power ,Glass fiber ,Epoxy ,Impulse (physics) ,01 natural sciences ,010305 fluids & plasmas ,Polyolefin ,chemistry.chemical_compound ,[ SPI.NRJ ] Engineering Sciences [physics]/Electric power ,chemistry ,visual_art ,0103 physical sciences ,visual_art.visual_art_medium ,Composite material ,Polycarbonate ,ComputingMilieux_MISCELLANEOUS ,[SPI.NRJ] Engineering Sciences [physics]/Electric power ,Voltage - Abstract
An experimental study of discharges in air at atmospheric pressure under impulse voltage, creeping on insulating solid surface is presented. The objective is to get a better understanding of creeping discharge by studying streamer initiation and propagation, and by looking at the influence of the nature of the insulating solid. Several solid materials, of different chemical natures and permittivity are investigated. Pre-breakdown streamers are investigated by high speed visualization and transient current measurements. In the presence of insulating solids such as epoxy resin, PPA/glass fibers and polycarbonate, surface streamers appear during the voltage rise, and the time delay to appearance is correspondingly rather short. With two materials of polyolefin and fluorine modified polyolefin families, characterized by lower permittivity, the first creeping streamer appears at the maximum voltage after a much longer statistical time delay, very close to that obtained in air without solid.
- Published
- 2017
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21. Positive streamer inception in cyclohexane: evidence of formative time and cavitation process
- Author
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L. Costeanu, Olivier Lesaint, Laboratoire de Génie Electrique de Grenoble (G2ELab), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), and Garcia, Sylvie
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010302 applied physics ,Physics ,Cyclohexane ,Hydrostatic pressure ,Polarity symbols ,[SPI.NRJ]Engineering Sciences [physics]/Electric power ,High voltage ,Mechanics ,Impulse (physics) ,01 natural sciences ,chemistry.chemical_compound ,chemistry ,Temporal resolution ,Cavitation ,0103 physical sciences ,ComputingMilieux_MISCELLANEOUS ,Voltage ,[SPI.NRJ] Engineering Sciences [physics]/Electric power - Abstract
This paper deals with physical processes involved during streamer inception in liquid cyclohexane under impulse voltage. In point-plane geometry, the inception of streamers is detected with a high temporal resolution (about 1 ns) by measurement of charge, visualization, and detection of phase change by scattered laser light. These techniques allow us to obtain precise measurements of the inception delay time, versus applied voltage and hydrostatic pressure. Measurements carried out in positive and negative polarity with a fast impulse voltage (20 ns risetime) show a large difference. In positive polarity, a minimum "formative time" close to 45 ns is observed, while negative streamers can appear almost immediately at high voltage. The hypothesis of cavitation induced by the EHD motion is considered to explain positive streamer inception.
- Published
- 2017
22. Electrical Characterization of Esters Liquid at High Temperatures above 200°C
- Author
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Joko Muslim, Rachelle Hanna, Olivier Lesaint, Jean-Luc Reboud, Sinisuca, N. I., Laboratoire de Génie Electrique de Grenoble (G2ELab), and Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])
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[SPI.NRJ]Engineering Sciences [physics]/Electric power ,ComputingMilieux_MISCELLANEOUS - Abstract
International audience
- Published
- 2017
23. Advanced spectral diagnostics to study electrical discharges in dense fluids
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Z. Li, Nelly Bonifaci, K. von Haeften, Jussi Eloranta, Olivier Lesaint, V.M. Atrazhev, and V. A. Shakhatov
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010302 applied physics ,Materials science ,Physics::Plasma Physics ,Plasma parameters ,0103 physical sciences ,Electron ,Impulse (physics) ,Neutral particle ,01 natural sciences ,Astrophysics::Galaxy Astrophysics ,010305 fluids & plasmas ,Computational physics ,Voltage - Abstract
Breakdown, at least in point-plane geometry, is the result of inception and propagation of pre-breakdown phenomena called "streamers". The purpose of the present investigation is a spectroscopic measurement of the essential plasma parameters, i.e. the gas temperature and the neutral particle and electron densities. In this paper we focus our spectroscopic investigation on fast positive filamentary streamers obtained at large gap distance under high impulse voltage in LN 2 .
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- 2017
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24. Electrical characterization of synthetic ester liquid over wide temperature range (−60°C / 200°C)
- Author
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Jean-Luc Reboud, Ngapuli I. Sinisuka, Rachelle Hanna, Olivier Lesaint, and Joko Muslim
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010302 applied physics ,Permittivity ,Materials science ,020208 electrical & electronic engineering ,Analytical chemistry ,Relative permittivity ,02 engineering and technology ,Dielectric ,Atmospheric temperature range ,Conductivity ,01 natural sciences ,Orders of magnitude (specific energy) ,0103 physical sciences ,0202 electrical engineering, electronic engineering, information engineering ,Dissipation factor ,Dielectric loss - Abstract
Dielectric properties of synthetic ester oil are investigated in wide frequency range (10 mHz–1 MHz) and temperature (−60°C −200°C) ranges. The aim is to determine the ability of liquid insulation, to be used as encapsulating materials for high temperature power electronics modules. As far as the ester remains in liquid state (above approximately −16°C), a typical frequency spectrum of the dissipation factor tan δ with two parts is observed. At low frequency, dielectric losses (tan δ > 0.10) are due to ionic conduction, and at high frequency losses are mainly due to dipolar relaxation. When temperature is increased, losses increase at low frequency, and decrease at high frequency. Results show that the liquid conductivity increases by more than 3 orders of magnitude between room temperature and 200°C. A slight decrease of permittivity is also observed, correlated to the lowering of density at high temperature. This behavior totally changes when the ester becomes a gel at low temperature. Dielectric relaxations reminiscent of solid materials then appear.
- Published
- 2017
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25. Recommendations for surface conductivity characterisation under High Voltage Direct Current (HVDC)
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C-T. Vu, L. Zavattoni, Alain Girodet, Rachelle Hanna, Paul Vinson, and Olivier Lesaint
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010302 applied physics ,Materials science ,business.industry ,Electrical engineering ,Conductivity ,Thermal conduction ,01 natural sciences ,Engineering physics ,Surface conductivity ,Work (electrical) ,Volume (thermodynamics) ,Electric field ,0103 physical sciences ,High-voltage direct current ,business ,Voltage - Abstract
Gas Insulated Substation (GIS) under High Voltage Direct Current (HVDC) are becoming widely investigated with the development of DC networks. Under DC voltage, mechanism of charge accumulation on the insulation surface is of major importance since it may distort the electric field distribution. The latter directly depends on material's conduction and so, on its volume and surface conductivities. Previous work has evidenced that those properties are influenced by the temperature, the electric field and the surrounding relative humidity [1-3]. The insulation characteristics must be clarified to allow a better estimation of the electric field distribution, as well as a better insulation design.
- Published
- 2017
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26. A study of mechanisms involved during the extraction of polyphenols from grape seeds by pulsed electrical discharges
- Author
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Nadia Boussetta, Olivier Lesaint, and Eugen Vorobiev
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0106 biological sciences ,Shock wave ,Chemistry ,Extraction (chemistry) ,Analytical chemistry ,04 agricultural and veterinary sciences ,General Chemistry ,040401 food science ,01 natural sciences ,Industrial and Manufacturing Engineering ,Arc (geometry) ,0404 agricultural biotechnology ,Polyphenol ,010608 biotechnology ,Phase (matter) ,Electric field ,Cell shape ,Relevant information ,Food Science - Abstract
This paper presents an experimental study of the influence of pulsed electrical discharges of low energy (3 to 10 J) on the extraction of polyphenols from grape seeds. To obtain a better understanding, three basic phenomena involved in the whole discharge process are studied separately: pulsed electric field (PEF), pre-breakdown phase (streamer), and breakdown phase (arc). The polyphenol extraction is much more efficient with arcs, compared to streamers and PEF. Therefore, during the discharge process, the enhancement of polyphenol extraction can be mainly ascribed to the final arc phase. The total energy per unit mass CWp required to extract 5000 mg GAE/100 g DM with the arc (CWp = 16 kJ/kg) is 27 times lower compared to streamers alone, and 47 times lower compared to PEF. An optical study shows that the mechanical effects of arcs (shock waves, expanding cavity, and strong turbulence) are much more pronounced compared to streamers. These mechanical effects are responsible for the fragmentation of grape seeds, and strongly promote the release of polyphenols. Other parameters such as the test cell shape and the inter-electrode distance also show that the polyphenol extraction is further enhanced when grape seeds are in close proximity with the breakdown arc. In optimized conditions, the extraction efficiency with low energy discharges can be significantly higher than previous measurements with high energy discharges. Industrial relevance This paper presents relevant information for the design of generating electrical discharges treatment. The study also addresses a specific case of use of by-products and shows the effectiveness of such technology.
- Published
- 2013
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27. Dark current measurements in humid SF6 at high uniform electric field
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Rachelle Hanna, Olivier Lesaint, and L. Zavattoni
- Subjects
010302 applied physics ,Physics ,Electric field ,0103 physical sciences ,02 engineering and technology ,Atomic physics ,021001 nanoscience & nanotechnology ,0210 nano-technology ,01 natural sciences ,Computational physics ,Dark current - Published
- 2016
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28. Study of Surface Resistivity of an Epoxy/Gas Interface versus Electric Field and Relative Humidity
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Olivier Lesaint, Rachelle Hanna, L. Zavattoni, Olivier Gallot-Lavallée, Laboratoire de Génie Electrique de Grenoble (G2ELab), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), and Siemens
- Subjects
010302 applied physics ,Materials science ,[SPI.NRJ]Engineering Sciences [physics]/Electric power ,Analytical chemistry ,Conductivity ,01 natural sciences ,Temperature measurement ,Sulfur hexafluoride ,chemistry.chemical_compound ,Volume (thermodynamics) ,chemistry ,Electrical resistivity and conductivity ,Electric field ,0103 physical sciences ,Relative humidity ,Current (fluid) - Abstract
International audience; Surface resistivity of solid insulators is usuallydetermined by measuring the current induced when an electricfield tangential to the surface is applied. This classical methodcan become questionable when the electric field is raised. In fact,a current may also flow above the interface through the humidgas, in addition to currents flowing at the interface and below theinterface within the solid bulk. This paper presents anexperimental study of the variation of the surface resistivityversus electric field and relative humidity RH of the surroundinggas. The results show that in dry gas (RH < 1%) and for anelectric field up 8 kV/mm, the surface gets no specific propertiescompared to the volume. However, in humid gas (1% < RH
- Published
- 2016
29. Prebreakdown phenomena in liquids: propagation 'modes' and basic physical properties
- Author
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Olivier Lesaint, Laboratoire de Génie Electrique de Grenoble (G2ELab), and Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])
- Subjects
010302 applied physics ,Materials science ,Acoustics and Ultrasonics ,0103 physical sciences ,[SPI.NRJ]Engineering Sciences [physics]/Electric power ,Condensed Matter Physics ,01 natural sciences ,010305 fluids & plasmas ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials - Published
- 2016
- Full Text
- View/download PDF
30. High-Voltage Electrical Discharge Assisted Extraction of Phenolic Compounds from Grape Seeds
- Author
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Nadia Boussetta, Olivier Lesaint, Eugène Vorobiev, and P. Adda
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Horticulture ,Chromatography ,Chemistry ,Extraction (chemistry) ,High voltage ,Electric discharge - Published
- 2016
- Full Text
- View/download PDF
31. Breakdown in air along insulating solid surfaces of different natures, parallel or perpendicular to the field direction
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Nelly Bonifaci, L. Tremas, Olivier Lesaint, François Gentils, B. Ohl, Chadebec, Olivier, Laboratoire de Génie Electrique de Grenoble (G2ELab), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Schneider Electric ( SE), and Schneider Electric Industries S.A.S.
- Subjects
010302 applied physics ,Materials science ,Condensed matter physics ,Field (physics) ,business.industry ,Solid surface ,[SPI.NRJ]Engineering Sciences [physics]/Electric power ,01 natural sciences ,010305 fluids & plasmas ,Optics ,0103 physical sciences ,Perpendicular ,business ,ComputingMilieux_MISCELLANEOUS ,[SPI.NRJ] Engineering Sciences [physics]/Electric power - Abstract
International audience
- Published
- 2016
32. Observation and modelling of vapor bubble and streamer initiation in water under long duration impulses
- Author
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Nadia Boussetta, Eugène Vorobiev, Olivier Lesaint, P. Adda, Laboratoire de Génie Electrique de Grenoble (G2ELab), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Transformation Intégrée de la Matière Renouvelable (TIMR), Université de Technologie de Compiègne (UTC), and Chadebec, Olivier
- Subjects
0404 agricultural biotechnology ,Materials science ,[SPI.NRJ]Engineering Sciences [physics]/Electric power ,Vapor bubble ,04 agricultural and veterinary sciences ,Atmospheric sciences ,040401 food science ,Short duration ,ComputingMilieux_MISCELLANEOUS ,[SPI.NRJ] Engineering Sciences [physics]/Electric power - Abstract
International audience
- Published
- 2016
33. Partial discharges at a triple junction metal/solid insulator/gas and simulation of inception voltage
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Lucian Caliap, Nelly Bonifaci, André Denat, C. Tran Duy, P. Ponchon, Olivier Lesaint, Alain Girodet, and B. Gelloz
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business.industry ,Chemistry ,Triple junction ,Analytical chemistry ,Insulator (electricity) ,High voltage ,Condensed Matter Physics ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Electric field ,Partial discharge ,Electrode ,Optoelectronics ,Electrical and Electronic Engineering ,business ,Electrical conductor ,Biotechnology ,Voltage - Abstract
In gas-insulated systems, the presence of solid insulators used to hold conductors at high voltage induces the presence of triple interfaces where the metal, solid insulator and gas are in contact. These regions, usually named “triple junction”, constitute weak points for the insulation, mainly due to the mismatch between permittivities of solid and gas, which induces an enhancement of the electric field. If the design of these regions is not carried out with great care, partial discharges (PDs) may appear and accelerate the ageing of the insulator. This paper deals with an experimental study of PDs in a “triple junction” electrode configuration, carried out with sensitive electrical and optical PD measurements. Experiments are done in two pure gases, nitrogen and SF6. Two discharge regimes can be observed: very small discharges (
- Published
- 2008
- Full Text
- View/download PDF
34. Electrical breakdown voltage in micro- and submicrometer contact gaps (100nm - 10µm) in air and nitrogen
- Author
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Christophe Poulain, Nelly Bonifaci, Alexis Peschot, and Olivier Lesaint
- Subjects
Avalanche diode ,Condensed matter physics ,Chemistry ,Electric field ,Electrode ,Electrical breakdown ,Analytical chemistry ,Breakdown voltage ,Plasma ,Voltage ,Radius of curvature (optics) - Abstract
In this paper, we present the results of electrical breakdown experiments performed in a contact gap ranging from 100nm to 10µm under air and nitrogen environment. The electrodes arrangement corresponds to a point-plane system and consists in a probe tip with a radius of curvature of 20µm and a perfectly flat electrode. A high precision piezoelectric actuator provides to the system a static resolution of ±30nm allowing to investigate submicrometer contact gaps. Numerous experiments have been performed at those distances (
- Published
- 2015
- Full Text
- View/download PDF
35. Structure effect of thin film polypropylene view by dielectric spectroscopy and X-ray diffraction: Application to dry type power capacitors
- Author
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Abdelkader Kahouli, Laurent Heux, Olivier Gallot-Lavallée, Pascal Rain, Jean-Marc Lupin, Olivier Lesaint, and C. Guillermin
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Permittivity ,Materials science ,Polymers and Plastics ,business.industry ,General Chemistry ,Dielectric ,Atmospheric temperature range ,Surfaces, Coatings and Films ,Dielectric spectroscopy ,Crystallinity ,Optics ,Lamella (surface anatomy) ,Materials Chemistry ,Dissipation factor ,Thin film ,Composite material ,business - Abstract
This work reports on the relationship between structure and dielectric properties of biaxially oriented polypropylene. The morphology of semicrystalline bioriented isotactic polypropylene films is investigated using wide angle X-ray diffraction and Polarized Optical Microscopy. A b-orthorhombic structure, with a crystallinity ratio of about 46%, and “Crater” morphology of the b-form is identified. Dielectric properties are measured by Broadband Dielectric Spectroscopy over a wide temperature range (2150 to 1258C). Since the dissipation factor of the PP is very low, special care was taken to obtain valid data. Two main relaxation processes are observed: a a-relaxation peak associated to the glass transition temperature (Tg) at temperature about 278C, and a broad b*-relaxation at about 2608C, partly attributed to CH orientation. The variation of the dissipation factor versus sample thickness (from 3.8 to 11.8 mm) is correlated and partly explained by the increase of crystallinity ratio and lamella size at larger thicknesses. It comes out that the thinnest film seems perfectly meet the application requesting, namely lowest dissipation factor and highest permittivity.
- Published
- 2015
- Full Text
- View/download PDF
36. Dielectric features of two grades of bi-oriented isotactic polypropylene
- Author
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Jean-Marc Lupin, Olivier Lesaint, Abdelkader Kahouli, Olivier Gallot-Lavallée, Pascal Rain, and C. Guillermin
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Polypropylene ,Materials science ,Polymers and Plastics ,General Chemistry ,Dielectric ,Atmospheric temperature range ,Thermal conduction ,Surfaces, Coatings and Films ,Dielectric spectroscopy ,law.invention ,chemistry.chemical_compound ,Capacitor ,chemistry ,law ,Polymer chemistry ,Materials Chemistry ,Ionic conductivity ,Dielectric loss ,Composite material - Abstract
The dielectric properties of two grades of bi-oriented isotactic polypropylene were studied with a variety of techniques: breakdown field measurements, dielectric spectroscopy, thermally stimulated depolarization currents (Is), and direct-current (dc) conduction I values. Standard polypropylene (STPP) and high-crystallinity polypropylene (HCPP) films were investigated. Measurements were carried out over a wide temperature range (2150C/1125C). The breakdown fields in both materials showed a very small difference. On the other hand, the dielectric losses and dc conduction I values were significantly lower in HCPP. Both materials showed a decrease in the dielectric loss versus temperature in the range 20–90C; this is favorable for application in alternating-current power capacitors. The analysis of the dc I value allowed us to find evidence of two main conduction mechanisms: (1) below 80C in both materials, a hopping mechanism due to the motion of electrons occurred in the amorphous phase, and (2) above 80C, ionic conduction occurred in HCPP, and hopping conduction occurred in STPP.
- Published
- 2015
- Full Text
- View/download PDF
37. Solid/Gaseous Insulation Systems for Compact HVDC Solutions
- Author
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Winter, A., Kindersberger, J., Tenzer, M., Hinrichsen, V., Zavattoni, L., olivier lesaint, Muhr, M., Imamovic, D., Laboratoire de Génie Electrique de Grenoble (G2ELab), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS), and Garcia, Sylvie
- Subjects
[SPI.NRJ]Engineering Sciences [physics]/Electric power ,ComputingMilieux_MISCELLANEOUS ,[SPI.NRJ] Engineering Sciences [physics]/Electric power - Abstract
International audience
- Published
- 2015
38. Etude de décharges électriques dans l'eau
- Author
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André Denat, Juan Nieto Salazar, and Olivier Lesaint
- Subjects
Chemistry ,General Medicine - Published
- 2004
- Full Text
- View/download PDF
39. Prebreakdown phenomena at high voltage in liquid nitrogen and comparison with mineral oil
- Author
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S. Lelaidier, Nelly Bonifaci, P.E. Frayssines, F. Devaux, Olivier Lesaint, and André Denat
- Subjects
Cryostat ,Materials science ,Streak camera ,Hydrostatic pressure ,Analytical chemistry ,Breakdown voltage ,High voltage ,Dielectric ,Electrical and Electronic Engineering ,Liquid nitrogen ,Atomic physics ,Threshold voltage - Abstract
This paper presents a study of prebreakdown phenomena (usually called streamers) occurring at high voltage in liquid nitrogen. A special cryostat has been constructed to allow dielectric measurements in liquid nitrogen up to 200 kV, and 0.5 MPa hydrostatic pressure. Streamers are detected and studied with various techniques: high speed visualization, streak camera, and recording of transient currents and emitted light. The propagation of positive and negative streamers is investigated at gap distances up to 80 mm. Streamers are then compared to similar phenomena observed in mineral oil. In liquid nitrogen, streamers are different compared to mineral oil. A transition from slow to fast positive streamers (velocity about 10 km/s) is observed at a threshold voltage below the breakdown voltage. The hydrostatic pressure has almost no influence on this phenomenon. Some experiments carried out with a solid barrier perpendicular to the gap axis are also presented. The practical consequences for the design of HV insulation in superconducting systems are then discussed.
- Published
- 2002
- Full Text
- View/download PDF
40. Localisation de décharges partielles dans un bobinage. Etude d’une méthode basée sur l’analyse spectrale des courants mesurés aux extrémités
- Author
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Hervé Debruyne, Olivier Lesaint, olivier Moreau, Philippe Guinic, and Jean Poitevin
- Subjects
General Medicine - Published
- 2002
- Full Text
- View/download PDF
41. Streamers in liquid nitrogen: characterization and spectroscopic determination of gaseous filament temperature and electron density
- Author
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P.E. Frayssines, Nelly Bonifaci, André Denat, and Olivier Lesaint
- Subjects
Electron density ,Acoustics and Ultrasonics ,Hydrogen ,Polarity symbols ,Analytical chemistry ,Balmer series ,chemistry.chemical_element ,Liquid nitrogen ,Condensed Matter Physics ,Molecular physics ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Protein filament ,symbols.namesake ,Stark effect ,chemistry ,symbols ,Light emission - Abstract
Streamers initiated in point-plane electrode geometry under impulse voltage are studied. Characterization up to 30 kV in both polarities shows two streamer types. In negative polarity, only slow `bush-like' streamers with a velocity of about 100 m s-1 are observed. In positive polarity, both `bush-like' and filamentary streamers appear. Positive `bush-like' streamers have similar velocity as in negative polarity, whereas filamentary streamers have a propagation velocity up to 30 km s-1. This high velocity is correlated to large transient current and light emission. Spectroscopic study of the light emitted by filaments shows mainly the second positive system of nitrogen. This system allows us to estimate the gas temperature inside a filament by making a comparison with a numerically simulated spectrum. A temperature close to 500 K is found. Dilution of hydrogen gas in liquid nitrogen allows us to determine also the electron density by Stark broadening of the Balmer Hα line. An electron density of about 1.1018 cm-3 is found.
- Published
- 2002
- Full Text
- View/download PDF
42. Streamer propagation in mineral oil in semi-uniform geometry
- Author
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T.V. Top, G. Massala, and Olivier Lesaint
- Subjects
Physics ,Field (physics) ,Physics::Instrumentation and Detectors ,Transformer oil ,Plane (geometry) ,Geometry ,Parallel plane ,Physics::Plasma Physics ,Electrode ,medicine ,Point (geometry) ,Uniform field ,Electrical and Electronic Engineering ,Mineral oil ,medicine.drug - Abstract
Presents a study of streamer propagation in transformer oil, with point-plane and semi-uniform geometry. The latter is made of parallel plane electrodes, with a thin triggering point of calibrated size. By reducing the length of the point, it is possible to move progressively from a point-plane geometry to a quasi uniform geometry. The propagation of streamers is impeded by the presence of a metallic plane behind the triggering point, that reduces the field on propagating streamers. The effect varies widely according to the streamer type considered. The propagation of negative and fast positive streamers is nearly quenched, whereas slower filamentary positive streamers (usually responsible for breakdown in oil) are less affected. This shows that many results obtained in point-plane geometry can not be simply extrapolated to the more realistic case of uniform field.
- Published
- 2002
- Full Text
- View/download PDF
43. Streamer initiation in mineral oil. Part I: electrode surface effect under impulse voltage
- Author
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T.V. Top and Olivier Lesaint
- Subjects
Materials science ,Transformer oil ,Analytical chemistry ,Radius ,Impulse (physics) ,Rod ,Electrode ,medicine ,Breakdown voltage ,Electrical and Electronic Engineering ,Atomic physics ,Mineral oil ,Voltage ,medicine.drug - Abstract
Presents a study of streamer inception in mineral transformer oil, in point-plane and rod-plane geometry under impulse voltage. The measurements performed with points and rods over a wide range of tip radii show a marked decrease of initiation fields when the electrode radius is increased. The initiation field is divided by 30 over the investigated range (from 1 /spl mu/m points up to 2 cm rods). This effect compares fairly well with the "surface effect" known for breakdown voltages under uniform field with large electrodes. Plotting these results together shows the decrease of streamer initiation fields over a very wide electrode surface range (12 decades), proportional to S/sup -0.17/ (S: electrode surface area, cm/sup 2/). These results suggest the influence of electrode surface defects on streamer initiation under impulse voltage.
- Published
- 2002
- Full Text
- View/download PDF
44. Streamer and Breakdown Phenomena Under Step and Lightning Impulses in Various Hydrocarbon Liquids
- Author
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F. Mc Cluskey, Olivier Lesaint, André Denat, Laboratoire des Écoulements Géophysiques et Industriels [Grenoble] (LEGI), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Génie Electrique de Grenoble (G2ELab), and Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS)
- Subjects
chemistry.chemical_classification ,Hydrocarbon ,business.industry ,Chemistry ,[SPI.NRJ]Engineering Sciences [physics]/Electric power ,Electrical engineering ,Electrical breakdown ,business ,Lightning ,Engineering physics ,ComputingMilieux_MISCELLANEOUS - Abstract
International audience
- Published
- 2014
45. Dark current measurements in pressurized SF6: Influence of relative humidity and temperature
- Author
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Olivier Lesaint, Olivier Gallot-Lavallée, L. Zavattoni, and Rachelle Hanna
- Subjects
Chemistry ,Analytical chemistry ,Relative humidity ,Dark current - Published
- 2014
- Full Text
- View/download PDF
46. Positive streamers in short and large gaps in hydrocarbons of various chemical natures
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F. Mc Cluskey, Olivier Lesaint, André Denat, Laboratoire de Génie Electrique de Grenoble (G2ELab), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS), Laboratoire des Écoulements Géophysiques et Industriels [Grenoble] (LEGI), and Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)
- Subjects
business.industry ,Chemistry ,[SPI.NRJ]Engineering Sciences [physics]/Electric power ,Optoelectronics ,business ,Engineering physics ,ComputingMilieux_MISCELLANEOUS - Abstract
International audience
- Published
- 2014
47. Study of streamer inception in cyclohexane with a sensitive charge measurement technique under impulse voltage
- Author
-
Olivier Lesaint, Petru V. Notingher, Nelly Bonifaci, André Denat, and L. Dumitrescu
- Subjects
Cyclohexane ,Chemistry ,System of measurement ,Hydrostatic pressure ,Analytical chemistry ,Liquid phase ,Mechanics ,Impulse (physics) ,Condensed Matter Physics ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,chemistry.chemical_compound ,Dc voltage ,Rise time ,Electrical and Electronic Engineering ,Biotechnology ,Voltage - Abstract
This paper presents an experimental study of streamer initiation in liquid cyclohexane. The aim is to compare specific features of streamer initiation in positive and negative polarity. Experiments are carried out in point-plane geometry under impulse voltage. A new differential charge measurement system is presented. It allows to obtain a high detection sensitivity under impulse voltage (below 0.1 pC). The investigations presented consider the influence of applied voltage, impulse rise time, hydrostatic pressure. As previously observed under DC voltage, negative streamer initiation is due to an avalanche in the liquid phase, and is not affected by pressure, up to 10 MPa. In contrast, the mechanisms leading to positive streamer initiation are not clearly established. In this polarity, an increase of streamer initiation voltage is observed when the pressure is raised.
- Published
- 2001
- Full Text
- View/download PDF
48. On the relationship between streamer branching and propagation in liquids: influence of pyrene in cyclohexane
- Author
-
Olivier Lesaint and M Jung
- Subjects
Acoustics and Ultrasonics ,Cyclohexane ,Chemistry ,business.industry ,High voltage ,Condensed Matter Physics ,Acceleration voltage ,Molecular physics ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Protein filament ,chemistry.chemical_compound ,Optics ,Pyrene ,Breakdown voltage ,Microscopic theory ,business ,Voltage - Abstract
This paper presents an experimental study on the influence of an aromatic additive (pyrene) on the propagation of positive filamentary streamers and breakdown in liquid cyclohexane. Experiments are carried out in point-plane gaps up to 5 cm over a wide voltage range. With pyrene, the propagation is facilitated, and thus the breakdown voltage is lowered in point-plane geometry. Streamers also become very branched, and a much larger number of filaments propagate than in pure cyclohexane. Correlated to this, a large increase of the inception voltage of fast streamers (acceleration voltage) is observed at high voltage. This fact can be explained by macroscopic electrostatic properties of streamers, which depend on their geometrical structure. When more and more filaments propagate at high voltage they shield each other, which in turn limits their tip field (and thus velocity) at a nearly constant value over a large voltage range. The propagation velocity is thus not only determined by microscopic processes at the filament heads. Consequently, it does not always constitute an adequate parameter to directly appreciate and compare microscopic propagation processes. A discussion about streamer mechanisms is also presented.
- Published
- 2000
- Full Text
- View/download PDF
49. Streamer propagation and breakdown under ac voltage in very large oil gaps
- Author
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R. Tobazeon, P. Gournay, Olivier Lesaint, J. Aubin, A. Saker, and M. Mailhot
- Subjects
Materials science ,Condensed matter physics ,Half cycle ,business.industry ,Electric breakdown ,Electrical engineering ,law.invention ,Stress (mechanics) ,law ,Electrode ,Breakdown voltage ,Electrical and Electronic Engineering ,Alternating current ,business ,Voltage - Abstract
This paper presents a study of prebreakdown and breakdown phenomena under ac voltage in mineral oil in very large gaps (/spl les/80 cm). The investigations presented concern the measurement of breakdown voltages together with the recording of streamers in rod-plane and sphere-plane electrode systems, at different gap sizes. A breakdown mode specific to ac voltage is found, in which 'bursts' composed of streamers initiated at each half cycle appear. This mode leads to the lowest breakdown fields recorded under ac. Values of the average stress required for burst or direct breakdown modes are deduced from the experiments. Positive streamers are responsible for breakdown in large gaps: their propagation is easy and does not depend on the gap geometry and on the presence of particles. On the other hand, the propagation of negative streamers is quenched when not very divergent fields are used.
- Published
- 1998
- Full Text
- View/download PDF
50. Positive streamer propagation in large oil gaps: experimental characterization of propagation modes
- Author
-
Olivier Lesaint and G. Massala
- Subjects
business.industry ,Chemistry ,Electric breakdown ,Streak ,Impulse (physics) ,Transient current ,Computational physics ,Optics ,Breakdown voltage ,Light emission ,Electrical measurements ,Electrical and Electronic Engineering ,business ,Voltage - Abstract
This paper presents an experimental study of positive streamer propagation in mineral oil, in large point-plane gaps under impulse voltage. A systematic investigation was done concerning the influence of gap distance (/spl les/35 cm), and voltage from streamer inception up to large overvoltages. The measurements presented concern breakdown voltage measurements, time to breakdown, visualization of streamers (streak and still photographs), electrical measurements (transient current, charge), light emission intensity. Streamers are characterized and then classified into different modes (2nd, 3rd and 4th modes) according to their propagation velocities up to more than 100 km/s. According to the applied voltage, transitions between modes are observed, and correlations are established between charge, shape, and streamer velocity. The physical mechanisms as well as practical consequences are then discussed.
- Published
- 1998
- Full Text
- View/download PDF
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