Pub Date : 1990-09-10DOI: 10.1109/ICDL.1990.202949
V.F. Klimkin
A six-frame high-speed laser schlieren system which has variable intervals from frame to frame has been developed. A ruby laser with a pulse duration of 5 ns is used as the light source. By means of this system, one can obtain a sequence of six schlieren pictures of an electrical discharge with one shot of the main laser. A time delay between two diagnostic pulses is 5-50 ns and can easily be changed. The applicability of the system is demonstrated for rapidly changing prebreakdown processes in liquid dielectrics in the nanosecond region.<>
{"title":"Multiframe high-speed laser schlieren system for observations of prebreakdown phenomena in liquids in nanosecond region","authors":"V.F. Klimkin","doi":"10.1109/ICDL.1990.202949","DOIUrl":"https://doi.org/10.1109/ICDL.1990.202949","url":null,"abstract":"A six-frame high-speed laser schlieren system which has variable intervals from frame to frame has been developed. A ruby laser with a pulse duration of 5 ns is used as the light source. By means of this system, one can obtain a sequence of six schlieren pictures of an electrical discharge with one shot of the main laser. A time delay between two diagnostic pulses is 5-50 ns and can easily be changed. The applicability of the system is demonstrated for rapidly changing prebreakdown processes in liquid dielectrics in the nanosecond region.<<ETX>>","PeriodicalId":193137,"journal":{"name":"10th International Conference on Conduction and Breakdown in Dielectric Liquids","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129740438","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1990-09-10DOI: 10.1109/ICDL.1990.202858
A. Belevtsev
The author considers novel analytical methods in the theory of electron transport in electric fields in liquid rare gases. They are developed both for stationary and nonstationary conditions and are based on the exact analytical solutions of the kinetic Boltzman equation for electrons in dense matter consisting of spatially correlated heavy scatterers, taking into account elastic and inelastic collisions of electrons with the liquid particles. Electric fields under consideration may be time-independent or variable.<>
{"title":"Theoretical study of electron transport in nonpolar liquids","authors":"A. Belevtsev","doi":"10.1109/ICDL.1990.202858","DOIUrl":"https://doi.org/10.1109/ICDL.1990.202858","url":null,"abstract":"The author considers novel analytical methods in the theory of electron transport in electric fields in liquid rare gases. They are developed both for stationary and nonstationary conditions and are based on the exact analytical solutions of the kinetic Boltzman equation for electrons in dense matter consisting of spatially correlated heavy scatterers, taking into account elastic and inelastic collisions of electrons with the liquid particles. Electric fields under consideration may be time-independent or variable.<<ETX>>","PeriodicalId":193137,"journal":{"name":"10th International Conference on Conduction and Breakdown in Dielectric Liquids","volume":"187 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129781835","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1990-09-10DOI: 10.1109/ICDL.1990.202934
H. Yamada, T. Murakami, K. Kusano, T. Sato
Electrical breakdown phenomena in cyclohexane for a point-to-plane gap configuration have been investigated using an image converter camera and a photooptical current measuring technique. Camera records for 4-mm gap spacing show that the sonic and supersonic propagating velocities of the positive streamer in the liquid are 1.3 km/s and 2.8 km/s, respectively. Time-to-breakdown for gap spacings of less than 1 mm was directly measured from prebreakdown current. Two linear relations to the time lag and gap spacing are obtained, which indicates two constant propagation velocities: 0.18 km/s (subsonic) and 1.3 km/s.<>
{"title":"Positive streamer propagation and breakdown time lag in cyclohexane under micro-second rectangular pulse voltage","authors":"H. Yamada, T. Murakami, K. Kusano, T. Sato","doi":"10.1109/ICDL.1990.202934","DOIUrl":"https://doi.org/10.1109/ICDL.1990.202934","url":null,"abstract":"Electrical breakdown phenomena in cyclohexane for a point-to-plane gap configuration have been investigated using an image converter camera and a photooptical current measuring technique. Camera records for 4-mm gap spacing show that the sonic and supersonic propagating velocities of the positive streamer in the liquid are 1.3 km/s and 2.8 km/s, respectively. Time-to-breakdown for gap spacings of less than 1 mm was directly measured from prebreakdown current. Two linear relations to the time lag and gap spacing are obtained, which indicates two constant propagation velocities: 0.18 km/s (subsonic) and 1.3 km/s.<<ETX>>","PeriodicalId":193137,"journal":{"name":"10th International Conference on Conduction and Breakdown in Dielectric Liquids","volume":"80 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122250808","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1990-09-10DOI: 10.1109/ICDL.1990.202887
D.H. Ren, A. Watson
Above a specific threshold coordinate on the V-I characteristic, prebreakdown conduction current flows through transformer oil in direct proportion to a simple power of the applied voltage when this rises and falls linearly in time. The threshold coordinate for this power law regime as well as the power law exponent has been shown to be dependent on the electrode geometry, gap separation, and electrode material for dimethyl siloxane, but transformer oil exhibits in addition a sensitivity to the value of the maximum stress value per cycle. At high maximum stress the characteristic V-I loop is seen to divide into two, and above the turnover point V/sub th/ behaves differently with respect to the ramp rate than below it. This phenomenon is described in its relationship to gap separation and electrode material and compared with similar data observed with dimethyl siloxane.<>
{"title":"Characteristics of the threshold coordinate for high stress conduction in transformer fluid","authors":"D.H. Ren, A. Watson","doi":"10.1109/ICDL.1990.202887","DOIUrl":"https://doi.org/10.1109/ICDL.1990.202887","url":null,"abstract":"Above a specific threshold coordinate on the V-I characteristic, prebreakdown conduction current flows through transformer oil in direct proportion to a simple power of the applied voltage when this rises and falls linearly in time. The threshold coordinate for this power law regime as well as the power law exponent has been shown to be dependent on the electrode geometry, gap separation, and electrode material for dimethyl siloxane, but transformer oil exhibits in addition a sensitivity to the value of the maximum stress value per cycle. At high maximum stress the characteristic V-I loop is seen to divide into two, and above the turnover point V/sub th/ behaves differently with respect to the ramp rate than below it. This phenomenon is described in its relationship to gap separation and electrode material and compared with similar data observed with dimethyl siloxane.<<ETX>>","PeriodicalId":193137,"journal":{"name":"10th International Conference on Conduction and Breakdown in Dielectric Liquids","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121594944","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1990-09-10DOI: 10.1109/ICDL.1990.202916
J. Chang, F. Tran
The electrohydrodynamically enhanced natural convection of dielectric liquids in a horizontally cylindrical annulus was numerically investigated under DC and pulsed applied electric field conditions over the range of Rayleigh number from 10/sup 4/ to 2*10/sup 4/, the Prandtl number from 5 to 7, and the electric Rayleigh number from 0 to 2*10/sup 3/ for the inner-to-outer radius ratio of 2. Simulation results show that the applied, radial, DC electric field always enhances the heat transfer by natural convection process. The velocity and heat transfer enhancement are from a factor of 2 to 20 and from 10% to 30%, respectively, for EI varying from 5*10/sup 2/ to 2*10/sup 3/.<>
{"title":"Numerical simulation of electrohydrodynamically enhanced natural convection heat transfer of dielectric liquid in a horizontal annulus","authors":"J. Chang, F. Tran","doi":"10.1109/ICDL.1990.202916","DOIUrl":"https://doi.org/10.1109/ICDL.1990.202916","url":null,"abstract":"The electrohydrodynamically enhanced natural convection of dielectric liquids in a horizontally cylindrical annulus was numerically investigated under DC and pulsed applied electric field conditions over the range of Rayleigh number from 10/sup 4/ to 2*10/sup 4/, the Prandtl number from 5 to 7, and the electric Rayleigh number from 0 to 2*10/sup 3/ for the inner-to-outer radius ratio of 2. Simulation results show that the applied, radial, DC electric field always enhances the heat transfer by natural convection process. The velocity and heat transfer enhancement are from a factor of 2 to 20 and from 10% to 30%, respectively, for EI varying from 5*10/sup 2/ to 2*10/sup 3/.<<ETX>>","PeriodicalId":193137,"journal":{"name":"10th International Conference on Conduction and Breakdown in Dielectric Liquids","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134147950","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1990-09-10DOI: 10.1109/ICDL.1990.202966
A. Zaky, I. Megahed, M. El-Awa
The effect of forced flow velocity on the breakdown voltage/gap length characteristics of transformer oil was studied using a needle point and a mesh plane electrode system. The velocity of the axial (co-field) oil flow varied from 0 to 280 cm/s. Tests were carried out on degassed oil, O/sub 2/-saturated oil, and SF/sub 6/-saturated oil for negative and positive point polarities. For degassed oil there was a large increase in the breakdown voltage with increasing oil velocity for both polarities of the point and over the whole range of gaps examined. For O/sub 2/- and SF/sub 6/-saturated oils a similar increase in breakdown voltage was observed only with the point negative. With the point positive, velocities above 90 cm/s had no effect.<>
{"title":"Effect of liquid flow velocity on the breakdown voltage of mineral oil under highly nonuniform fields","authors":"A. Zaky, I. Megahed, M. El-Awa","doi":"10.1109/ICDL.1990.202966","DOIUrl":"https://doi.org/10.1109/ICDL.1990.202966","url":null,"abstract":"The effect of forced flow velocity on the breakdown voltage/gap length characteristics of transformer oil was studied using a needle point and a mesh plane electrode system. The velocity of the axial (co-field) oil flow varied from 0 to 280 cm/s. Tests were carried out on degassed oil, O/sub 2/-saturated oil, and SF/sub 6/-saturated oil for negative and positive point polarities. For degassed oil there was a large increase in the breakdown voltage with increasing oil velocity for both polarities of the point and over the whole range of gaps examined. For O/sub 2/- and SF/sub 6/-saturated oils a similar increase in breakdown voltage was observed only with the point negative. With the point positive, velocities above 90 cm/s had no effect.<<ETX>>","PeriodicalId":193137,"journal":{"name":"10th International Conference on Conduction and Breakdown in Dielectric Liquids","volume":"36 12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125726392","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1990-09-10DOI: 10.1109/ICDL.1990.202897
M. Sone, H. Mitsui, N. Iijima, S. Itabashi, A. Ebe, K. Takaoka
Infrared spectroscopy is used to study the fine structure of water in liquid dielectrics. It is shown that the near-infrared technique can define the states of water as free water, cluster water, and hydrogen-bound water. Furthermore, the infrared technique can identify the monomer, dimer, trimer, and polymer states of water. It is also found that the size of the water cluster can influence the electrical properties. Results are presented for benzene and alkyl benzene.<>
{"title":"States of dissolved water in liquid dielectrics","authors":"M. Sone, H. Mitsui, N. Iijima, S. Itabashi, A. Ebe, K. Takaoka","doi":"10.1109/ICDL.1990.202897","DOIUrl":"https://doi.org/10.1109/ICDL.1990.202897","url":null,"abstract":"Infrared spectroscopy is used to study the fine structure of water in liquid dielectrics. It is shown that the near-infrared technique can define the states of water as free water, cluster water, and hydrogen-bound water. Furthermore, the infrared technique can identify the monomer, dimer, trimer, and polymer states of water. It is also found that the size of the water cluster can influence the electrical properties. Results are presented for benzene and alkyl benzene.<<ETX>>","PeriodicalId":193137,"journal":{"name":"10th International Conference on Conduction and Breakdown in Dielectric Liquids","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127623730","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1990-09-10DOI: 10.1109/ICDL.1990.202927
N. Bonfaci, A. Denat
In a previous study of electrical conduction phenomena in cyclohexane with point-plane electrode geometry, specific conduction regimes were observed as a function of point radius and voltage polarity. In the present work, an analysis is made of the characteristics of light emission (size of the luminous zone, spectral analysis, etc.) of these conduction regimes in nonpolar liquids of different electron mobility, K/sub e/, as a function of hydrostatic pressure, point radius, etc. A similar investigation was carried out on the gaseous hydrocarbons (methane, propane, etc.) as a function of the density. Experimental results, which show a relationship between K/sub e/ and the characteristics of conduction regimes, indicate that hot electron mechanisms have a considerable effect on conduction phenomena in purified nonpolar liquids.<>
{"title":"Spectral analysis of the light emitted by prebreakdown phenomena in liquid and gaseous nonpolar fluids","authors":"N. Bonfaci, A. Denat","doi":"10.1109/ICDL.1990.202927","DOIUrl":"https://doi.org/10.1109/ICDL.1990.202927","url":null,"abstract":"In a previous study of electrical conduction phenomena in cyclohexane with point-plane electrode geometry, specific conduction regimes were observed as a function of point radius and voltage polarity. In the present work, an analysis is made of the characteristics of light emission (size of the luminous zone, spectral analysis, etc.) of these conduction regimes in nonpolar liquids of different electron mobility, K/sub e/, as a function of hydrostatic pressure, point radius, etc. A similar investigation was carried out on the gaseous hydrocarbons (methane, propane, etc.) as a function of the density. Experimental results, which show a relationship between K/sub e/ and the characteristics of conduction regimes, indicate that hot electron mechanisms have a considerable effect on conduction phenomena in purified nonpolar liquids.<<ETX>>","PeriodicalId":193137,"journal":{"name":"10th International Conference on Conduction and Breakdown in Dielectric Liquids","volume":"414 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133470935","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1990-09-10DOI: 10.1109/ICDL.1990.202851
P. Watson
Optical studies of prebreakdown events in insulating liquids make it possible to identify several stages in the breakdown of negative point-plane gaps, starting with the creation of a rapidly expanding vapor cavity adjacent to the point electrode. As it expands the surface of this cavity becomes unstable and the growth of an electrohydrodynamic instability is observed; the runaway growth of this instability leads to streamers that bridge the gap and cause the actual breakdown. By combining simple electrostatic and hydrodynamic concepts one can derive equations for cavity growth, instability growth rate, and streamer velocity that are in reasonable agreement with experiment.<>
{"title":"The role of electrostatic and hydrodynamic forces in the electrical breakdown of liquid dielectrics","authors":"P. Watson","doi":"10.1109/ICDL.1990.202851","DOIUrl":"https://doi.org/10.1109/ICDL.1990.202851","url":null,"abstract":"Optical studies of prebreakdown events in insulating liquids make it possible to identify several stages in the breakdown of negative point-plane gaps, starting with the creation of a rapidly expanding vapor cavity adjacent to the point electrode. As it expands the surface of this cavity becomes unstable and the growth of an electrohydrodynamic instability is observed; the runaway growth of this instability leads to streamers that bridge the gap and cause the actual breakdown. By combining simple electrostatic and hydrodynamic concepts one can derive equations for cavity growth, instability growth rate, and streamer velocity that are in reasonable agreement with experiment.<<ETX>>","PeriodicalId":193137,"journal":{"name":"10th International Conference on Conduction and Breakdown in Dielectric Liquids","volume":"34 6","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131589154","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1990-09-10DOI: 10.1109/ICDL.1990.202860
J. Lopez‐Castillo, Y. Frongillo, B. Plenkiewicz, J. Jay-Gerin
Path-integral molecular-dynamics simulations are used to calculate the energy V/sub 0/ of excess electrons in liquid argon at various densities in the gas-phase region. Using the same electron-argon interaction potential, V/sub 0/ is also calculated within the framework of the Wigner-Seitz model. Both calculations agree with experiment. The excess electron is found to be delocalized over about a thousand atoms, which could explain why the Wigner-Seitz mean-field calculation agrees so well with the measured data.<>
{"title":"Path-integral molecular-dynamics calculation of the conduction-band energy of excess electrons in fluid argon","authors":"J. Lopez‐Castillo, Y. Frongillo, B. Plenkiewicz, J. Jay-Gerin","doi":"10.1109/ICDL.1990.202860","DOIUrl":"https://doi.org/10.1109/ICDL.1990.202860","url":null,"abstract":"Path-integral molecular-dynamics simulations are used to calculate the energy V/sub 0/ of excess electrons in liquid argon at various densities in the gas-phase region. Using the same electron-argon interaction potential, V/sub 0/ is also calculated within the framework of the Wigner-Seitz model. Both calculations agree with experiment. The excess electron is found to be delocalized over about a thousand atoms, which could explain why the Wigner-Seitz mean-field calculation agrees so well with the measured data.<<ETX>>","PeriodicalId":193137,"journal":{"name":"10th International Conference on Conduction and Breakdown in Dielectric Liquids","volume":"167 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1990-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115937494","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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