Pub Date : 1992-10-18DOI: 10.1109/CEIDP.1992.283248
R. Gerhard-Multhaupt, G. Eberle, Xia Zhongfu, Y. Guo-Mao, W. Eisenmenger
Charge spreading in three different types of Teflon electrets was studied by means of piezoelectrically generated pressure steps, FEP and PFA samples corona-charged at room temperature usually exhibited only a surface charge layer. Uniform charge spreading throughout the bulk was found in FEP charged at or heated to high temperatures. Charge spreading was much less prominent in PFA because of a smaller retrapping efficiency. In PTFE (polytetrafluorethylene), charges from the surface and the rear electrode were injected into the bulk during charging at any temperature. Electron-beam-deposited charge layers broadened significantly upon heating.<>
{"title":"Electric-field profiles in corona- or electron-beam-charged and thermally treated Teflon PTFE, FEP, and PFA films","authors":"R. Gerhard-Multhaupt, G. Eberle, Xia Zhongfu, Y. Guo-Mao, W. Eisenmenger","doi":"10.1109/CEIDP.1992.283248","DOIUrl":"https://doi.org/10.1109/CEIDP.1992.283248","url":null,"abstract":"Charge spreading in three different types of Teflon electrets was studied by means of piezoelectrically generated pressure steps, FEP and PFA samples corona-charged at room temperature usually exhibited only a surface charge layer. Uniform charge spreading throughout the bulk was found in FEP charged at or heated to high temperatures. Charge spreading was much less prominent in PFA because of a smaller retrapping efficiency. In PTFE (polytetrafluorethylene), charges from the surface and the rear electrode were injected into the bulk during charging at any temperature. Electron-beam-deposited charge layers broadened significantly upon heating.<<ETX>>","PeriodicalId":370015,"journal":{"name":"[Proceedings] 1992 Annual Report: Conference on Electrical Insulation and Dielectric Phenomena","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124258786","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 : 1992-10-18DOI: 10.1109/CEIDP.1992.283188
A. Dereggi, B. Dickens, C. Laburthe-Tolra, C. Alquié, J. Lewiner
Measurements of the polarization distribution produced in PVC (polyvinyl chloride) by electron-beam irradiation shows that the bimorphic, radiation-induced polarization is very long lived. Measurements on the poling temperature dependence have established the difficulty of poling PVC significantly below its T/sub g/ using an applied field alone. The measurements leave open the possibility that the radiation-induced polarization in PVC is not just a result of the radiation-induced field, but may involve some other radiation effect that facilitates dipole orientation in the glassy state. While it does not seem likely that the response signals could be due to space charge, this possibility cannot be laid to rest until it is shown that the irradiation did not induce inhomogeneous material properties.<>
{"title":"Radiation-induced polarization in polyvinyl chloride revisited","authors":"A. Dereggi, B. Dickens, C. Laburthe-Tolra, C. Alquié, J. Lewiner","doi":"10.1109/CEIDP.1992.283188","DOIUrl":"https://doi.org/10.1109/CEIDP.1992.283188","url":null,"abstract":"Measurements of the polarization distribution produced in PVC (polyvinyl chloride) by electron-beam irradiation shows that the bimorphic, radiation-induced polarization is very long lived. Measurements on the poling temperature dependence have established the difficulty of poling PVC significantly below its T/sub g/ using an applied field alone. The measurements leave open the possibility that the radiation-induced polarization in PVC is not just a result of the radiation-induced field, but may involve some other radiation effect that facilitates dipole orientation in the glassy state. While it does not seem likely that the response signals could be due to space charge, this possibility cannot be laid to rest until it is shown that the irradiation did not induce inhomogeneous material properties.<<ETX>>","PeriodicalId":370015,"journal":{"name":"[Proceedings] 1992 Annual Report: Conference on Electrical Insulation and Dielectric Phenomena","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116992396","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 : 1992-10-18DOI: 10.1109/CEIDP.1992.283150
É. David, J. Fourmigue, J. Parpal, J. Crine
The authors report infrared (IR) absorption measurements conducted on laboratory-aged and unaged cross-linked polyethylene (XLPE) cable samples. Variations in the IR absorbance of the methyl group (1377 cm/sup -1/) and the carbonyl groups ( approximately 1700 cm/sup -1/) were recorded as a function of both radial and angular coordinates for the samples. These variations were found to be strongly correlated with optical birefringence measurements made on the same samples. Morphological parameters and IR absorption differ in regions containing residual stresses compared to unstressed regions, in both aged and unaged cables. It is believed that these variations originate from nonuniform mechanical and thermal stresses during manufacturing.<>
{"title":"Correlation between FTIR spectra and birefringence measurements in XLPE cable insulation","authors":"É. David, J. Fourmigue, J. Parpal, J. Crine","doi":"10.1109/CEIDP.1992.283150","DOIUrl":"https://doi.org/10.1109/CEIDP.1992.283150","url":null,"abstract":"The authors report infrared (IR) absorption measurements conducted on laboratory-aged and unaged cross-linked polyethylene (XLPE) cable samples. Variations in the IR absorbance of the methyl group (1377 cm/sup -1/) and the carbonyl groups ( approximately 1700 cm/sup -1/) were recorded as a function of both radial and angular coordinates for the samples. These variations were found to be strongly correlated with optical birefringence measurements made on the same samples. Morphological parameters and IR absorption differ in regions containing residual stresses compared to unstressed regions, in both aged and unaged cables. It is believed that these variations originate from nonuniform mechanical and thermal stresses during manufacturing.<<ETX>>","PeriodicalId":370015,"journal":{"name":"[Proceedings] 1992 Annual Report: Conference on Electrical Insulation and Dielectric Phenomena","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125125249","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 : 1992-10-18DOI: 10.1109/CEIDP.1992.283172
Y. Kuboyama, I. Takasaki, H. Mitsui, H. Isono, M. Sone
The relationship between micropoints and field emission by a microchannel plate with a luminescent anode is studied. It is shown that the field emission electrons are emitted from the micropoints on the cathode surface. Most of micropoints disappear after emitting an electron, so they cannot keep emitting. The location of micropoints differs with the applied voltage, and they are distributed over the entire surface as the voltage is raised.<>
{"title":"Study of relation between micropoints and field emission by microchannel-plate with luminescent anode","authors":"Y. Kuboyama, I. Takasaki, H. Mitsui, H. Isono, M. Sone","doi":"10.1109/CEIDP.1992.283172","DOIUrl":"https://doi.org/10.1109/CEIDP.1992.283172","url":null,"abstract":"The relationship between micropoints and field emission by a microchannel plate with a luminescent anode is studied. It is shown that the field emission electrons are emitted from the micropoints on the cathode surface. Most of micropoints disappear after emitting an electron, so they cannot keep emitting. The location of micropoints differs with the applied voltage, and they are distributed over the entire surface as the voltage is raised.<<ETX>>","PeriodicalId":370015,"journal":{"name":"[Proceedings] 1992 Annual Report: Conference on Electrical Insulation and Dielectric Phenomena","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122343711","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 : 1992-10-18DOI: 10.1109/CEIDP.1992.283221
J. Thalji, J. K. Nelson
An apparatus for the assessment of charge deposited in gaseous surface discharges has been designed and tested. It can provide a fresh surface for each test and permits a scan of surface charges seated (or deposited) along the interface. In this way several hundred fresh surfaces can be tested without dismantling the gas enclosure. Experimental results are presented for a case study example.<>
{"title":"An apparatus for the assessment of charge deposited in gaseous surface discharges","authors":"J. Thalji, J. K. Nelson","doi":"10.1109/CEIDP.1992.283221","DOIUrl":"https://doi.org/10.1109/CEIDP.1992.283221","url":null,"abstract":"An apparatus for the assessment of charge deposited in gaseous surface discharges has been designed and tested. It can provide a fresh surface for each test and permits a scan of surface charges seated (or deposited) along the interface. In this way several hundred fresh surfaces can be tested without dismantling the gas enclosure. Experimental results are presented for a case study example.<<ETX>>","PeriodicalId":370015,"journal":{"name":"[Proceedings] 1992 Annual Report: Conference on Electrical Insulation and Dielectric Phenomena","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128763756","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 : 1992-10-18DOI: 10.1109/CEIDP.1992.283155
J. Bezille, H. Janah, J. Chan, M. Hartley
It was shown previously that low-molecular-weight fractions of copolymers used in semiconductive compounds diffuse into the insulation during the cable manufacturing process. In the present work, the influence of this diffusion on electrical properties such as AC, DC, and impulse strength has been studied. Initial tests on thin cross-linked polyethylene films peeled from full-size cables have shown different trends. Interfacial diffusion has a detrimental effect on DC strength, but its effect on AC and impulse strength is not clear.<>
{"title":"Influence of diffusion on some electrical properties of synthetic cables","authors":"J. Bezille, H. Janah, J. Chan, M. Hartley","doi":"10.1109/CEIDP.1992.283155","DOIUrl":"https://doi.org/10.1109/CEIDP.1992.283155","url":null,"abstract":"It was shown previously that low-molecular-weight fractions of copolymers used in semiconductive compounds diffuse into the insulation during the cable manufacturing process. In the present work, the influence of this diffusion on electrical properties such as AC, DC, and impulse strength has been studied. Initial tests on thin cross-linked polyethylene films peeled from full-size cables have shown different trends. Interfacial diffusion has a detrimental effect on DC strength, but its effect on AC and impulse strength is not clear.<<ETX>>","PeriodicalId":370015,"journal":{"name":"[Proceedings] 1992 Annual Report: Conference on Electrical Insulation and Dielectric Phenomena","volume":"94 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123847484","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 : 1992-10-18DOI: 10.1109/CEIDP.1992.283201
M. B. Srinivas, T. Ramu
Proposes a novel empirical multifactor stress model which involves an additional mechanical (vibrational or fatigue) stress. The model is based on data obtained on epoxy-mica-insulated high-voltage generator coils. The possible degradation mechanisms under combined stress are discussed, highlighting those under fatigue stress based on Miner's cumulative damage concept. It is concluded that the empirical model presented here can be employed to estimate the insulation life under service conditions with a reasonable degree of accuracy.<>
{"title":"Multistress aging of epoxy-mica insulation system","authors":"M. B. Srinivas, T. Ramu","doi":"10.1109/CEIDP.1992.283201","DOIUrl":"https://doi.org/10.1109/CEIDP.1992.283201","url":null,"abstract":"Proposes a novel empirical multifactor stress model which involves an additional mechanical (vibrational or fatigue) stress. The model is based on data obtained on epoxy-mica-insulated high-voltage generator coils. The possible degradation mechanisms under combined stress are discussed, highlighting those under fatigue stress based on Miner's cumulative damage concept. It is concluded that the empirical model presented here can be employed to estimate the insulation life under service conditions with a reasonable degree of accuracy.<<ETX>>","PeriodicalId":370015,"journal":{"name":"[Proceedings] 1992 Annual Report: Conference on Electrical Insulation and Dielectric Phenomena","volume":"59 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121612654","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 : 1992-10-18DOI: 10.1109/CEIDP.1992.283178
P.K. Poovamma, R. Jagadish, K. Dwarakanath
Many failures in large forced-oil-cooled power transformers have been specifically attributed to static electrification, due to the flow of insulating oil. For this reason detailed investigations of some of the important parameters, such as flow rate, moisture content, temperature, extent of aging, and presence of copper, affecting the charging tendency of the oil have been carried out by employing a ministatic tester and a spinning disk system with paraffinic based oil. It is observed that the aforementioned parameters significantly influence the charging tendency of the oil.<>
{"title":"Charging tendency in transformer oil","authors":"P.K. Poovamma, R. Jagadish, K. Dwarakanath","doi":"10.1109/CEIDP.1992.283178","DOIUrl":"https://doi.org/10.1109/CEIDP.1992.283178","url":null,"abstract":"Many failures in large forced-oil-cooled power transformers have been specifically attributed to static electrification, due to the flow of insulating oil. For this reason detailed investigations of some of the important parameters, such as flow rate, moisture content, temperature, extent of aging, and presence of copper, affecting the charging tendency of the oil have been carried out by employing a ministatic tester and a spinning disk system with paraffinic based oil. It is observed that the aforementioned parameters significantly influence the charging tendency of the oil.<<ETX>>","PeriodicalId":370015,"journal":{"name":"[Proceedings] 1992 Annual Report: Conference on Electrical Insulation and Dielectric Phenomena","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114771389","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 : 1992-10-18DOI: 10.1109/CEIDP.1992.283127
M. Kannan, S. Narayandass, C. Balasubramanian, D. Mangalaraj
The electrical conduction properties of thermally deposited neodymium fluoride thin films have been investigated. Al-NdF/sub 3/-Al film capacitors were prepared using a conventional vacuum coating unit on well-cleaned glass substrates. The capacitors attained stability in 45 days of aging or when subjected to three cycles of annealing treatment. The mechanism responsible for the AC conduction was found to be ionic hopping. The occurrence of saturation of conductance at higher frequencies is attributed to dipolar relaxation in the film structure. The DC conduction in these films was observed to be of Schottky type. The existence of exponential trap distribution was confirmed and the trap density was found to be 5.108*10/sup 33/ m/sup -3/.<>
{"title":"Aging, annealing, and conduction studies on vacuum deposited NdF/sub 3/ thin films","authors":"M. Kannan, S. Narayandass, C. Balasubramanian, D. Mangalaraj","doi":"10.1109/CEIDP.1992.283127","DOIUrl":"https://doi.org/10.1109/CEIDP.1992.283127","url":null,"abstract":"The electrical conduction properties of thermally deposited neodymium fluoride thin films have been investigated. Al-NdF/sub 3/-Al film capacitors were prepared using a conventional vacuum coating unit on well-cleaned glass substrates. The capacitors attained stability in 45 days of aging or when subjected to three cycles of annealing treatment. The mechanism responsible for the AC conduction was found to be ionic hopping. The occurrence of saturation of conductance at higher frequencies is attributed to dipolar relaxation in the film structure. The DC conduction in these films was observed to be of Schottky type. The existence of exponential trap distribution was confirmed and the trap density was found to be 5.108*10/sup 33/ m/sup -3/.<<ETX>>","PeriodicalId":370015,"journal":{"name":"[Proceedings] 1992 Annual Report: Conference on Electrical Insulation and Dielectric Phenomena","volume":"71 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115902850","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 : 1992-10-18DOI: 10.1109/CEIDP.1992.283231
J. S. Al-Najmawi, O. Farish, R. Fouracre
An attempt is made to elucidate the mechanisms causing charge accumulation on and inside insulating spacers. The experiments were conducted inside a glass cruciform vessel which could be evacuated to 10/sup -2/ torr and had a maximum SF/sub 6/ working pressure of 2 bar. Cylindrical spacers of polytetrafluorethylene and polyethylene (diameter 20 mm, height 10 mm) were investigated. The charge accumulation on smooth-surfaced insulators was controlled by three mechanisms: dielectric polarization producing heterocharge, surface charge injection from the electrode, and bulk injection from the electrode. The charge accumulated was of the same polarity as the applied voltage. The rough-surfaced insulator produced charge distributions which had charge densities higher than those of the comparable smooth-surfaced insulator.<>
{"title":"Charging mechanisms of polymer spacers electrically stressed in SF/sub 6/ environment","authors":"J. S. Al-Najmawi, O. Farish, R. Fouracre","doi":"10.1109/CEIDP.1992.283231","DOIUrl":"https://doi.org/10.1109/CEIDP.1992.283231","url":null,"abstract":"An attempt is made to elucidate the mechanisms causing charge accumulation on and inside insulating spacers. The experiments were conducted inside a glass cruciform vessel which could be evacuated to 10/sup -2/ torr and had a maximum SF/sub 6/ working pressure of 2 bar. Cylindrical spacers of polytetrafluorethylene and polyethylene (diameter 20 mm, height 10 mm) were investigated. The charge accumulation on smooth-surfaced insulators was controlled by three mechanisms: dielectric polarization producing heterocharge, surface charge injection from the electrode, and bulk injection from the electrode. The charge accumulated was of the same polarity as the applied voltage. The rough-surfaced insulator produced charge distributions which had charge densities higher than those of the comparable smooth-surfaced insulator.<<ETX>>","PeriodicalId":370015,"journal":{"name":"[Proceedings] 1992 Annual Report: Conference on Electrical Insulation and Dielectric Phenomena","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131376033","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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