To obtain a waterstop in the longitudinal direction of a three-phase belted cable, a thin nonwoven tape was applied to the core insulation and to the interstices between the belt insulation and the core insulation. As these tapes are very poor dielectrics with low breakdown stress, it was expected that the breakdown tests would be impaired. On the contrary, the life expectancy was raised from less than 10 years to more than 30 years at 10 kV. Further study revealed that this dielectric improvement was caused by a considerable reduction of the discharges in the interstices of the cable; reductions of several hundred times were measured. The fibers at the air-dielectric interface appear to act as barriers for the surface discharges.<>
{"title":"Discharge phenomena in voids filled with fibrous materials","authors":"P. Morshuis, F. H. Kreuger","doi":"10.1109/ICSD.1989.69172","DOIUrl":"https://doi.org/10.1109/ICSD.1989.69172","url":null,"abstract":"To obtain a waterstop in the longitudinal direction of a three-phase belted cable, a thin nonwoven tape was applied to the core insulation and to the interstices between the belt insulation and the core insulation. As these tapes are very poor dielectrics with low breakdown stress, it was expected that the breakdown tests would be impaired. On the contrary, the life expectancy was raised from less than 10 years to more than 30 years at 10 kV. Further study revealed that this dielectric improvement was caused by a considerable reduction of the discharges in the interstices of the cable; reductions of several hundred times were measured. The fibers at the air-dielectric interface appear to act as barriers for the surface discharges.<<ETX>>","PeriodicalId":184126,"journal":{"name":"Proceedings of the 3rd International Conference on Conduction and Breakdown in Solid Dielectrics","volume":"52 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124948214","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}
T. Nakano, M. Fukuyama, H. Hayashi, K. Ishii, Y. Ohki
It has been suggested that when dielectric breakdown is caused by an electronic process, the scattering of electrons will increase the dielectric strength. To confirm this, polar groups were introduced into plasma-polymer films, assuming that the polar groups would act as scattering centers, and the dielectric strength was measured. It was found that when the breakdown process is electronic, the breakdown field increases due to the introduction of an appropriate number of electron scattering centers such as nitrogen and fluorine.<>
{"title":"Electronic breakdown process of plasma polymer films","authors":"T. Nakano, M. Fukuyama, H. Hayashi, K. Ishii, Y. Ohki","doi":"10.1109/ICSD.1989.69166","DOIUrl":"https://doi.org/10.1109/ICSD.1989.69166","url":null,"abstract":"It has been suggested that when dielectric breakdown is caused by an electronic process, the scattering of electrons will increase the dielectric strength. To confirm this, polar groups were introduced into plasma-polymer films, assuming that the polar groups would act as scattering centers, and the dielectric strength was measured. It was found that when the breakdown process is electronic, the breakdown field increases due to the introduction of an appropriate number of electron scattering centers such as nitrogen and fluorine.<<ETX>>","PeriodicalId":184126,"journal":{"name":"Proceedings of the 3rd International Conference on Conduction and Breakdown in Solid Dielectrics","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121966847","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}
The relationship between breakdown modeling and the phenomenology of breakdown are elucidated. This phenomenology is based mostly on studies of electric breakdown in thick specimens (1 mm to 25 mm) of both polymeric and nonpolymeric materials, in a macroscopically uniform field geometry. Each specimen was subjected to a single impulse, with breakdown occurring typically on the rise. Risetimes to breakdown were 10 to 30 ns, depending on thickness and rate of rise. Diagnostics included waveforms (specimen voltage, current, and intensity of the self-luminosity), photographs of breakdown configurations from their self-luminosity, and post mortem microscopic studies of damage to the dielectrics and the electrodes. Breakdown initiation and tree propagation are treated. Some generalizations on breakdown modeling are presented. The need for a dynamical model that incorporates the macroscopic geometry, presence of the key microscopic field enhancement site, realistic parameters for high-field conduction processes, initial conditions on space charge distribution, the time history of the applied stresses, and three-dimensional time-dependent solutions is emphasized.<>
{"title":"Toward developing a dynamic theory of electric breakdown in solids","authors":"P. Budenstein","doi":"10.1109/ICSD.1989.69253","DOIUrl":"https://doi.org/10.1109/ICSD.1989.69253","url":null,"abstract":"The relationship between breakdown modeling and the phenomenology of breakdown are elucidated. This phenomenology is based mostly on studies of electric breakdown in thick specimens (1 mm to 25 mm) of both polymeric and nonpolymeric materials, in a macroscopically uniform field geometry. Each specimen was subjected to a single impulse, with breakdown occurring typically on the rise. Risetimes to breakdown were 10 to 30 ns, depending on thickness and rate of rise. Diagnostics included waveforms (specimen voltage, current, and intensity of the self-luminosity), photographs of breakdown configurations from their self-luminosity, and post mortem microscopic studies of damage to the dielectrics and the electrodes. Breakdown initiation and tree propagation are treated. Some generalizations on breakdown modeling are presented. The need for a dynamical model that incorporates the macroscopic geometry, presence of the key microscopic field enhancement site, realistic parameters for high-field conduction processes, initial conditions on space charge distribution, the time history of the applied stresses, and three-dimensional time-dependent solutions is emphasized.<<ETX>>","PeriodicalId":184126,"journal":{"name":"Proceedings of the 3rd International Conference on Conduction and Breakdown in Solid Dielectrics","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124095046","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}
The principles underlying the use of the acoustic probe and electrostriction methods for the nondestructive measurement of the volume distribution of the electric field intensity and charge density in solids are discussed. Acoustic probing consists of recording an electric signal generated by a charge or polarized sample under the action of a mechanical pulse causing a compression wave. The electrostriction method is based on recording an acoustic signal in the surface of an electrified sample which is affected by an electric pulse. Analysis shows that the two methods are equivalent as regards their physical basis and information provided. The fields of application of these two methods are shown to be somewhat different. Acoustic probing is more correct and technically simple when high-ohmic materials with a long charge relaxation time are under investigation. As an example, the study of diffusion in the nitric-acid-polyethylene system is considered.<>
{"title":"Diagnostics of the volume distribution of conductivity in solids by electroacoustic methods","authors":"A. G. Rozno, V. Gromov, A. S. Lukhin, A. Romanov","doi":"10.1109/ICSD.1989.69260","DOIUrl":"https://doi.org/10.1109/ICSD.1989.69260","url":null,"abstract":"The principles underlying the use of the acoustic probe and electrostriction methods for the nondestructive measurement of the volume distribution of the electric field intensity and charge density in solids are discussed. Acoustic probing consists of recording an electric signal generated by a charge or polarized sample under the action of a mechanical pulse causing a compression wave. The electrostriction method is based on recording an acoustic signal in the surface of an electrified sample which is affected by an electric pulse. Analysis shows that the two methods are equivalent as regards their physical basis and information provided. The fields of application of these two methods are shown to be somewhat different. Acoustic probing is more correct and technically simple when high-ohmic materials with a long charge relaxation time are under investigation. As an example, the study of diffusion in the nitric-acid-polyethylene system is considered.<<ETX>>","PeriodicalId":184126,"journal":{"name":"Proceedings of the 3rd International Conference on Conduction and Breakdown in Solid Dielectrics","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129596972","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}
A novel experimental setup for directly measuring charge carrier injection and space charge buildup in a needle-plane arrangement under high AC fields is presented. Temperature, frequency, voltage, radius of needle tip, electrode gap, and material of the samples can be varied. First results for semicrystalline polymers reveal the occurrence of charge injection at a distinct field strength, an inception field strength of negative charge carriers that is lower than that of positive ones, and a characteristic change in storage behavior at about 500 Hz.<>
{"title":"Space charge phenomena in partially crystalline polymers: on-line measurement of charge carrier motion under high AC-field stress","authors":"G. Krause, S. Gottlich, K. Moller, D. Meurer","doi":"10.1109/ICSD.1989.69259","DOIUrl":"https://doi.org/10.1109/ICSD.1989.69259","url":null,"abstract":"A novel experimental setup for directly measuring charge carrier injection and space charge buildup in a needle-plane arrangement under high AC fields is presented. Temperature, frequency, voltage, radius of needle tip, electrode gap, and material of the samples can be varied. First results for semicrystalline polymers reveal the occurrence of charge injection at a distinct field strength, an inception field strength of negative charge carriers that is lower than that of positive ones, and a characteristic change in storage behavior at about 500 Hz.<<ETX>>","PeriodicalId":184126,"journal":{"name":"Proceedings of the 3rd International Conference on Conduction and Breakdown in Solid Dielectrics","volume":"54 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133834230","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}
The author studied the influence of the length of the conducting particle of the filler on the electrical conductivity of the composites obtained by embedding into polyester polymer needlelike conducting crystals of quinoline salt of tetracyanoquinodimethane. The results clearly demonstrated the importance of shape factors for the formation of a conducting network and percolative charge transport in composite systems. The results are in agreement with the previous data, which have shown that very low values of threshold contents of conducting fillers are observed for large particle-length-to-diameter ratios. Other results confirmed the assumption that the decrease of electrical conductivity of samples after the critical field is exceeded is caused by breaks of the conduction network at the weak points, and that the electrical conduction of low-conduction samples is probably dominated by injection of charge carriers, fluctuation-induced tunneling, and prebreakdown effects.<>
{"title":"The electrical conductivity and breakdown phenomena in polyester polymer-quinoline salt of tetracyanoquinodimethane composites","authors":"A. Kuczkowski","doi":"10.1109/ICSD.1989.69180","DOIUrl":"https://doi.org/10.1109/ICSD.1989.69180","url":null,"abstract":"The author studied the influence of the length of the conducting particle of the filler on the electrical conductivity of the composites obtained by embedding into polyester polymer needlelike conducting crystals of quinoline salt of tetracyanoquinodimethane. The results clearly demonstrated the importance of shape factors for the formation of a conducting network and percolative charge transport in composite systems. The results are in agreement with the previous data, which have shown that very low values of threshold contents of conducting fillers are observed for large particle-length-to-diameter ratios. Other results confirmed the assumption that the decrease of electrical conductivity of samples after the critical field is exceeded is caused by breaks of the conduction network at the weak points, and that the electrical conduction of low-conduction samples is probably dominated by injection of charge carriers, fluctuation-induced tunneling, and prebreakdown effects.<<ETX>>","PeriodicalId":184126,"journal":{"name":"Proceedings of the 3rd International Conference on Conduction and Breakdown in Solid Dielectrics","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125790053","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}
An effort was made to determine factors influencing initiation and growth of vented water trees and to study the reduction of breakdown strength caused by water treeing. Water treeing experiments were performed on both cable samples and Rogowski-type test objects. The influence of aging time and electric field stress was elucidated. In order to test the hypothesis that water treeing basically is a mechanical damage phenomenon connected with environmental stress cracking (ESC), the authors performed water tree experiments with stress-cracking active agents added to the water. It is shown that initiation of vented water trees is considerably enhanced by the presence of the agents.<>
{"title":"Water treeing and breakdown strength reduction of XLPE insulation","authors":"E. Ildstad, J. Sletbak, H. Faremo","doi":"10.1109/ICSD.1989.69248","DOIUrl":"https://doi.org/10.1109/ICSD.1989.69248","url":null,"abstract":"An effort was made to determine factors influencing initiation and growth of vented water trees and to study the reduction of breakdown strength caused by water treeing. Water treeing experiments were performed on both cable samples and Rogowski-type test objects. The influence of aging time and electric field stress was elucidated. In order to test the hypothesis that water treeing basically is a mechanical damage phenomenon connected with environmental stress cracking (ESC), the authors performed water tree experiments with stress-cracking active agents added to the water. It is shown that initiation of vented water trees is considerably enhanced by the presence of the agents.<<ETX>>","PeriodicalId":184126,"journal":{"name":"Proceedings of the 3rd International Conference on Conduction and Breakdown in Solid Dielectrics","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116794655","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}
A computerized TSC (thermally stimulated current) measurement and data analysis system is described. The computer not only eliminates the X-Y recorder, but also allows data averaging, data storage, comparison with other data, and data processing for a variety of purposes. Computerization makes the data as reproducible as possible, speeds up data processing, provides accurate analysis, and allows mass data filing. System software and hardware are discussed, and data display and analysis are described.<>
{"title":"Development of TSC measurement and data analysis system","authors":"T. Okamoto, N. Hozumi, J. Tanaka","doi":"10.1109/ICSD.1989.69199","DOIUrl":"https://doi.org/10.1109/ICSD.1989.69199","url":null,"abstract":"A computerized TSC (thermally stimulated current) measurement and data analysis system is described. The computer not only eliminates the X-Y recorder, but also allows data averaging, data storage, comparison with other data, and data processing for a variety of purposes. Computerization makes the data as reproducible as possible, speeds up data processing, provides accurate analysis, and allows mass data filing. System software and hardware are discussed, and data display and analysis are described.<<ETX>>","PeriodicalId":184126,"journal":{"name":"Proceedings of the 3rd International Conference on Conduction and Breakdown in Solid Dielectrics","volume":"113 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129405428","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}
A study of partial discharges (PDs) in gaseous cavities subjected to an AC voltage between dielectric surfaces, or between a metal and a dielectric, is presented. The authors present and analyze the characteristic features of discharges under AC and compare them to those obtained by J.C. Devins (1984). The present study was undertaken with a view to obtaining a better understanding of the fundamental mechanisms involved in the gassing of liquids (i.e. their ability to generate or to absorb gases under the effect of PDs). From transient current measurements and light pattern recordings, different discharge types have been analyzed. Two of the types are shown to reflect very fast and localized events, comparable to the streamer discharge regime. A third type reflects a process uniformly distributed in the cavity, attributed to the Townsend avalanche mechanism.<>
{"title":"On the mechanism of partial discharges in gaseous cavities in contact with solid or liquid insulators","authors":"P. Bezborodko, O. Lesaint, R. Tobazéon","doi":"10.1109/ICSD.1989.69227","DOIUrl":"https://doi.org/10.1109/ICSD.1989.69227","url":null,"abstract":"A study of partial discharges (PDs) in gaseous cavities subjected to an AC voltage between dielectric surfaces, or between a metal and a dielectric, is presented. The authors present and analyze the characteristic features of discharges under AC and compare them to those obtained by J.C. Devins (1984). The present study was undertaken with a view to obtaining a better understanding of the fundamental mechanisms involved in the gassing of liquids (i.e. their ability to generate or to absorb gases under the effect of PDs). From transient current measurements and light pattern recordings, different discharge types have been analyzed. Two of the types are shown to reflect very fast and localized events, comparable to the streamer discharge regime. A third type reflects a process uniformly distributed in the cavity, attributed to the Townsend avalanche mechanism.<<ETX>>","PeriodicalId":184126,"journal":{"name":"Proceedings of the 3rd International Conference on Conduction and Breakdown in Solid Dielectrics","volume":"51 7-8","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114046152","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}
After breakdown testing of a cable it is difficult to identify the cause of the breakdown, because the insulation in the region of breakdown is usually heavily damaged. The authors describe an approach in which the insulation from cables extruded under normal conditions is peeled to form continuous lengths of thin tape. Results from AC breakdown tests of these tapes and microscopic and elemental analysis of detected weak sites are presented. The density, size, and radial position of the sites were measured. The results indicate that this technique can be used to find explanations of the lower breakdown stress of cable insulation compared to the strength of insulating material measured under laboratory conditions. The number of weak insulation sites in 12-kV XLPE (cross-linked polyethylene) cables was found to vary across the insulation wall, with the highest density in a region close to the conductor screen.<>
{"title":"Location and examination of defects in XLPE cable insulation","authors":"S. T. Hagen, E. Ildstad, J. Sletbak, H. Faremo","doi":"10.1109/ICSD.1989.69261","DOIUrl":"https://doi.org/10.1109/ICSD.1989.69261","url":null,"abstract":"After breakdown testing of a cable it is difficult to identify the cause of the breakdown, because the insulation in the region of breakdown is usually heavily damaged. The authors describe an approach in which the insulation from cables extruded under normal conditions is peeled to form continuous lengths of thin tape. Results from AC breakdown tests of these tapes and microscopic and elemental analysis of detected weak sites are presented. The density, size, and radial position of the sites were measured. The results indicate that this technique can be used to find explanations of the lower breakdown stress of cable insulation compared to the strength of insulating material measured under laboratory conditions. The number of weak insulation sites in 12-kV XLPE (cross-linked polyethylene) cables was found to vary across the insulation wall, with the highest density in a region close to the conductor screen.<<ETX>>","PeriodicalId":184126,"journal":{"name":"Proceedings of the 3rd International Conference on Conduction and Breakdown in Solid Dielectrics","volume":"132 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122191831","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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