Water-tree counting measurements, water and impurity content measurements, and AC breakdown tests were performed on several field-aged medium-voltage extruded cables. The results indicate that the water-tree density increases with the insulation contamination level, particularly for aluminium, sodium, and potassium contaminant. However, neither of these aging factors seems to be correlated with the residual dielectric strength, which, on the contrary, is clearly influenced by the water content. In fact, the results suggest that water is the major aging factor of XLPE (cross-linked polyethylene) cables.<>
{"title":"Effect of water on the performance of XLPE insulation","authors":"S. Pélissou","doi":"10.1109/ICSD.1989.69235","DOIUrl":"https://doi.org/10.1109/ICSD.1989.69235","url":null,"abstract":"Water-tree counting measurements, water and impurity content measurements, and AC breakdown tests were performed on several field-aged medium-voltage extruded cables. The results indicate that the water-tree density increases with the insulation contamination level, particularly for aluminium, sodium, and potassium contaminant. However, neither of these aging factors seems to be correlated with the residual dielectric strength, which, on the contrary, is clearly influenced by the water content. In fact, the results suggest that water is the major aging factor of XLPE (cross-linked polyethylene) cables.<<ETX>>","PeriodicalId":184126,"journal":{"name":"Proceedings of the 3rd International Conference on Conduction and Breakdown in Solid Dielectrics","volume":"19 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":"114376772","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 temperature gradient of crystal lattice spacings and X-ray reflection intensities has been found to change discontinuously at 150 degrees C for cellulose I (Cell I) and at 100 degrees C for cellulose II (Cell II). These breaks reflect a transition related to the onset of the backbone motion in the crystalline phase. The authors have attempted to confirm this conclusion by measuring the DC conductivity from room temperature to about 230 degrees C for Cell I and Cell II both parallel and perpendicular to the fiber direction. The conduction mechanism is discussed in relation to the absorption current of Cell I under a DC field in the temperature range from 140 degrees C to 230 degrees C, where the DC conductivity becomes relatively high. The results indicate that the increase of carrier mobility above the transition temperature of crystallites arises from the backbone motion in the disordered crystalline phase (mesophase) and that proton transfer is an elementary mechanism for both absorption and steady currents.<>
{"title":"Electrical conduction of cellulose under DC field","authors":"M. Takahashi, H. Takenaka, Y. Wada","doi":"10.1109/ICSD.1989.69185","DOIUrl":"https://doi.org/10.1109/ICSD.1989.69185","url":null,"abstract":"The temperature gradient of crystal lattice spacings and X-ray reflection intensities has been found to change discontinuously at 150 degrees C for cellulose I (Cell I) and at 100 degrees C for cellulose II (Cell II). These breaks reflect a transition related to the onset of the backbone motion in the crystalline phase. The authors have attempted to confirm this conclusion by measuring the DC conductivity from room temperature to about 230 degrees C for Cell I and Cell II both parallel and perpendicular to the fiber direction. The conduction mechanism is discussed in relation to the absorption current of Cell I under a DC field in the temperature range from 140 degrees C to 230 degrees C, where the DC conductivity becomes relatively high. The results indicate that the increase of carrier mobility above the transition temperature of crystallites arises from the backbone motion in the disordered crystalline phase (mesophase) and that proton transfer is an elementary mechanism for both absorption and steady currents.<<ETX>>","PeriodicalId":184126,"journal":{"name":"Proceedings of the 3rd International Conference on Conduction and Breakdown in Solid Dielectrics","volume":"25 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":"114547145","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}
M. Nagao, T. Kitamura, Y. Mizuno, M. Kosaki, M. Ieda
The contribution of the thermal process to DC electrical breakdown of polyethylene films at room temperature was investigated along with the character and the distribution of the weak points in the films. Local Joule heating in polyethylene film was detected before DC electrical breakdown at room temperature. When a high-temperature point appeared in a film, the conduction current increased with time. An analysis of the time variation of the conduction current and the temperature rise showed that the current flows mainly around the high-temperature point. The final breakdown occurred at the point of the highest temperature. The concurrence of the breakdown point and the Joule heating point suggests that a thermal process takes part in the DC electrical breakdown of polyethylene films at room temperature and that the weak points leading to the breakdown in the film occur where the current density is higher than the average. Local electromechanical deformation also appears to contribute to the DC electrical breakdown of polyethylene.<>
{"title":"Localized heat generation before dielectric breakdown of polyethylene films","authors":"M. Nagao, T. Kitamura, Y. Mizuno, M. Kosaki, M. Ieda","doi":"10.1109/ICSD.1989.69165","DOIUrl":"https://doi.org/10.1109/ICSD.1989.69165","url":null,"abstract":"The contribution of the thermal process to DC electrical breakdown of polyethylene films at room temperature was investigated along with the character and the distribution of the weak points in the films. Local Joule heating in polyethylene film was detected before DC electrical breakdown at room temperature. When a high-temperature point appeared in a film, the conduction current increased with time. An analysis of the time variation of the conduction current and the temperature rise showed that the current flows mainly around the high-temperature point. The final breakdown occurred at the point of the highest temperature. The concurrence of the breakdown point and the Joule heating point suggests that a thermal process takes part in the DC electrical breakdown of polyethylene films at room temperature and that the weak points leading to the breakdown in the film occur where the current density is higher than the average. Local electromechanical deformation also appears to contribute to the DC electrical breakdown of polyethylene.<<ETX>>","PeriodicalId":184126,"journal":{"name":"Proceedings of the 3rd International Conference on Conduction and Breakdown in Solid Dielectrics","volume":"95 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":"124420333","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}
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}
Dielectric spectroscopy was used to investigate conduction processes in zinc oxide varistors. Initial results on the complex dielectric permittivity with and without an applied DC bias are presented. Some novel features in the dielectric properties of ZnO varistors that deserve further study were revealed. The differences between the measured epsilon (f) of thick and thin samples are little understood at present. A possibility is that uninterrupted channels of intergranular Bi-rich phases are more likely to be present in thin samples, increasing the importance of this conduction path.<>
{"title":"Dielectric properties of zinc oxide based varistors","authors":"K. Brantervik, G. Niklasson","doi":"10.1109/ICSD.1989.69210","DOIUrl":"https://doi.org/10.1109/ICSD.1989.69210","url":null,"abstract":"Dielectric spectroscopy was used to investigate conduction processes in zinc oxide varistors. Initial results on the complex dielectric permittivity with and without an applied DC bias are presented. Some novel features in the dielectric properties of ZnO varistors that deserve further study were revealed. The differences between the measured epsilon (f) of thick and thin samples are little understood at present. A possibility is that uninterrupted channels of intergranular Bi-rich phases are more likely to be present in thin samples, increasing the importance of this conduction path.<<ETX>>","PeriodicalId":184126,"journal":{"name":"Proceedings of the 3rd International Conference on Conduction and Breakdown in Solid Dielectrics","volume":"10 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":"127565818","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}
Charge injection is known to occur in the prebreakdown stage in polymeric materials. It has recently been demonstrated that a time-resolved measurement of this charge is possible in a double-needle electrode configuration and under AC voltage using an analog experimental setup with a sensitivity of approximately=10/sup -14/ C. A critical field for charge injection has been defined in two polymeric materials (polyethylene and epoxy resin). The authors report data on the temporal evolution of the charge during AC polarization. Results show that continuous space charge injection occurs during ageing of the polymeric samples. Some of the injected carriers are permanently trapped in the dielectric.<>
{"title":"In stress space charge probing during ageing of polymeric samples","authors":"T. Lebey, C. Laurent, C. Mayoux","doi":"10.1109/ICSD.1989.69158","DOIUrl":"https://doi.org/10.1109/ICSD.1989.69158","url":null,"abstract":"Charge injection is known to occur in the prebreakdown stage in polymeric materials. It has recently been demonstrated that a time-resolved measurement of this charge is possible in a double-needle electrode configuration and under AC voltage using an analog experimental setup with a sensitivity of approximately=10/sup -14/ C. A critical field for charge injection has been defined in two polymeric materials (polyethylene and epoxy resin). The authors report data on the temporal evolution of the charge during AC polarization. Results show that continuous space charge injection occurs during ageing of the polymeric samples. Some of the injected carriers are permanently trapped in the dielectric.<<ETX>>","PeriodicalId":184126,"journal":{"name":"Proceedings of the 3rd International Conference on Conduction and Breakdown in Solid Dielectrics","volume":"248 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":"116162418","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}
The authors present results of investigations of nonequilibrium conduction and thermally stimulated luminescence (TSL) carried out on PBN (pyrolitic boron nitride) using modulated thermally activated spectroscopy (MTAS). In analyzing the results the authors used the TSL spectra and luminescence stimulated by X-ray emission. To find the position of the energetic levels of local energetic states in the bandgap, which were observed with the MTAS technique, the sign of the charge carriers causing conduction was determined. The techniques used made it possible to observe the transport characteristics and the parameters of the local levels in the heterogeneous polycrystalline materials.<>
{"title":"The effect of energetic states of BN band gap on conduction","authors":"V. V. Lopatin, Y.I. Galanov, F. Konusov","doi":"10.1109/ICSD.1989.69175","DOIUrl":"https://doi.org/10.1109/ICSD.1989.69175","url":null,"abstract":"The authors present results of investigations of nonequilibrium conduction and thermally stimulated luminescence (TSL) carried out on PBN (pyrolitic boron nitride) using modulated thermally activated spectroscopy (MTAS). In analyzing the results the authors used the TSL spectra and luminescence stimulated by X-ray emission. To find the position of the energetic levels of local energetic states in the bandgap, which were observed with the MTAS technique, the sign of the charge carriers causing conduction was determined. The techniques used made it possible to observe the transport characteristics and the parameters of the local levels in the heterogeneous polycrystalline materials.<<ETX>>","PeriodicalId":184126,"journal":{"name":"Proceedings of the 3rd International Conference on Conduction and Breakdown in Solid Dielectrics","volume":"95 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":"125561403","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}
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