The early phases of the internal and external spacer surface degradation process were characterized using electrical and chemical techniques in order to develop a better understanding of the long-term aging mechanisms. Reaction of nitrogen gas in a discharge cavity with the epoxy void wall was readily detected by ESCA (electron spectroscopy for chemical analysis), and the technique could find application in determining the void size below which no damage occurs. A similarly substantial modification of spacer surface properties could be brought about by exposure to localized corona discharges, associated with material transfer from the electrode and leading ultimately to the formation of tracklike paths on the epoxy surface. The results are of interest in connection with the electrical treeing of GIS (gas-insulated switchgear) spacers.<>
{"title":"Studies of epoxy spacers subjected to internal and external partial discharge and SF/sub 6/ byproducts","authors":"J. Braun, F. Chu, A. Tymań","doi":"10.1109/ICSD.1989.69217","DOIUrl":"https://doi.org/10.1109/ICSD.1989.69217","url":null,"abstract":"The early phases of the internal and external spacer surface degradation process were characterized using electrical and chemical techniques in order to develop a better understanding of the long-term aging mechanisms. Reaction of nitrogen gas in a discharge cavity with the epoxy void wall was readily detected by ESCA (electron spectroscopy for chemical analysis), and the technique could find application in determining the void size below which no damage occurs. A similarly substantial modification of spacer surface properties could be brought about by exposure to localized corona discharges, associated with material transfer from the electrode and leading ultimately to the formation of tracklike paths on the epoxy surface. The results are of interest in connection with the electrical treeing of GIS (gas-insulated switchgear) spacers.<<ETX>>","PeriodicalId":184126,"journal":{"name":"Proceedings of the 3rd International Conference on Conduction and Breakdown in Solid Dielectrics","volume":"14 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":"123622119","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}
To study the relationship between the composition of the dielectric surface and the potential barrier, photocurrent spectra were measured for cleared mica (muscovite) which could be expected theoretically not to have any free chemical bonds at its surface. Barrier heights and densities of surface states were examined for specimens whose surfaces were irradiated by a neutral Ar beam to remove contamination and adsorbed gas or to modify their composition. It was found that the barrier height of a mica-metal contact was not altered by a short period of irradiation with the Ar beam or by exposure to the air after irradiation. A long period of irradiation (40 min) resulted in damage to the mica surface, and the density of surface states increased up to about 3 times (1.2*10/sup 14/ states cm/sup -2/ eV/sup -1/) that of the untreated specimen. It was found by ESCA (electron spectroscopy for chemical analysis) that potassium and sodium atoms were sputtered by the long period of irradiation, causing imperfections or disordering in the surface structure of the mica. The surface states created by the irradiation are believed to be dependent on the free bonds that formed as a result of the above imperfections.<>
{"title":"Potential barrier of mica-metal contact","authors":"T. Sakakibara, N. Aeba, M. Endo","doi":"10.1109/ICSD.1989.69156","DOIUrl":"https://doi.org/10.1109/ICSD.1989.69156","url":null,"abstract":"To study the relationship between the composition of the dielectric surface and the potential barrier, photocurrent spectra were measured for cleared mica (muscovite) which could be expected theoretically not to have any free chemical bonds at its surface. Barrier heights and densities of surface states were examined for specimens whose surfaces were irradiated by a neutral Ar beam to remove contamination and adsorbed gas or to modify their composition. It was found that the barrier height of a mica-metal contact was not altered by a short period of irradiation with the Ar beam or by exposure to the air after irradiation. A long period of irradiation (40 min) resulted in damage to the mica surface, and the density of surface states increased up to about 3 times (1.2*10/sup 14/ states cm/sup -2/ eV/sup -1/) that of the untreated specimen. It was found by ESCA (electron spectroscopy for chemical analysis) that potassium and sodium atoms were sputtered by the long period of irradiation, causing imperfections or disordering in the surface structure of the mica. The surface states created by the irradiation are believed to be dependent on the free bonds that formed as a result of the above imperfections.<<ETX>>","PeriodicalId":184126,"journal":{"name":"Proceedings of the 3rd International Conference on Conduction and Breakdown in Solid Dielectrics","volume":"46 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":"124180290","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}
J. Suñé, I. Placencia, E. Farrés, N. Barniol, X. Aymerich
It is shown that the experimental breakdown distributions for thin SiO/sub 2/ films can be explained by assuming that the breakdown is closely related to the degradation of its structure. The model, relating the degradation to the generation of neutron trapping sites, is compatible with the use of extreme-value distributions, and it also provides a simple physical interpretation of the parameters involved. The fact that the local breakdown area has been found to be always of the same order of magnitude provides further support for the proposed model. The failure distributions obtained under constant-current and constant-voltage stresses is compared with the widely used Weibull distribution. Results of Monte Carlo simulations of the breakdown statistics are reported.<>
{"title":"On the breakdown statistics of thin SiO/sub 2/ films","authors":"J. Suñé, I. Placencia, E. Farrés, N. Barniol, X. Aymerich","doi":"10.1109/ICSD.1989.69221","DOIUrl":"https://doi.org/10.1109/ICSD.1989.69221","url":null,"abstract":"It is shown that the experimental breakdown distributions for thin SiO/sub 2/ films can be explained by assuming that the breakdown is closely related to the degradation of its structure. The model, relating the degradation to the generation of neutron trapping sites, is compatible with the use of extreme-value distributions, and it also provides a simple physical interpretation of the parameters involved. The fact that the local breakdown area has been found to be always of the same order of magnitude provides further support for the proposed model. The failure distributions obtained under constant-current and constant-voltage stresses is compared with the widely used Weibull distribution. Results of Monte Carlo simulations of the breakdown statistics are reported.<<ETX>>","PeriodicalId":184126,"journal":{"name":"Proceedings of the 3rd International Conference on Conduction and Breakdown in Solid Dielectrics","volume":"3 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":"128063536","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.G. Sumangala, P. Poovamma, K. Dwarakanath, K.S. Arunachala Sastry, M. Ratra
The influence on certain important electrical properties such as insulation resistance, breakdown voltage, comparative tracking index (CTI), and arc resistance in industrial organic laminates is discussed. Four different types of laminates-paper phenolic, glass-epoxy, glass-melanine, and sheet molding compounds-were selected for the investigation. The influence of araldite coating on the sides of the specimens was also investigated for some of the properties mentioned above. It is shown that glass-epoxy laminates and paper phenolic laminates exhibit very good and very poor performance, respectively. The behavior of CTI and the arc resistance of the laminates with respect to electrode material suggest that the physical processes responsible for the degradation of the material are entirely different than for the other properties. The araldite coating did not improve the properties. Instead it had an adverse effect on most of the characteristics.<>
{"title":"Degradation of electrical properties of organic industrial laminates due to moisture absorption","authors":"M.G. Sumangala, P. Poovamma, K. Dwarakanath, K.S. Arunachala Sastry, M. Ratra","doi":"10.1109/ICSD.1989.69246","DOIUrl":"https://doi.org/10.1109/ICSD.1989.69246","url":null,"abstract":"The influence on certain important electrical properties such as insulation resistance, breakdown voltage, comparative tracking index (CTI), and arc resistance in industrial organic laminates is discussed. Four different types of laminates-paper phenolic, glass-epoxy, glass-melanine, and sheet molding compounds-were selected for the investigation. The influence of araldite coating on the sides of the specimens was also investigated for some of the properties mentioned above. It is shown that glass-epoxy laminates and paper phenolic laminates exhibit very good and very poor performance, respectively. The behavior of CTI and the arc resistance of the laminates with respect to electrode material suggest that the physical processes responsible for the degradation of the material are entirely different than for the other properties. The araldite coating did not improve the properties. Instead it had an adverse effect on most of the characteristics.<<ETX>>","PeriodicalId":184126,"journal":{"name":"Proceedings of the 3rd International Conference on Conduction and Breakdown in Solid Dielectrics","volume":"18 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":"126840459","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}
It has been suggested that polymer laminates in which a charge has accumulated at the interface of two polymers will exhibit piezoelectric properties. It has also been suggested that a composite which consists of a polymer matrix and dispersed inorganic ferroelectric particles exhibits piezoelectricity after poling. The author proposed a technique of multielement electret preparation that is based on these two concepts. A partially oriented polyethylene terephthalate (PET) film and a composite of polymethyl methacrylate (PMMA) and powdered BaTiO/sub 3/ ceramics are used. The technique does not require conventional poling by an external electric field procedure. It is shown that the best polarization effects can be obtained in the uncharged PET-PMMA/BaTiO/sub 3/-PET laminate and its separated films. This laminate can have interesting piezoelectric properties due to its heterogeneity and the charges embedded at the interface between the PET and PMMA/BaTiO/sub 3/ films.<>
{"title":"Polarization effects in uncharged laminates","authors":"K. Mazur","doi":"10.1109/ICSD.1989.69236","DOIUrl":"https://doi.org/10.1109/ICSD.1989.69236","url":null,"abstract":"It has been suggested that polymer laminates in which a charge has accumulated at the interface of two polymers will exhibit piezoelectric properties. It has also been suggested that a composite which consists of a polymer matrix and dispersed inorganic ferroelectric particles exhibits piezoelectricity after poling. The author proposed a technique of multielement electret preparation that is based on these two concepts. A partially oriented polyethylene terephthalate (PET) film and a composite of polymethyl methacrylate (PMMA) and powdered BaTiO/sub 3/ ceramics are used. The technique does not require conventional poling by an external electric field procedure. It is shown that the best polarization effects can be obtained in the uncharged PET-PMMA/BaTiO/sub 3/-PET laminate and its separated films. This laminate can have interesting piezoelectric properties due to its heterogeneity and the charges embedded at the interface between the PET and PMMA/BaTiO/sub 3/ films.<<ETX>>","PeriodicalId":184126,"journal":{"name":"Proceedings of the 3rd International Conference on Conduction and Breakdown in Solid Dielectrics","volume":"41 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":"129390678","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}
Two models, a modified Sterne-Weaver model and the hopping model, have been developed to study the dielectric response of materials containing mobile charge. The first model is the same as the basic Sterne-Weaver model except that both species of charge carrier are free to move. It is shown that by regarding the movement of the charge carrier as a hopping process across a potential barrier of specified height and width, the effects of the applied electric field on the movement of the carriers can be calculated by considering the modifications it causes to the successful-jump probability. The two models behave in a similar fashion under steady-state conditions. This contrasts with the behavior described previously, when lower values of activation energy (higher mobilities) were used. Under those conditions an order of magnitude change was observed in the polarization response of the two models coupled with a considerable difference in the phase relationship of the polarization to the applied field. In addition, a transient component of polarization is observed in the present study that was not observed previously.<>
{"title":"Further results from the modeling of the dielectric response of materials containing mobile charge","authors":"M. Given, R. Fouracre","doi":"10.1109/ICSD.1989.69186","DOIUrl":"https://doi.org/10.1109/ICSD.1989.69186","url":null,"abstract":"Two models, a modified Sterne-Weaver model and the hopping model, have been developed to study the dielectric response of materials containing mobile charge. The first model is the same as the basic Sterne-Weaver model except that both species of charge carrier are free to move. It is shown that by regarding the movement of the charge carrier as a hopping process across a potential barrier of specified height and width, the effects of the applied electric field on the movement of the carriers can be calculated by considering the modifications it causes to the successful-jump probability. The two models behave in a similar fashion under steady-state conditions. This contrasts with the behavior described previously, when lower values of activation energy (higher mobilities) were used. Under those conditions an order of magnitude change was observed in the polarization response of the two models coupled with a considerable difference in the phase relationship of the polarization to the applied field. In addition, a transient component of polarization is observed in the present study that was not observed previously.<<ETX>>","PeriodicalId":184126,"journal":{"name":"Proceedings of the 3rd International Conference on Conduction and Breakdown in Solid Dielectrics","volume":"30 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":"133047728","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}
Different statistical methods used for the determination of the insulation characteristics of solid insulating materials are reviewed. Experimental results reported in the literature indicate that the breakdown probability of the test voltages is a function of the test method, of their parameters, and of the nature of the breakdown probability function. The application of statistical methods to establish the insulation strength and lifetime is described. Techniques for determining withstand voltages of electrical insulation and for determining the low probability of breakdown of solid insulation from critical flashover data are discussed. The application of the Weibull distribution for the description of breakdown data is examined. It is noted that great care must be used in interpreting statistical test results, due to the flexibility of low-breakdown-probability test methods. Example test results are presented for three groups of epoxy specimens.<>
{"title":"Review of statistical testing of solid insulating materials","authors":"M. Morcos, S.E. Cherukupalli","doi":"10.1109/ICSD.1989.69262","DOIUrl":"https://doi.org/10.1109/ICSD.1989.69262","url":null,"abstract":"Different statistical methods used for the determination of the insulation characteristics of solid insulating materials are reviewed. Experimental results reported in the literature indicate that the breakdown probability of the test voltages is a function of the test method, of their parameters, and of the nature of the breakdown probability function. The application of statistical methods to establish the insulation strength and lifetime is described. Techniques for determining withstand voltages of electrical insulation and for determining the low probability of breakdown of solid insulation from critical flashover data are discussed. The application of the Weibull distribution for the description of breakdown data is examined. It is noted that great care must be used in interpreting statistical test results, due to the flexibility of low-breakdown-probability test methods. Example test results are presented for three groups of epoxy specimens.<<ETX>>","PeriodicalId":184126,"journal":{"name":"Proceedings of the 3rd International Conference on Conduction and Breakdown in Solid Dielectrics","volume":"75 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":"129699455","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}
Specific groups in water trees have been characterized by Fourier transform infrared (FTIR) microspectrometry. The stability of these groups with respect to several solvents was studied, and the luminescence of water trees was compared with their methylene blue image. The water tree samples were taken from four cables aged in the laboratory or in service. They were luminescent, although in one case very weakly, and the luminescent areas corresponding closely to the stained regions. Water trees are polar regions in polyethene, as evidenced by an immersion and evacuation experiment. The chemical components of water trees show some variety. The groups resulting from immersion could not be washed out by selected solvents. An interaction between some of these groups and the solvents could, however, be established by FTIR microspectrometry. In the cases investigated, the water trees seem to contain carboxylate groups attached to the polyethene. If so, this might be the result of an oxidation process of which carboxylate is the main product rather than ketones or aldehydes.<>
{"title":"Watertrees in polyethene studied by luminescence and FTIR microspectrometry","authors":"R. Ross, W. Geurts, J. Smit, J. Maas, E. Lutz","doi":"10.1109/ICSD.1989.69251","DOIUrl":"https://doi.org/10.1109/ICSD.1989.69251","url":null,"abstract":"Specific groups in water trees have been characterized by Fourier transform infrared (FTIR) microspectrometry. The stability of these groups with respect to several solvents was studied, and the luminescence of water trees was compared with their methylene blue image. The water tree samples were taken from four cables aged in the laboratory or in service. They were luminescent, although in one case very weakly, and the luminescent areas corresponding closely to the stained regions. Water trees are polar regions in polyethene, as evidenced by an immersion and evacuation experiment. The chemical components of water trees show some variety. The groups resulting from immersion could not be washed out by selected solvents. An interaction between some of these groups and the solvents could, however, be established by FTIR microspectrometry. In the cases investigated, the water trees seem to contain carboxylate groups attached to the polyethene. If so, this might be the result of an oxidation process of which carboxylate is the main product rather than ketones or aldehydes.<<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":"130047413","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}
N. Mann, P. Vasudevan, Santosh, Sandhya., B. Bhushan, S. Mathur, J. Chauhan
The conductivity and dielectric properties of monomeric and polymeric cobalt phthalocyanine (CoPc) prepared under different conditions are discussed. All CoPc derivatives studied show very high specific conductivity as compared to microscopic-grade CoPc. The dielectric constants are frequency dependent, with the highest response occurring at the lower frequencies of the applied electric field, indicative of nomadic polarization. The dielectric constant increases strongly with temperature.<>
{"title":"Electrical properties of some cobalt phthalocyanines","authors":"N. Mann, P. Vasudevan, Santosh, Sandhya., B. Bhushan, S. Mathur, J. Chauhan","doi":"10.1109/ICSD.1989.69181","DOIUrl":"https://doi.org/10.1109/ICSD.1989.69181","url":null,"abstract":"The conductivity and dielectric properties of monomeric and polymeric cobalt phthalocyanine (CoPc) prepared under different conditions are discussed. All CoPc derivatives studied show very high specific conductivity as compared to microscopic-grade CoPc. The dielectric constants are frequency dependent, with the highest response occurring at the lower frequencies of the applied electric field, indicative of nomadic polarization. The dielectric constant increases strongly with temperature.<<ETX>>","PeriodicalId":184126,"journal":{"name":"Proceedings of the 3rd International Conference on Conduction and Breakdown in Solid Dielectrics","volume":"21 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":"131030053","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}
Studies to determine the transport mechanism of hydrogen gas in laminated dielectric materials of practical interest have been performed. Partial-discharge activity was investigated as a function of pressure reduction. The controlled variables were composition of the insulation system, ambient pressure, temperature, and molecular size of the penetrating gas. The egress times indicate that a temporary reduction in hydrogen pressure to more easily detect partial-discharge activity in a turbine generator is a feasible procedure. However, the short time lags found are in contrast to those predicted theoretically for solid slabs. They are also contrary to experience with homogeneous epoxy resins. Therefore it is probable that the predominant gas transport mechanism is effusion, due to minute cracks in the insulation, rather than molecular diffusion.<>
{"title":"Partial discharge behaviour in laminated structures: effect of gaseous diffusion and penetration (turbine generators)","authors":"H. Sedding, J. Braun","doi":"10.1109/ICSD.1989.69174","DOIUrl":"https://doi.org/10.1109/ICSD.1989.69174","url":null,"abstract":"Studies to determine the transport mechanism of hydrogen gas in laminated dielectric materials of practical interest have been performed. Partial-discharge activity was investigated as a function of pressure reduction. The controlled variables were composition of the insulation system, ambient pressure, temperature, and molecular size of the penetrating gas. The egress times indicate that a temporary reduction in hydrogen pressure to more easily detect partial-discharge activity in a turbine generator is a feasible procedure. However, the short time lags found are in contrast to those predicted theoretically for solid slabs. They are also contrary to experience with homogeneous epoxy resins. Therefore it is probable that the predominant gas transport mechanism is effusion, due to minute cracks in the insulation, rather than molecular diffusion.<<ETX>>","PeriodicalId":184126,"journal":{"name":"Proceedings of the 3rd International Conference on Conduction and Breakdown in Solid Dielectrics","volume":"75 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":"131209242","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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