The author investigated features of the initiation of a discharge in a gaseous void of small volume, and the influence of a dielectric covering one of the surfaces enclosing a gaseous void on this phenomena. The solid dielectric specimens used were made of: (1) synthetic foil (polyethyleneterephtalate) with a thickness of 20 mu m and surface resistivity rho =10/sup 12/ Omega ; (2) transformer paper with a thickness of 100 mu m and rho =10/sup 10/ Omega ; and (3) transformer-oil-impregnated paper with a thickness of 100 mu m and rho =10/sup 8/ Omega . The use of the dielectric with the higher surface resistivity resulted in an increase of the time lag. A positive-polarity charge on the dielectric surfaces was found to considerably reduce the discharge time lag. The results show that the mechanism of discharge inception in small gas cavities is still not clear. The test results support the hypothesis that in this case the effect of a dielectric electrode coating on the discharge-inception mechanism is decisive. It is further evident that the void-enclosing surface is responsible for the emission intensity of the electrons in the rest time range from 1 to 100 s.<>
{"title":"The effect of a dielectric electrode coating on discharge inception in a gaseous void of small volume","authors":"S. Domaradzka","doi":"10.1109/ICSD.1989.69229","DOIUrl":"https://doi.org/10.1109/ICSD.1989.69229","url":null,"abstract":"The author investigated features of the initiation of a discharge in a gaseous void of small volume, and the influence of a dielectric covering one of the surfaces enclosing a gaseous void on this phenomena. The solid dielectric specimens used were made of: (1) synthetic foil (polyethyleneterephtalate) with a thickness of 20 mu m and surface resistivity rho =10/sup 12/ Omega ; (2) transformer paper with a thickness of 100 mu m and rho =10/sup 10/ Omega ; and (3) transformer-oil-impregnated paper with a thickness of 100 mu m and rho =10/sup 8/ Omega . The use of the dielectric with the higher surface resistivity resulted in an increase of the time lag. A positive-polarity charge on the dielectric surfaces was found to considerably reduce the discharge time lag. The results show that the mechanism of discharge inception in small gas cavities is still not clear. The test results support the hypothesis that in this case the effect of a dielectric electrode coating on the discharge-inception mechanism is decisive. It is further evident that the void-enclosing surface is responsible for the emission intensity of the electrons in the rest time range from 1 to 100 s.<<ETX>>","PeriodicalId":184126,"journal":{"name":"Proceedings of the 3rd International Conference on Conduction and Breakdown in Solid Dielectrics","volume":"15 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":"116715955","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. Belhadfa, A. Houdayer, P. Hinrichsen, G. Kajrys, J. Crine, R. Gilbert
The authors present laboratory results obtained with plaques of cable-grade XLPE (cross-linked polyethylene) pressed on plaques made of commercial shield compound. The samples were kept at various temperatures in air and in water for several weeks. The local impurity contents were measured at various distances from the shield-insulation interface by micro-PIXE (proton induced X-ray emission). The correlation between the impurity kinetics thus measured and impurities detected in water trees grown in XLPE cables is discussed. In addition to the elemental analysis, ionic content measurements were also performed on resins, and the ions detected correspond to the major elemental contaminants. Although it is not yet clear whether impurities affect tree growth, the fact that water and electrical trees are heavily contaminated suggests the possible influence of contamination. The nature of the most mobile impurities is also the same as those of the major contaminants in trees. The inorganic ions also correspond to these elements, which adds further evidence for their possibly detrimental role in XLPE cable aging.<>
{"title":"Migration of impurities from cable shields and tree initiation in XLPE","authors":"A. Belhadfa, A. Houdayer, P. Hinrichsen, G. Kajrys, J. Crine, R. Gilbert","doi":"10.1109/ICSD.1989.69234","DOIUrl":"https://doi.org/10.1109/ICSD.1989.69234","url":null,"abstract":"The authors present laboratory results obtained with plaques of cable-grade XLPE (cross-linked polyethylene) pressed on plaques made of commercial shield compound. The samples were kept at various temperatures in air and in water for several weeks. The local impurity contents were measured at various distances from the shield-insulation interface by micro-PIXE (proton induced X-ray emission). The correlation between the impurity kinetics thus measured and impurities detected in water trees grown in XLPE cables is discussed. In addition to the elemental analysis, ionic content measurements were also performed on resins, and the ions detected correspond to the major elemental contaminants. Although it is not yet clear whether impurities affect tree growth, the fact that water and electrical trees are heavily contaminated suggests the possible influence of contamination. The nature of the most mobile impurities is also the same as those of the major contaminants in trees. The inorganic ions also correspond to these elements, which adds further evidence for their possibly detrimental role in XLPE cable aging.<<ETX>>","PeriodicalId":184126,"journal":{"name":"Proceedings of the 3rd International Conference on Conduction and Breakdown in Solid Dielectrics","volume":"50 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":"125487934","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 interactions of streamers with polyethylene (PE), polypropylene (PP), and polyethylene terephthalate (PET) films were studied experimentally. Streamers impinging on polymers subjected to corona discharges were found to add localized disruptive effects to the dispersed chemical effects produced by the corona-activated gas. The time elapsing before disruption of a polymer film has been used to analyze the phenomenon as function of the foil thickness and the discharge current. It is shown that there are at least two different possible mechanisms of disruption, ion sputtering which has been observed on PE films, and another mechanism, observed on PP and PET films, which produces blistering effects like tears.<>
{"title":"Drilling effects of corona streamers on insulating films","authors":"L. Zibin, M. Goldman, A. Goldman, J. Gatellet","doi":"10.1109/ICSD.1989.69173","DOIUrl":"https://doi.org/10.1109/ICSD.1989.69173","url":null,"abstract":"The interactions of streamers with polyethylene (PE), polypropylene (PP), and polyethylene terephthalate (PET) films were studied experimentally. Streamers impinging on polymers subjected to corona discharges were found to add localized disruptive effects to the dispersed chemical effects produced by the corona-activated gas. The time elapsing before disruption of a polymer film has been used to analyze the phenomenon as function of the foil thickness and the discharge current. It is shown that there are at least two different possible mechanisms of disruption, ion sputtering which has been observed on PE films, and another mechanism, observed on PP and PET films, which produces blistering effects like tears.<<ETX>>","PeriodicalId":184126,"journal":{"name":"Proceedings of the 3rd International Conference on Conduction and Breakdown in Solid Dielectrics","volume":"109 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":"124066184","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 macrodefects and conduction in BN and AlN ceramics was investigated using optical and electron microscopy and X-ray analysis. Ceramic-sintering-assisted additives in the form of new impurity phases are found to exist at the aggregate interfaces only as crystalline and amorphous inclusions. Expressions that qualitatively describe the measurement results on boron nitride of different structures in the temperature range from 300 to 1800 K are obtained.<>
利用光学和电子显微镜以及 X 射线分析研究了 BN 和 AlN 陶瓷中的宏观缺陷与传导之间的关系。研究发现，陶瓷烧结辅助添加剂以新杂质相的形式存在于集合界面上，仅作为结晶和无定形夹杂物存在。在 300 至 1800 K 的温度范围内，获得了定性描述不同结构氮化硼测量结果的表达式。
{"title":"Connection of aluminum and boron nitride ceramic building with conduction","authors":"V. V. Lopatin, A. Kabyshev","doi":"10.1109/ICSD.1989.69177","DOIUrl":"https://doi.org/10.1109/ICSD.1989.69177","url":null,"abstract":"The relationship between macrodefects and conduction in BN and AlN ceramics was investigated using optical and electron microscopy and X-ray analysis. Ceramic-sintering-assisted additives in the form of new impurity phases are found to exist at the aggregate interfaces only as crystalline and amorphous inclusions. Expressions that qualitatively describe the measurement results on boron nitride of different structures in the temperature range from 300 to 1800 K are obtained.<<ETX>>","PeriodicalId":184126,"journal":{"name":"Proceedings of the 3rd International Conference on Conduction and Breakdown in Solid Dielectrics","volume":"2 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":"129888344","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 carrier mobility was determined for plain and doped low-density polyethylene (LDPE) using DC transient currents. Barium titanate was used as a strongly polar dopant and titanium dioxide as a semiconductor dopant. The values of the mobility obtained were on the order of 10/sup -10/ cm/sup 2/ v/sup -1/ s/sup -1/. Results indicate that the inclusion of 1% by weight of BaTiO/sub 3/ and TiO/sub 2/ has a considerable effect on the conduction properties of the polymer. BaTiO/sub 3/ increased the charge carrier mobility by a factor of three and also increased the conductivity of the polymer. TiO/sub 2/ increased the charge carrier mobility by a factor of five. Charge trapping and space charge formation were modified by the introduction of titanium dioxide.<>
{"title":"Determination of charge carrier mobility in doped low density polyethylene using DC transients","authors":"M. Khalil, P. Henk, M. Henriksen","doi":"10.1109/ICSD.1989.69187","DOIUrl":"https://doi.org/10.1109/ICSD.1989.69187","url":null,"abstract":"Charge carrier mobility was determined for plain and doped low-density polyethylene (LDPE) using DC transient currents. Barium titanate was used as a strongly polar dopant and titanium dioxide as a semiconductor dopant. The values of the mobility obtained were on the order of 10/sup -10/ cm/sup 2/ v/sup -1/ s/sup -1/. Results indicate that the inclusion of 1% by weight of BaTiO/sub 3/ and TiO/sub 2/ has a considerable effect on the conduction properties of the polymer. BaTiO/sub 3/ increased the charge carrier mobility by a factor of three and also increased the conductivity of the polymer. TiO/sub 2/ increased the charge carrier mobility by a factor of five. Charge trapping and space charge formation were modified by the introduction of titanium dioxide.<<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":"130190795","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}
Results of numerical computations show that a growth model based on the water treeing model concept of dielectrophoresis leads to the size distributions of water trees found in high-voltage cables removed from service. After some time a peaked distribution of water tree sizes occurs, whereby the shift of the maximum in time decreases with increasing length of the water trees. The model predicts in increase of the growth rate with increasing water concentration in the trees. The influence of the characteristic parameters of the defect that initiated the water tree diminishes with increasing length of the water tree.<>
{"title":"Water trees-growth rate and model concept","authors":"R. Patsch","doi":"10.1109/ICSD.1989.69247","DOIUrl":"https://doi.org/10.1109/ICSD.1989.69247","url":null,"abstract":"Results of numerical computations show that a growth model based on the water treeing model concept of dielectrophoresis leads to the size distributions of water trees found in high-voltage cables removed from service. After some time a peaked distribution of water tree sizes occurs, whereby the shift of the maximum in time decreases with increasing length of the water trees. The model predicts in increase of the growth rate with increasing water concentration in the trees. The influence of the characteristic parameters of the defect that initiated the water tree diminishes with increasing length of the water tree.<<ETX>>","PeriodicalId":184126,"journal":{"name":"Proceedings of the 3rd International Conference on Conduction and Breakdown in Solid Dielectrics","volume":"5 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":"124872228","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. Albini, G. Degli Esposti, F. Guastavino, D. Tommasini
The influence of additives and impurities on conduction and polarization mechanisms in thin films of polypropylene was investigated. It was assumed that the charging current is made up of three components: a polarization component produced by dipole orientation, a conduction current, and a fast transient. The cause of each component was identified by means of a special nonlinear iterative algorithm based on the least-squares method. The results of this investigation show an influence of the additive content and of the temperature on the charging current that can be ascribed to the bulk composition of the materials. It is noted that it is very important to fit the experimental data in order to obtain the correct values of the steady-state conduction currents, which are more significant than the currents obtained at a fixed time.<>
{"title":"Charging phenomena in polypropylene films","authors":"A. Albini, G. Degli Esposti, F. Guastavino, D. Tommasini","doi":"10.1109/ICSD.1989.69178","DOIUrl":"https://doi.org/10.1109/ICSD.1989.69178","url":null,"abstract":"The influence of additives and impurities on conduction and polarization mechanisms in thin films of polypropylene was investigated. It was assumed that the charging current is made up of three components: a polarization component produced by dipole orientation, a conduction current, and a fast transient. The cause of each component was identified by means of a special nonlinear iterative algorithm based on the least-squares method. The results of this investigation show an influence of the additive content and of the temperature on the charging current that can be ascribed to the bulk composition of the materials. It is noted that it is very important to fit the experimental data in order to obtain the correct values of the steady-state conduction currents, which are more significant than the currents obtained at a fixed time.<<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":"117086502","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 investigated the ageing of polyethylene under inhomogeneous electric fields well below the intrinsic breakdown field strength (>570 kV/mm RMS) but above a local critical field strength at which charge injection takes place. They observed partial discharge and the treeing behavior under different conditions of AC and DC stressing. Additional experiments with samples impregnated with an electronegative gas (SF/sub 6/) yielded further information on the process of polymer degradation. The results show that there is no deterioration during DC ageing; the polarity reversal that occurs under AC stressing is necessary for the ageing process. The observation of brittle walls of the tree structure indicates that the rate of impingement of hot electrons on the polymer is relatively low. Therefore the heat produced may be easily dissipated without appreciable rise of the temperature within the treed region. The experiments with the impregnated samples are in agreement with the assumption of a hot electron process. The SF/sub 6/ captures hot electrons and therefore reduces the probability of damage; in the present case no deterioration is observable up to 600 h.<>
{"title":"Electrical ageing of polyethylene during constant AC stress","authors":"P. Rohl, K. Nissen, W. Rose","doi":"10.1109/ICSD.1989.69160","DOIUrl":"https://doi.org/10.1109/ICSD.1989.69160","url":null,"abstract":"The authors investigated the ageing of polyethylene under inhomogeneous electric fields well below the intrinsic breakdown field strength (>570 kV/mm RMS) but above a local critical field strength at which charge injection takes place. They observed partial discharge and the treeing behavior under different conditions of AC and DC stressing. Additional experiments with samples impregnated with an electronegative gas (SF/sub 6/) yielded further information on the process of polymer degradation. The results show that there is no deterioration during DC ageing; the polarity reversal that occurs under AC stressing is necessary for the ageing process. The observation of brittle walls of the tree structure indicates that the rate of impingement of hot electrons on the polymer is relatively low. Therefore the heat produced may be easily dissipated without appreciable rise of the temperature within the treed region. The experiments with the impregnated samples are in agreement with the assumption of a hot electron process. The SF/sub 6/ captures hot electrons and therefore reduces the probability of damage; in the present case no deterioration is observable up to 600 h.<<ETX>>","PeriodicalId":184126,"journal":{"name":"Proceedings of the 3rd International Conference on Conduction and Breakdown in Solid Dielectrics","volume":"82 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":"123064735","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}
Results of DC electrical conductivity measurements performed at different aging times on cross-linked polyethylene (XLPE) cable models subjected to thermal and combined thermal-electrical stresses are discussed. It is shown that the variations of electrical conductivity with aging time are related to those of other properties (density, crystallinity, electric strength, and microstructure) and hence to the aging processes. Electrical conductivity is shown to be a bulk property well able to indicate the degradation of an insulating material due to electrical and thermal stresses, even if the failure due to electrical stress is primarily a localized phenomenon.<>
{"title":"Degradation and electrical behavior of aged XLPE cable models","authors":"A. Motori, F. Sandrolini, G. Montanari","doi":"10.1109/ICSD.1989.69219","DOIUrl":"https://doi.org/10.1109/ICSD.1989.69219","url":null,"abstract":"Results of DC electrical conductivity measurements performed at different aging times on cross-linked polyethylene (XLPE) cable models subjected to thermal and combined thermal-electrical stresses are discussed. It is shown that the variations of electrical conductivity with aging time are related to those of other properties (density, crystallinity, electric strength, and microstructure) and hence to the aging processes. Electrical conductivity is shown to be a bulk property well able to indicate the degradation of an insulating material due to electrical and thermal stresses, even if the failure due to electrical stress is primarily a localized phenomenon.<<ETX>>","PeriodicalId":184126,"journal":{"name":"Proceedings of the 3rd International Conference on Conduction and Breakdown in Solid Dielectrics","volume":"49 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":"129498855","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 TSDC (thermally stimulated depolarization current) method was used to study the effect of polymer structure on electrical properties for poly(phenylquinooxaline). Seven relaxation regions were distinguished in the TSDC spectrum. The probability of observing the regions depends strongly on the degree of annealing of the samples. The TSDC in PETP is also found to be influenced by the physical structure. The TSDC spectrum of pure and saponificated poly(methylmethacrylate) was investigated. Three relaxation regions were observed: the beta - and alpha -relaxation and a space charge relaxation.<>
{"title":"The influence of the polymer structure on the electrical properties","authors":"H. Hansel","doi":"10.1109/ICSD.1989.69192","DOIUrl":"https://doi.org/10.1109/ICSD.1989.69192","url":null,"abstract":"The TSDC (thermally stimulated depolarization current) method was used to study the effect of polymer structure on electrical properties for poly(phenylquinooxaline). Seven relaxation regions were distinguished in the TSDC spectrum. The probability of observing the regions depends strongly on the degree of annealing of the samples. The TSDC in PETP is also found to be influenced by the physical structure. The TSDC spectrum of pure and saponificated poly(methylmethacrylate) was investigated. Three relaxation regions were observed: the beta - and alpha -relaxation and a space charge relaxation.<<ETX>>","PeriodicalId":184126,"journal":{"name":"Proceedings of the 3rd International Conference on Conduction and Breakdown in Solid Dielectrics","volume":"7 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":"127884419","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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