Pub Date : 1991-07-08DOI: 10.1109/ICPADM.1991.172304
G. Liang-yu, Liu Yaonan, Xi Baofeng
The relationship between the morphology and the properties of aromatic polyamide 1313 (Nomex) fiber is studied systematically. Methods for increasing the crystallinity and orientation of Nomex fiber are discussed on the basis of a crystal structure model. The triclinic lattice form and the desired properties can be obtained by keeping the temperature of the heat treatment higher than that used for maximum crystallization rate and by using a higher drawing ratio. Experiments have confirmed these conclusions. The batch products have obtained the desired properties.<>
{"title":"The influence of the morphology on properties of aromatic polyamide fibre","authors":"G. Liang-yu, Liu Yaonan, Xi Baofeng","doi":"10.1109/ICPADM.1991.172304","DOIUrl":"https://doi.org/10.1109/ICPADM.1991.172304","url":null,"abstract":"The relationship between the morphology and the properties of aromatic polyamide 1313 (Nomex) fiber is studied systematically. Methods for increasing the crystallinity and orientation of Nomex fiber are discussed on the basis of a crystal structure model. The triclinic lattice form and the desired properties can be obtained by keeping the temperature of the heat treatment higher than that used for maximum crystallization rate and by using a higher drawing ratio. Experiments have confirmed these conclusions. The batch products have obtained the desired properties.<<ETX>>","PeriodicalId":6450,"journal":{"name":"[1991] Proceedings of the 3rd International Conference on Properties and Applications of Dielectric Materials","volume":"153 1","pages":"1238-1241 vol.2"},"PeriodicalIF":0.0,"publicationDate":"1991-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88434466","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1991-07-08DOI: 10.1109/ICPADM.1991.172272
D. Allan, C. Jones, B. Sharp
The authors describe practical insulation life assessment techniques developed within the Queensland Electricity Commission for the estimation of remaining useful life of its large power transformers. Novel aspects of the technique are: (i) the use of a database of oil test results for statistical analysis of several aging indicators, to derive an 'insulation age' for the transformer; (ii) the extraction of paper samples from in-situ transformers for analysis of their degree of polymerization (DP); and (iii) the application of appropriate life models to typical power transformers to determine remaining life on a probabilistic basis. These analyses are supported by studies on dismantled large power transformers at the Commission's workshop, to determine the DP profile through typical transformers. From this, relationships are estimated between the DP at hot spots in the transformer and that obtained at convenient sampling locations.<>
{"title":"Studies of the condition of insulation in aged power transformers. 1. Insulation condition and remnant life assessments for in-service units","authors":"D. Allan, C. Jones, B. Sharp","doi":"10.1109/ICPADM.1991.172272","DOIUrl":"https://doi.org/10.1109/ICPADM.1991.172272","url":null,"abstract":"The authors describe practical insulation life assessment techniques developed within the Queensland Electricity Commission for the estimation of remaining useful life of its large power transformers. Novel aspects of the technique are: (i) the use of a database of oil test results for statistical analysis of several aging indicators, to derive an 'insulation age' for the transformer; (ii) the extraction of paper samples from in-situ transformers for analysis of their degree of polymerization (DP); and (iii) the application of appropriate life models to typical power transformers to determine remaining life on a probabilistic basis. These analyses are supported by studies on dismantled large power transformers at the Commission's workshop, to determine the DP profile through typical transformers. From this, relationships are estimated between the DP at hot spots in the transformer and that obtained at convenient sampling locations.<<ETX>>","PeriodicalId":6450,"journal":{"name":"[1991] Proceedings of the 3rd International Conference on Properties and Applications of Dielectric Materials","volume":"38 1","pages":"1116-1119 vol.2"},"PeriodicalIF":0.0,"publicationDate":"1991-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77343851","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1991-07-08DOI: 10.1109/ICPADM.1991.172155
T. Ishida, Y. Mizuno, M. Nagao, M. Kosaki
The authors developed a personal-computer-aided partial discharge analyzing system for SPMD (swarming pulsed microdischarge) measurement. The system has two detection methods for partial discharge measurement: a conventional pulse charge method and a balanced Lissajous figure method. The former failed to detect SPMD due to the sensitivity limit of the detector, while the latter integrated all charges including SPMD per half cycle. Therefore, the difference between the charge integrals of partial discharges per half cycle measured by these two methods must be a good measure of SPMD. Based on this idea, a new parameter, the SPMD ratio, was introduced. Using the developed system, partial discharge characteristics were studied for the CIGRE method II specimen with internal void in order to examine the factor in the presence of SPMD. The results show that the magnitude of applied voltage, its frequency, and roughness of the void surface affect the appearance of SPMD.<>
{"title":"Development and application of partial discharge analyzing system for swarming pulsive microdischarges","authors":"T. Ishida, Y. Mizuno, M. Nagao, M. Kosaki","doi":"10.1109/ICPADM.1991.172155","DOIUrl":"https://doi.org/10.1109/ICPADM.1991.172155","url":null,"abstract":"The authors developed a personal-computer-aided partial discharge analyzing system for SPMD (swarming pulsed microdischarge) measurement. The system has two detection methods for partial discharge measurement: a conventional pulse charge method and a balanced Lissajous figure method. The former failed to detect SPMD due to the sensitivity limit of the detector, while the latter integrated all charges including SPMD per half cycle. Therefore, the difference between the charge integrals of partial discharges per half cycle measured by these two methods must be a good measure of SPMD. Based on this idea, a new parameter, the SPMD ratio, was introduced. Using the developed system, partial discharge characteristics were studied for the CIGRE method II specimen with internal void in order to examine the factor in the presence of SPMD. The results show that the magnitude of applied voltage, its frequency, and roughness of the void surface affect the appearance of SPMD.<<ETX>>","PeriodicalId":6450,"journal":{"name":"[1991] Proceedings of the 3rd International Conference on Properties and Applications of Dielectric Materials","volume":"1 1","pages":"676-679 vol.2"},"PeriodicalIF":0.0,"publicationDate":"1991-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86978033","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1991-07-08DOI: 10.1109/ICPADM.1991.172062
Y. Mizuno, T. Ohe, K. Nomizu, Hideo Muneyasu, M. Nagao, M. Kosaki, N. Shimizu, K. Horii
The mechanical and electrical properties of ethylene propylene rubber (EPR) pieces were made in comparison with polyethylene (PE) in the cryogenic temperature region to examine the possibility for use in solid electrical insulation material of superconducting cables. The mechanical properties of EPR are preferable to those of PE because of its low shrinkage. The electric strength and dielectric loss tangent of EPR are comparable to those of PE at liquid helium temperature. Based on these encouraging results, an extruded EPR-insulated cable was fabricated and its 15 m length was cooled down to liquid helium temperature successfully. A partial discharge experiment at the temperature showed good electrical characteristics.<>
{"title":"Evaluation of ethylene propylene rubber as an electrical insulation material of superconducting cable","authors":"Y. Mizuno, T. Ohe, K. Nomizu, Hideo Muneyasu, M. Nagao, M. Kosaki, N. Shimizu, K. Horii","doi":"10.1109/ICPADM.1991.172062","DOIUrl":"https://doi.org/10.1109/ICPADM.1991.172062","url":null,"abstract":"The mechanical and electrical properties of ethylene propylene rubber (EPR) pieces were made in comparison with polyethylene (PE) in the cryogenic temperature region to examine the possibility for use in solid electrical insulation material of superconducting cables. The mechanical properties of EPR are preferable to those of PE because of its low shrinkage. The electric strength and dielectric loss tangent of EPR are comparable to those of PE at liquid helium temperature. Based on these encouraging results, an extruded EPR-insulated cable was fabricated and its 15 m length was cooled down to liquid helium temperature successfully. A partial discharge experiment at the temperature showed good electrical characteristics.<<ETX>>","PeriodicalId":6450,"journal":{"name":"[1991] Proceedings of the 3rd International Conference on Properties and Applications of Dielectric Materials","volume":"18 1","pages":"317-321 vol.1"},"PeriodicalIF":0.0,"publicationDate":"1991-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85665631","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1991-07-08DOI: 10.1109/ICPADM.1991.172300
Z. Yingsuo, Bai Yi
It has been found that the accuracy of the constant slope (CS) method was +or-16.6 degrees C as compared with conventional aging (CA) (its standard deviation of error Delta t, S=8.3 degrees C). A scientific approach to the study of the CS method is presented here. It is noted that this method possesses a certain investigation value, and may be able to help one understand the change law of activation energy in CA, as well as present the complex relation between various rapid methods in order to explore the possibility of developing a higher-accuracy and really practical rapid method.<>
{"title":"A study on constant slope method for rapid thermal endurance tests of dielectrics","authors":"Z. Yingsuo, Bai Yi","doi":"10.1109/ICPADM.1991.172300","DOIUrl":"https://doi.org/10.1109/ICPADM.1991.172300","url":null,"abstract":"It has been found that the accuracy of the constant slope (CS) method was +or-16.6 degrees C as compared with conventional aging (CA) (its standard deviation of error Delta t, S=8.3 degrees C). A scientific approach to the study of the CS method is presented here. It is noted that this method possesses a certain investigation value, and may be able to help one understand the change law of activation energy in CA, as well as present the complex relation between various rapid methods in order to explore the possibility of developing a higher-accuracy and really practical rapid method.<<ETX>>","PeriodicalId":6450,"journal":{"name":"[1991] Proceedings of the 3rd International Conference on Properties and Applications of Dielectric Materials","volume":"65 1","pages":"1225-1228 vol.2"},"PeriodicalIF":0.0,"publicationDate":"1991-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91216433","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1991-07-08DOI: 10.1109/ICPADM.1991.172136
A. Kawamoto, Y. Suzuoki, T. Ikejiri, T. Mizutani, M. Ieda
The effects of the epoxy-resin interface on electronic conduction were studied by using photocurrent and thermally stimulated current techniques. The electrical properties of epoxy-filler composites are greatly affected by the interfaces in various ways depending on applied field, temperature, carrier species, and mechanical stress. At low temperature, electronic carriers transported from the epoxy layer in epoxy-alumina composites can pass through the epoxy-alumina interface and move in the alumina bulk, increasing the conduction current in the alumina, but they are accumulated at the interface and lead to interfacial polarization at room temperature. At low fields and low temperature, electronic carriers from the alumina layer can pass through the epoxy-alumina interface and increase the conduction current in the epoxy resin, but they are accumulated at the interface at high field and the conduction is explained by the Maxwell-Wagner model. At room temperature, electronic carriers from the alumina layer are blocked by the potential barrier at the interface. However, electronic carriers from the epoxy layer can pass through the epoxy-silica interface and increase the conduction current in the silica at low and room temperature.<>
{"title":"Effects of interface on electrical conduction in epoxy resin composites","authors":"A. Kawamoto, Y. Suzuoki, T. Ikejiri, T. Mizutani, M. Ieda","doi":"10.1109/ICPADM.1991.172136","DOIUrl":"https://doi.org/10.1109/ICPADM.1991.172136","url":null,"abstract":"The effects of the epoxy-resin interface on electronic conduction were studied by using photocurrent and thermally stimulated current techniques. The electrical properties of epoxy-filler composites are greatly affected by the interfaces in various ways depending on applied field, temperature, carrier species, and mechanical stress. At low temperature, electronic carriers transported from the epoxy layer in epoxy-alumina composites can pass through the epoxy-alumina interface and move in the alumina bulk, increasing the conduction current in the alumina, but they are accumulated at the interface and lead to interfacial polarization at room temperature. At low fields and low temperature, electronic carriers from the alumina layer can pass through the epoxy-alumina interface and increase the conduction current in the epoxy resin, but they are accumulated at the interface at high field and the conduction is explained by the Maxwell-Wagner model. At room temperature, electronic carriers from the alumina layer are blocked by the potential barrier at the interface. However, electronic carriers from the epoxy layer can pass through the epoxy-silica interface and increase the conduction current in the silica at low and room temperature.<<ETX>>","PeriodicalId":6450,"journal":{"name":"[1991] Proceedings of the 3rd International Conference on Properties and Applications of Dielectric Materials","volume":"19 1","pages":"619-622 vol.1"},"PeriodicalIF":0.0,"publicationDate":"1991-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88642365","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1991-07-08DOI: 10.1109/ICPADM.1991.172129
M. Ieda, H. Karner, Y. Suzuoka
The authors summarize interfacial phenomena involved mainly in solid insulating systems. Emphasis is placed on charge injection and accumulation, electrochemical reaction, carrier transport, carrier trapping, mechanical stress, swelling, and streaming electrification. It is pointed out that various kinds of interfacial effects manifest themselves in various ways in affect the electrical properties of composites. The discussion is limited to interfaces inside solids or solid-liquid composites.<>
{"title":"Fundamental aspects of interfacial phenomena in solid insulating systems","authors":"M. Ieda, H. Karner, Y. Suzuoka","doi":"10.1109/ICPADM.1991.172129","DOIUrl":"https://doi.org/10.1109/ICPADM.1991.172129","url":null,"abstract":"The authors summarize interfacial phenomena involved mainly in solid insulating systems. Emphasis is placed on charge injection and accumulation, electrochemical reaction, carrier transport, carrier trapping, mechanical stress, swelling, and streaming electrification. It is pointed out that various kinds of interfacial effects manifest themselves in various ways in affect the electrical properties of composites. The discussion is limited to interfaces inside solids or solid-liquid composites.<<ETX>>","PeriodicalId":6450,"journal":{"name":"[1991] Proceedings of the 3rd International Conference on Properties and Applications of Dielectric Materials","volume":"19 1","pages":"598-603 vol.1"},"PeriodicalIF":0.0,"publicationDate":"1991-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88808752","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1991-07-08DOI: 10.1109/ICPADM.1991.172029
M. Fukuzawa, I. Mitsumasa
The authors measured the TSC (thermally stimulated current) and TSSP (thermally stimulated surface potential) on low-density polyethylene (LDPE) films sandwiched between needle electrodes and plane electrodes, and then evaluated the space charges. To confirm that injection occurs from needle electrodes and that injection space charges are trapped around the needle tips, the experiments were carried out with different numbers of needle electrodes, e.g. 20. Finally, the authors examined the influence of the space charges on the mechanisms of treeing in an LDPE film by measuring the inception voltage of treeing in the film.<>
{"title":"Thermally stimulated electrical measurement of an LDPE film stressed under a nonuniform electric field: influence of the space charge on treeing","authors":"M. Fukuzawa, I. Mitsumasa","doi":"10.1109/ICPADM.1991.172029","DOIUrl":"https://doi.org/10.1109/ICPADM.1991.172029","url":null,"abstract":"The authors measured the TSC (thermally stimulated current) and TSSP (thermally stimulated surface potential) on low-density polyethylene (LDPE) films sandwiched between needle electrodes and plane electrodes, and then evaluated the space charges. To confirm that injection occurs from needle electrodes and that injection space charges are trapped around the needle tips, the experiments were carried out with different numbers of needle electrodes, e.g. 20. Finally, the authors examined the influence of the space charges on the mechanisms of treeing in an LDPE film by measuring the inception voltage of treeing in the film.<<ETX>>","PeriodicalId":6450,"journal":{"name":"[1991] Proceedings of the 3rd International Conference on Properties and Applications of Dielectric Materials","volume":"26 1","pages":"121-126 vol.1"},"PeriodicalIF":0.0,"publicationDate":"1991-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88815173","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1991-07-08DOI: 10.1109/ICPADM.1991.172284
M. Nagao, K. Takano, Y. Mizuno, M. Kosaki
The intrinsic AC electrical breakdown of low-density polyethylene film was studied above room temperature under the partial-discharge-free condition using McKeown-type specimens. The dependence of AC electric strength on the temperature, the rise rate, and the frequency of applied electric field suggests that, under AC voltage application, the thermal process might be dominant rather than the electronic process. The results are also discussed in terms of the dependence of the high-field dielectric dissipation factor on the applied electric field and the voltage application time.<>
{"title":"Intrinsic AC breakdown of low-density polyethylene film above room temperature","authors":"M. Nagao, K. Takano, Y. Mizuno, M. Kosaki","doi":"10.1109/ICPADM.1991.172284","DOIUrl":"https://doi.org/10.1109/ICPADM.1991.172284","url":null,"abstract":"The intrinsic AC electrical breakdown of low-density polyethylene film was studied above room temperature under the partial-discharge-free condition using McKeown-type specimens. The dependence of AC electric strength on the temperature, the rise rate, and the frequency of applied electric field suggests that, under AC voltage application, the thermal process might be dominant rather than the electronic process. The results are also discussed in terms of the dependence of the high-field dielectric dissipation factor on the applied electric field and the voltage application time.<<ETX>>","PeriodicalId":6450,"journal":{"name":"[1991] Proceedings of the 3rd International Conference on Properties and Applications of Dielectric Materials","volume":"34 1","pages":"1165-1168 vol.2"},"PeriodicalIF":0.0,"publicationDate":"1991-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86498148","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1991-07-08DOI: 10.1109/ICPADM.1991.172208
S. Ochiai, H. Iwasaki, M. Ieda, T. Mizutani
The electrical properties and oil/polymer interaction for an alkylbenzene/polypropylene (PP) composite insulator with chemically etched polymer (PPc) were investigated with the thermally stimulated current (TSC), surface roughness, and FT-IR (Fourier transform infrared) methods. The etched rough surface was obtained by the dissolution of the amorphous part of the PP surface in sulfuric acid. The TSC obtained on an oil/PPc specimen has four clear peaks. The comparison in TSC between oil/PP (virgin) and oil/PPc revealed that impurities in PP exist near the surface of PP and that PPc has shallower ion traps than PP. It is concluded that the wettability of the polymer surface was improved by the chemical etching. In other words, the chemical etching of the polymer surface produces an optimum polymer surface for the impregnation of oil.<>
{"title":"TSC of oil/polymer film composite insulator with chemically etched polymer film","authors":"S. Ochiai, H. Iwasaki, M. Ieda, T. Mizutani","doi":"10.1109/ICPADM.1991.172208","DOIUrl":"https://doi.org/10.1109/ICPADM.1991.172208","url":null,"abstract":"The electrical properties and oil/polymer interaction for an alkylbenzene/polypropylene (PP) composite insulator with chemically etched polymer (PPc) were investigated with the thermally stimulated current (TSC), surface roughness, and FT-IR (Fourier transform infrared) methods. The etched rough surface was obtained by the dissolution of the amorphous part of the PP surface in sulfuric acid. The TSC obtained on an oil/PPc specimen has four clear peaks. The comparison in TSC between oil/PP (virgin) and oil/PPc revealed that impurities in PP exist near the surface of PP and that PPc has shallower ion traps than PP. It is concluded that the wettability of the polymer surface was improved by the chemical etching. In other words, the chemical etching of the polymer surface produces an optimum polymer surface for the impregnation of oil.<<ETX>>","PeriodicalId":6450,"journal":{"name":"[1991] Proceedings of the 3rd International Conference on Properties and Applications of Dielectric Materials","volume":"26 1","pages":"875-878 vol.2"},"PeriodicalIF":0.0,"publicationDate":"1991-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89412859","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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