Pub Date : 1994-07-03DOI: 10.1109/ICPADM.1994.413981
G. J. Pratt, M.J.A. Smith
Contour maps of real relative permittivity and dielectric loss tangent over the ranges 0.1 Hz to 3 MHz and -175/spl deg/C to +145/spl deg/C for a commercial poly-/spl beta/-hydroxybutyratehydroxyvalerate (PHBV) copolymer reveal four principal features. The region of loss associated with each feature occurs at a lower temperature than in the equivalent PHB homopolymer. Possible sources are suggested for the losses.<>
{"title":"Dielectric spectroscopy of a commercial polyhydroxybutyratehydroxyvalerate copolymer","authors":"G. J. Pratt, M.J.A. Smith","doi":"10.1109/ICPADM.1994.413981","DOIUrl":"https://doi.org/10.1109/ICPADM.1994.413981","url":null,"abstract":"Contour maps of real relative permittivity and dielectric loss tangent over the ranges 0.1 Hz to 3 MHz and -175/spl deg/C to +145/spl deg/C for a commercial poly-/spl beta/-hydroxybutyratehydroxyvalerate (PHBV) copolymer reveal four principal features. The region of loss associated with each feature occurs at a lower temperature than in the equivalent PHB homopolymer. Possible sources are suggested for the losses.<<ETX>>","PeriodicalId":331058,"journal":{"name":"Proceedings of 1994 4th International Conference on Properties and Applications of Dielectric Materials (ICPADM)","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123918150","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 : 1994-07-03DOI: 10.1109/ICPADM.1994.413918
R. Hegerberg, B. Sanden
The impulse breakdown strength of XLPE samples made of cable-grade material poled at 35 kV/mm DC has been found to be reduced by approximately 35 kV/mm for the aiding case compared to the opposing polarity. The internal space charge distribution is, however, found to be reasonably homogeneous and consisting of negative net charge, seemingly contradicting the commonly assumed explanation of the polarity dependence effect, based on the occurrence of heterocharge accumulation in the material during the pre-stress period. The present results indicate that the local field strength near the anode controls the breakdown, but no hypothesis supporting such an effect is available.<>
{"title":"Space charge and impulse breakdown strength in XLPE","authors":"R. Hegerberg, B. Sanden","doi":"10.1109/ICPADM.1994.413918","DOIUrl":"https://doi.org/10.1109/ICPADM.1994.413918","url":null,"abstract":"The impulse breakdown strength of XLPE samples made of cable-grade material poled at 35 kV/mm DC has been found to be reduced by approximately 35 kV/mm for the aiding case compared to the opposing polarity. The internal space charge distribution is, however, found to be reasonably homogeneous and consisting of negative net charge, seemingly contradicting the commonly assumed explanation of the polarity dependence effect, based on the occurrence of heterocharge accumulation in the material during the pre-stress period. The present results indicate that the local field strength near the anode controls the breakdown, but no hypothesis supporting such an effect is available.<<ETX>>","PeriodicalId":331058,"journal":{"name":"Proceedings of 1994 4th International Conference on Properties and Applications of Dielectric Materials (ICPADM)","volume":"135 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121291782","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 : 1994-07-03DOI: 10.1109/ICPADM.1994.414008
G. Touchard, H. Romat, P.O. Grimaud, S. Watanabe
This paper deals with the diffuse layer present at the interface between a liquid and a solid in a cylindrical geometry. After having set out the governing equations of the phenomenon in the most general case, we present the real solution, asymptotic solutions and an approach solution. The first one has been obtained numerically and the last one comes from an empirical approach. In the last part of the paper we compare the different profiles of space charge density obtained by the different ways which are mentioned above. We also compare the corresponding convected mean space charge densities in terms of the radius of the pipe and the space charge density at the wall. This leads to determination of the cases in which we can use the empirical solution which is of a great interest for industry.<>
{"title":"Solutions for the electrical interfacial problem between a dielectric liquid and a metallic wall: applications to industry","authors":"G. Touchard, H. Romat, P.O. Grimaud, S. Watanabe","doi":"10.1109/ICPADM.1994.414008","DOIUrl":"https://doi.org/10.1109/ICPADM.1994.414008","url":null,"abstract":"This paper deals with the diffuse layer present at the interface between a liquid and a solid in a cylindrical geometry. After having set out the governing equations of the phenomenon in the most general case, we present the real solution, asymptotic solutions and an approach solution. The first one has been obtained numerically and the last one comes from an empirical approach. In the last part of the paper we compare the different profiles of space charge density obtained by the different ways which are mentioned above. We also compare the corresponding convected mean space charge densities in terms of the radius of the pipe and the space charge density at the wall. This leads to determination of the cases in which we can use the empirical solution which is of a great interest for industry.<<ETX>>","PeriodicalId":331058,"journal":{"name":"Proceedings of 1994 4th International Conference on Properties and Applications of Dielectric Materials (ICPADM)","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124299194","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 : 1994-07-03DOI: 10.1109/ICPADM.1994.414156
C.F. Jones, A. Mayne
A major utilities' (Queensland Electricity Company) experiences with moisture determination in electrical insulation via the coulometric and titrimetric Karl Fischer technique are revealed. The importance of maintaining confidence in the reliability of this determination in relation to electrical plant contractual acceptance, maintenance and overhaul is discussed and sources of error in the overall determination of insulation dryness are examined. Major sources of error in moisture determinations are the sampling process, subsequent sample handling, inadequate knowledge of material composition and generally unrecognised characteristics of the Karl Fischer technique. The paper describes the approach taken in the authors organisation to reduce such errors in the determination of the relative humidity of insulation systems. One approach to a methodology for identification and measurement of accuracy, precision and bias is also presented.<>
{"title":"Application and limitations of the Karl Fischer technique of moisture analysis in electrical plant insulation","authors":"C.F. Jones, A. Mayne","doi":"10.1109/ICPADM.1994.414156","DOIUrl":"https://doi.org/10.1109/ICPADM.1994.414156","url":null,"abstract":"A major utilities' (Queensland Electricity Company) experiences with moisture determination in electrical insulation via the coulometric and titrimetric Karl Fischer technique are revealed. The importance of maintaining confidence in the reliability of this determination in relation to electrical plant contractual acceptance, maintenance and overhaul is discussed and sources of error in the overall determination of insulation dryness are examined. Major sources of error in moisture determinations are the sampling process, subsequent sample handling, inadequate knowledge of material composition and generally unrecognised characteristics of the Karl Fischer technique. The paper describes the approach taken in the authors organisation to reduce such errors in the determination of the relative humidity of insulation systems. One approach to a methodology for identification and measurement of accuracy, precision and bias is also presented.<<ETX>>","PeriodicalId":331058,"journal":{"name":"Proceedings of 1994 4th International Conference on Properties and Applications of Dielectric Materials (ICPADM)","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127683803","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 : 1994-07-03DOI: 10.1109/ICPADM.1994.413977
S. Ochiai, T. Kato, A. Maeda, M. Ieda, T. Mizutani
PTFE (polytetrafluoroethylene) film is an excellent insulating material. It also has good hydrophobicity and superior chemical stability. But it is difficult to make good thin films (thickness<10 /spl mu/m). We have obtained ultra thin film (thickness<1 /spl mu/m) with the RF sputtering method. The electric strength of 7.9 nm-thick film is about 7 MV/cm which is much higher than that of a conventional PTFE film. The conduction currents may be Schottky type in a high field region. The contact angle of an thin PTFE film is the almost same as that of a conventional PTFE film and it is 100/spl deg/ at a room temperature. This also means that the morphology of the ultra thin PTFE film (thin PTFE film) is similar to that a conventional PTFE film. The results of the electron spectroscopy for chemical analysis (ESCA) and the X ray diffraction revealed the thin PTFE film is an amorphous rich compound polymer.<>
{"title":"Morphology and electrical properties of ultra thin PTFE film prepared with RF sputtering","authors":"S. Ochiai, T. Kato, A. Maeda, M. Ieda, T. Mizutani","doi":"10.1109/ICPADM.1994.413977","DOIUrl":"https://doi.org/10.1109/ICPADM.1994.413977","url":null,"abstract":"PTFE (polytetrafluoroethylene) film is an excellent insulating material. It also has good hydrophobicity and superior chemical stability. But it is difficult to make good thin films (thickness<10 /spl mu/m). We have obtained ultra thin film (thickness<1 /spl mu/m) with the RF sputtering method. The electric strength of 7.9 nm-thick film is about 7 MV/cm which is much higher than that of a conventional PTFE film. The conduction currents may be Schottky type in a high field region. The contact angle of an thin PTFE film is the almost same as that of a conventional PTFE film and it is 100/spl deg/ at a room temperature. This also means that the morphology of the ultra thin PTFE film (thin PTFE film) is similar to that a conventional PTFE film. The results of the electron spectroscopy for chemical analysis (ESCA) and the X ray diffraction revealed the thin PTFE film is an amorphous rich compound polymer.<<ETX>>","PeriodicalId":331058,"journal":{"name":"Proceedings of 1994 4th International Conference on Properties and Applications of Dielectric Materials (ICPADM)","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126453028","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 : 1994-07-03DOI: 10.1109/ICPADM.1994.414116
P. Scarpa, A. Svatik, D. Das-Gupta
The dielectric spectroscopy of the unaged and AC aged (6 kV/mm, 2.5 kHz, 0.1N NaCl, 69 hours) LDPE samples with three different experimental conditions (i.e., at room temperature, at room temperature after additional DC poling at 70/spl deg/C with 2 kV/mm for 1 hour followed by cooling down to room temperature in the presence of the field, and at 70/spl deg/C), are presented. It is shown that a parallel combination of the "universal relaxation law" and "low frequency dispersion" relaxation can account for the observed behaviour. The observed changes in the low frequency range (10/sup -5/Hz to 10/sup -2/Hz) appear to be most significant regarding the electrical ageing.<>
{"title":"Dielectric relaxation behaviour of electrically (AC) aged polyethylene in humid environment","authors":"P. Scarpa, A. Svatik, D. Das-Gupta","doi":"10.1109/ICPADM.1994.414116","DOIUrl":"https://doi.org/10.1109/ICPADM.1994.414116","url":null,"abstract":"The dielectric spectroscopy of the unaged and AC aged (6 kV/mm, 2.5 kHz, 0.1N NaCl, 69 hours) LDPE samples with three different experimental conditions (i.e., at room temperature, at room temperature after additional DC poling at 70/spl deg/C with 2 kV/mm for 1 hour followed by cooling down to room temperature in the presence of the field, and at 70/spl deg/C), are presented. It is shown that a parallel combination of the \"universal relaxation law\" and \"low frequency dispersion\" relaxation can account for the observed behaviour. The observed changes in the low frequency range (10/sup -5/Hz to 10/sup -2/Hz) appear to be most significant regarding the electrical ageing.<<ETX>>","PeriodicalId":331058,"journal":{"name":"Proceedings of 1994 4th International Conference on Properties and Applications of Dielectric Materials (ICPADM)","volume":"146 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132347734","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 : 1994-07-03DOI: 10.1109/ICPADM.1994.414133
T. Hara, L.F.L. Vianna, E. E. Nachvalger, E. Gonçalves
The importance of "Governador Bento Munhoz da Rocha Neto-GBM Power Plant", its time in service and its operating conditions render it necessary to assess the generators' remaining service life. It was also considered appropriate to review the operating conditions relating them with the economical aspects involved. Based on a model proposed by H. Yoshida and K. Uemoto (1986) and in Copel's experience, this paper shows not only the elapsed costs of today's operation planner but also the cost of insulation degradation due to the number of starts and stops. It proposes a new operating condition and suggests insulation tests and maintenance precautions for equipment.<>
“governor Bento Munhoz da Rocha Neto-GBM电厂”的重要性、其运行时间和运行条件使得有必要评估发电机的剩余使用寿命。还认为应当从所涉经济方面审查与它们有关的作业条件。基于H. Yoshida和K. Uemoto(1986)提出的模型以及Copel的经验，本文不仅显示了当今运行计划的消耗成本，还显示了由于启动和停止次数而导致的绝缘退化成本。它提出了一种新的操作条件，并建议了设备的绝缘测试和维护注意事项。
{"title":"Valuation about remaining service life of GBM hydraulic power plant units technical and economical aspects","authors":"T. Hara, L.F.L. Vianna, E. E. Nachvalger, E. Gonçalves","doi":"10.1109/ICPADM.1994.414133","DOIUrl":"https://doi.org/10.1109/ICPADM.1994.414133","url":null,"abstract":"The importance of \"Governador Bento Munhoz da Rocha Neto-GBM Power Plant\", its time in service and its operating conditions render it necessary to assess the generators' remaining service life. It was also considered appropriate to review the operating conditions relating them with the economical aspects involved. Based on a model proposed by H. Yoshida and K. Uemoto (1986) and in Copel's experience, this paper shows not only the elapsed costs of today's operation planner but also the cost of insulation degradation due to the number of starts and stops. It proposes a new operating condition and suggests insulation tests and maintenance precautions for equipment.<<ETX>>","PeriodicalId":331058,"journal":{"name":"Proceedings of 1994 4th International Conference on Properties and Applications of Dielectric Materials (ICPADM)","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131043931","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 : 1994-07-03DOI: 10.1109/ICPADM.1994.413995
W. Choi, Chung-hyeok Kim, Joon-Ung Lee, Choon-Bae Park, Sung-ill Lee
The dielectric properties and the microstructure of (Sr.Ca)TiO/sub 3/-based boundary layer (BL) capacitor materials were investigated. (Sr.Ca)TiO/sub 3/-based compositions were fired at 1350/spl deg/C in a N/sub 2/ atmosphere to get the base semiconducting ceramics. The metal oxides of CuO were printed on the semiconducting ceramics and fired at 1200/spl deg/C for the subsequent grain boundary diffusion. The grain size of the semiconducting ceramics was 20/spl sim/40 /spl mu/m and the apparent permittivity of the resulting material varied between 2/spl times/10/sup 4/ and 3/spl times/10/sup 4/.<>
{"title":"Dielectric properties and microstructure of (Sr.Ca)TiO/sub 3/-based boundary layer capacitor materials","authors":"W. Choi, Chung-hyeok Kim, Joon-Ung Lee, Choon-Bae Park, Sung-ill Lee","doi":"10.1109/ICPADM.1994.413995","DOIUrl":"https://doi.org/10.1109/ICPADM.1994.413995","url":null,"abstract":"The dielectric properties and the microstructure of (Sr.Ca)TiO/sub 3/-based boundary layer (BL) capacitor materials were investigated. (Sr.Ca)TiO/sub 3/-based compositions were fired at 1350/spl deg/C in a N/sub 2/ atmosphere to get the base semiconducting ceramics. The metal oxides of CuO were printed on the semiconducting ceramics and fired at 1200/spl deg/C for the subsequent grain boundary diffusion. The grain size of the semiconducting ceramics was 20/spl sim/40 /spl mu/m and the apparent permittivity of the resulting material varied between 2/spl times/10/sup 4/ and 3/spl times/10/sup 4/.<<ETX>>","PeriodicalId":331058,"journal":{"name":"Proceedings of 1994 4th International Conference on Properties and Applications of Dielectric Materials (ICPADM)","volume":"27 3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133417693","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 : 1994-07-03DOI: 10.1109/ICPADM.1994.414077
Wang Changchang, Wang Zhongdong, L. Fuqi, Jin Xianhe
To suppress interference is a critical technique of online partial discharge monitoring for power equipment insulation. They can be divided into two types: periodical and impulse interference according to their signal characteristic. Different anti-interference techniques can then be chosen to suppress them separately. This paper describes various anti-interference techniques which have been developed recently and their actual effect on online partial discharge monitoring. The above techniques include a combined filter, a digital filter, a differential system and a pulse discrimination system. This paper presents some other anti-interference ideas which are satisfied for online partial discharge monitoring.<>
{"title":"Anti-interference techniques used for on-line partial discharge monitoring","authors":"Wang Changchang, Wang Zhongdong, L. Fuqi, Jin Xianhe","doi":"10.1109/ICPADM.1994.414077","DOIUrl":"https://doi.org/10.1109/ICPADM.1994.414077","url":null,"abstract":"To suppress interference is a critical technique of online partial discharge monitoring for power equipment insulation. They can be divided into two types: periodical and impulse interference according to their signal characteristic. Different anti-interference techniques can then be chosen to suppress them separately. This paper describes various anti-interference techniques which have been developed recently and their actual effect on online partial discharge monitoring. The above techniques include a combined filter, a digital filter, a differential system and a pulse discrimination system. This paper presents some other anti-interference ideas which are satisfied for online partial discharge monitoring.<<ETX>>","PeriodicalId":331058,"journal":{"name":"Proceedings of 1994 4th International Conference on Properties and Applications of Dielectric Materials (ICPADM)","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132179324","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 : 1994-07-03DOI: 10.1109/ICPADM.1994.413934
Y. Qiu, Y.P. Feng
Dielectric strength of the SF/sub 6//N/sub 2/ gas mixture in a uniform field can be calculated using a simple method assuming there is no interaction between the different component gas molecules. However, to calculate the dielectric strength of the gas mixture in a practical gas-insulated system, both the electrode curvature factor and the electrode surface roughness factor should be taken into account. This paper presents the electrode curvature factors for SF/sub 6//N/sub 2/ in a coaxial electrode system and in a concentric spherical electrode system, and reports the effect of electrode surface roughness on breakdown in the SF/sub 6//N/sub 2/ gas mixture.<>
{"title":"Calculation of dielectric strength of the SF/sub 6//N/sub 2/ gas mixture in macroscopically and microscopically non-uniform fields","authors":"Y. Qiu, Y.P. Feng","doi":"10.1109/ICPADM.1994.413934","DOIUrl":"https://doi.org/10.1109/ICPADM.1994.413934","url":null,"abstract":"Dielectric strength of the SF/sub 6//N/sub 2/ gas mixture in a uniform field can be calculated using a simple method assuming there is no interaction between the different component gas molecules. However, to calculate the dielectric strength of the gas mixture in a practical gas-insulated system, both the electrode curvature factor and the electrode surface roughness factor should be taken into account. This paper presents the electrode curvature factors for SF/sub 6//N/sub 2/ in a coaxial electrode system and in a concentric spherical electrode system, and reports the effect of electrode surface roughness on breakdown in the SF/sub 6//N/sub 2/ gas mixture.<<ETX>>","PeriodicalId":331058,"journal":{"name":"Proceedings of 1994 4th International Conference on Properties and Applications of Dielectric Materials (ICPADM)","volume":"345 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1994-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115229396","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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