Pub Date : 1989-10-29DOI: 10.1109/CEIDP.1989.69569
J. Sheshakamal, J. Cross
The authors present results of an investigation of the influence of inherent and added impurities in transformer oils on electrohydrodynamic (EHD) instabilities. All the test samples were subjected to a voltage step applied to parallel plane electrodes. Two of the test liquids were sampled from in-service transformers. The magnitude of change in the current in transformer oils after filtration (0.45 mu m) was three to five times larger than the change caused by the addition of conducting particles. The transformer oil aged in service for longer duration showed higher EHD current and flow which were associated with higher particulate concentration and conductivity. The measurement of AC breakdown strength was less reflective of the extent of oil degradation as compared to transient current response. The space charge density variation that causes EHD instability in insulating oils depends on both suspended and dissolved impurities.<>
{"title":"The influence of impurities on electrohydrodynamic motion in insulating oils","authors":"J. Sheshakamal, J. Cross","doi":"10.1109/CEIDP.1989.69569","DOIUrl":"https://doi.org/10.1109/CEIDP.1989.69569","url":null,"abstract":"The authors present results of an investigation of the influence of inherent and added impurities in transformer oils on electrohydrodynamic (EHD) instabilities. All the test samples were subjected to a voltage step applied to parallel plane electrodes. Two of the test liquids were sampled from in-service transformers. The magnitude of change in the current in transformer oils after filtration (0.45 mu m) was three to five times larger than the change caused by the addition of conducting particles. The transformer oil aged in service for longer duration showed higher EHD current and flow which were associated with higher particulate concentration and conductivity. The measurement of AC breakdown strength was less reflective of the extent of oil degradation as compared to transient current response. The space charge density variation that causes EHD instability in insulating oils depends on both suspended and dissolved impurities.<<ETX>>","PeriodicalId":10719,"journal":{"name":"Conference on Electrical Insulation and Dielectric Phenomena,","volume":"35 1","pages":"338-345"},"PeriodicalIF":0.0,"publicationDate":"1989-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79164973","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 : 1989-10-29DOI: 10.1109/CEIDP.1989.69585
C. Cooke, K. Wright, N. Takasu, J. Bernstein, E. Gollin
The authors consider the use of charges implanted by means of energetic electron beams to create known charge distributions for calibration purposes. For a successful calibration the reference charge samples should provide a well-defined charge, including location, distribution, and magnitude (and sign). Although these parts of the calibration may be accomplished with different samples, it is preferable for simplicity and accuracy to include these in a single sample. The e-beam implanted charge distributions have been found to achieve the needed reference charge characteristics. Specifically, it was demonstrated that e-beam implantation of charges in charge-retaining plastics, such as PMMA (polymethyl methacrylate), provides a useful reference for the purpose of calibrating charge measurement instruments.<>
{"title":"Calibration of volume charge measurements by use of electron beam implantation","authors":"C. Cooke, K. Wright, N. Takasu, J. Bernstein, E. Gollin","doi":"10.1109/CEIDP.1989.69585","DOIUrl":"https://doi.org/10.1109/CEIDP.1989.69585","url":null,"abstract":"The authors consider the use of charges implanted by means of energetic electron beams to create known charge distributions for calibration purposes. For a successful calibration the reference charge samples should provide a well-defined charge, including location, distribution, and magnitude (and sign). Although these parts of the calibration may be accomplished with different samples, it is preferable for simplicity and accuracy to include these in a single sample. The e-beam implanted charge distributions have been found to achieve the needed reference charge characteristics. Specifically, it was demonstrated that e-beam implantation of charges in charge-retaining plastics, such as PMMA (polymethyl methacrylate), provides a useful reference for the purpose of calibrating charge measurement instruments.<<ETX>>","PeriodicalId":10719,"journal":{"name":"Conference on Electrical Insulation and Dielectric Phenomena,","volume":"28 1","pages":"435-441"},"PeriodicalIF":0.0,"publicationDate":"1989-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76233179","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 : 1989-10-29DOI: 10.1109/CEIDP.1989.69583
T. Furukawa, Y. Tajitu, G. E. Johnson, E. Anderson
The dielectric strength Delta epsilon and the relaxation time tau in copolymers of vinylidene fluoride (VDF) are evaluated in terms of a dipolar two-site model in the ferro, para, and melt regimes. It is shown that the two-site model can be applied to the experimental data to give a good qualitative understanding of the relaxation behavior of the copolymers of VDF. As an example, Delta epsilon and tau of BDF/TrFE (trifluoroethylene) (65/35) are shown as a function of temperature on heating and subsequent cooling at 0.5 degrees C/min. The temperature-dependent remnant polarization which fits the ferro-para transition on heating is also shown.<>
{"title":"Use of high frequency dielectric spectroscopy to investigate ferroelectric and melting transitions in copolymers of vinylidene fluoride","authors":"T. Furukawa, Y. Tajitu, G. E. Johnson, E. Anderson","doi":"10.1109/CEIDP.1989.69583","DOIUrl":"https://doi.org/10.1109/CEIDP.1989.69583","url":null,"abstract":"The dielectric strength Delta epsilon and the relaxation time tau in copolymers of vinylidene fluoride (VDF) are evaluated in terms of a dipolar two-site model in the ferro, para, and melt regimes. It is shown that the two-site model can be applied to the experimental data to give a good qualitative understanding of the relaxation behavior of the copolymers of VDF. As an example, Delta epsilon and tau of BDF/TrFE (trifluoroethylene) (65/35) are shown as a function of temperature on heating and subsequent cooling at 0.5 degrees C/min. The temperature-dependent remnant polarization which fits the ferro-para transition on heating is also shown.<<ETX>>","PeriodicalId":10719,"journal":{"name":"Conference on Electrical Insulation and Dielectric Phenomena,","volume":"34 1","pages":"422-428"},"PeriodicalIF":0.0,"publicationDate":"1989-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78422708","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 : 1989-10-29DOI: 10.1109/CEIDP.1989.69595
J. Suthar, J. Laghari
Teflon perfluoroalkoxy (PFA) film was characterized electrically to explore the possibility of its use for high-temperature high-voltage capacitors for space applications. The properties measured at temperatures up to 250 degrees C included the AC breakdown voltage and the dielectric constant and dissipation factor at frequencies up to 100 kHz. To understand the breakdown mechanism taking place at these higher temperatures, the prebreakdown conduction currents were also monitored. The results show a drastic reduction in the dielectric strength, as well as an increase in dissipation factor and conduction current with increasing temperature. The results are explained in light of the breakdown models available.<>
{"title":"High temperature studies of perfluoroalkoxy (PFA) film (for HV capacitors)","authors":"J. Suthar, J. Laghari","doi":"10.1109/CEIDP.1989.69595","DOIUrl":"https://doi.org/10.1109/CEIDP.1989.69595","url":null,"abstract":"Teflon perfluoroalkoxy (PFA) film was characterized electrically to explore the possibility of its use for high-temperature high-voltage capacitors for space applications. The properties measured at temperatures up to 250 degrees C included the AC breakdown voltage and the dielectric constant and dissipation factor at frequencies up to 100 kHz. To understand the breakdown mechanism taking place at these higher temperatures, the prebreakdown conduction currents were also monitored. The results show a drastic reduction in the dielectric strength, as well as an increase in dissipation factor and conduction current with increasing temperature. The results are explained in light of the breakdown models available.<<ETX>>","PeriodicalId":10719,"journal":{"name":"Conference on Electrical Insulation and Dielectric Phenomena,","volume":"90 1","pages":"495-502"},"PeriodicalIF":0.0,"publicationDate":"1989-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72872015","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 : 1989-10-29DOI: 10.1109/CEIDP.1989.69578
C. Ling, Liu Guiyun
The curing process of the mica-containing epoxy resin-TOA (tung oil anhydride) system was measured with a dielectric spectrometer at increasing temperatures. The theoretical analysis of the results of this dielectric spectroscopy and their experimental verification are presented. By processing the data of the tan delta versus T graph, the functional relation between the characteristic values T/sub b/, T/sub m/ of the spectroscopy and the curing reaction dynamic parameters E, k, t is established. By choosing a suitable frequency, the peak time on the tan delta -T spectroscopy is made equal to the gel time. It is concluded that this dielectric analysis at increasing temperatures makes it not only possible to study the curing characteristics of the curing reaction system but also to monitor and control the production of the stator windings of motors.<>
{"title":"Research for curing process of mica-containing epoxy resin-TOA system with dynamic dielectric spectroscopy","authors":"C. Ling, Liu Guiyun","doi":"10.1109/CEIDP.1989.69578","DOIUrl":"https://doi.org/10.1109/CEIDP.1989.69578","url":null,"abstract":"The curing process of the mica-containing epoxy resin-TOA (tung oil anhydride) system was measured with a dielectric spectrometer at increasing temperatures. The theoretical analysis of the results of this dielectric spectroscopy and their experimental verification are presented. By processing the data of the tan delta versus T graph, the functional relation between the characteristic values T/sub b/, T/sub m/ of the spectroscopy and the curing reaction dynamic parameters E, k, t is established. By choosing a suitable frequency, the peak time on the tan delta -T spectroscopy is made equal to the gel time. It is concluded that this dielectric analysis at increasing temperatures makes it not only possible to study the curing characteristics of the curing reaction system but also to monitor and control the production of the stator windings of motors.<<ETX>>","PeriodicalId":10719,"journal":{"name":"Conference on Electrical Insulation and Dielectric Phenomena,","volume":"1 1","pages":"392-397"},"PeriodicalIF":0.0,"publicationDate":"1989-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88675555","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 : 1989-10-29DOI: 10.1109/CEIDP.1989.69587
J. Chan, E.T. Cometa
The authors evaluated the impulse breakdown characteristics of several commercially available insulating liquids under a highly divergent field for the purpose of characterizing and screening potential candidate insulating liquids for use in high-voltage cables. The ASTM D-3300 needle-to-sphere impulse test was used as the basis for the evaluation. In addition, it was hoped that the impulse data on the oils could be correlated with those of the corresponding oil-paper composites, thus providing an effective tool for predicting cable performance in actual service conditions. The needle-to-sphere impulse breakdown appears to show some dependence on differences in oil composition. The needle-to-sphere impulse breakdown voltage shows a significant dependence on oil viscosity and temperature.<>
{"title":"Impulse breakdown characteristics of insulating oils and their behaviour in oil-paper composites","authors":"J. Chan, E.T. Cometa","doi":"10.1109/CEIDP.1989.69587","DOIUrl":"https://doi.org/10.1109/CEIDP.1989.69587","url":null,"abstract":"The authors evaluated the impulse breakdown characteristics of several commercially available insulating liquids under a highly divergent field for the purpose of characterizing and screening potential candidate insulating liquids for use in high-voltage cables. The ASTM D-3300 needle-to-sphere impulse test was used as the basis for the evaluation. In addition, it was hoped that the impulse data on the oils could be correlated with those of the corresponding oil-paper composites, thus providing an effective tool for predicting cable performance in actual service conditions. The needle-to-sphere impulse breakdown appears to show some dependence on differences in oil composition. The needle-to-sphere impulse breakdown voltage shows a significant dependence on oil viscosity and temperature.<<ETX>>","PeriodicalId":10719,"journal":{"name":"Conference on Electrical Insulation and Dielectric Phenomena,","volume":"16 1","pages":"447-452"},"PeriodicalIF":0.0,"publicationDate":"1989-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88030292","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 : 1989-10-29DOI: 10.1109/CEIDP.1989.69538
S. Kim, E. Cherney, R. Hackam
The results of a study on the electrical performance of room-temperature vulcanizing (RTV) silicone rubber insulator coatings under accelerated aging in a salt-fog chamber are reported. The coatings are evaluated at a severe salt-fog condition and various electric stress levels. The temporary loss and recovery of hydrophobicity are studied. Fiberglass-reinforced plastic and ethylene propylene diene monomer rubber were tested for comparison with RTV. The gradual loss of hydrophobicity as measured by leakage current and contact angle measurements is shown to be related to the physical changes in the coating brought about by dry-band arcing.<>
{"title":"The electrical performance of silicone rubber insulating coatings in a salt-fog chamber","authors":"S. Kim, E. Cherney, R. Hackam","doi":"10.1109/CEIDP.1989.69538","DOIUrl":"https://doi.org/10.1109/CEIDP.1989.69538","url":null,"abstract":"The results of a study on the electrical performance of room-temperature vulcanizing (RTV) silicone rubber insulator coatings under accelerated aging in a salt-fog chamber are reported. The coatings are evaluated at a severe salt-fog condition and various electric stress levels. The temporary loss and recovery of hydrophobicity are studied. Fiberglass-reinforced plastic and ethylene propylene diene monomer rubber were tested for comparison with RTV. The gradual loss of hydrophobicity as measured by leakage current and contact angle measurements is shown to be related to the physical changes in the coating brought about by dry-band arcing.<<ETX>>","PeriodicalId":10719,"journal":{"name":"Conference on Electrical Insulation and Dielectric Phenomena,","volume":"41 1","pages":"149-154"},"PeriodicalIF":0.0,"publicationDate":"1989-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81844639","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 : 1989-10-29DOI: 10.1109/CEIDP.1989.69584
A. Kanematsu, M. Zahn
Kerr electrooptic field mapping measurements were made in liquid nitrogen at 70 psi and -177 degrees C. A sensitive measurement technique was used whereby a small-signal AC voltage was superimposed on a DC level. The nonlinear optical effect then gave an optical signal with a DC level and AC harmonic at the same frequency as the AC voltage. The amplitude of the AC optical signal was proportional to the local electric field and was measured with a lock-in amplifier. For 6330-nm-wavelength light the Kerr constant was measured to be B approximately=10/sup -16/ m/V/sup 2/. Steady-state electric fields between parallel stainless steel electrodes of gap 7 mm and area 31.6 cm/sup 2/ were shown to be essentially uniform for field strengths up to 90 kV/cm with no significant space charge distortion. The DC voltage-current characteristic was also measured and found to be nonohmic, reaching constant current of approximately=13 nA over the voltage range of approximately=30-60 kV.<>
{"title":"Kerr electro-optic field mapping measurements in liquid nitrogen","authors":"A. Kanematsu, M. Zahn","doi":"10.1109/CEIDP.1989.69584","DOIUrl":"https://doi.org/10.1109/CEIDP.1989.69584","url":null,"abstract":"Kerr electrooptic field mapping measurements were made in liquid nitrogen at 70 psi and -177 degrees C. A sensitive measurement technique was used whereby a small-signal AC voltage was superimposed on a DC level. The nonlinear optical effect then gave an optical signal with a DC level and AC harmonic at the same frequency as the AC voltage. The amplitude of the AC optical signal was proportional to the local electric field and was measured with a lock-in amplifier. For 6330-nm-wavelength light the Kerr constant was measured to be B approximately=10/sup -16/ m/V/sup 2/. Steady-state electric fields between parallel stainless steel electrodes of gap 7 mm and area 31.6 cm/sup 2/ were shown to be essentially uniform for field strengths up to 90 kV/cm with no significant space charge distortion. The DC voltage-current characteristic was also measured and found to be nonohmic, reaching constant current of approximately=13 nA over the voltage range of approximately=30-60 kV.<<ETX>>","PeriodicalId":10719,"journal":{"name":"Conference on Electrical Insulation and Dielectric Phenomena,","volume":"74 1","pages":"429-434"},"PeriodicalIF":0.0,"publicationDate":"1989-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79860368","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 : 1989-10-29DOI: 10.1109/CEIDP.1989.69539
R. Gorur, L. A. Johnson, H.C. Hervig
In order to ensure that the silicone rubber used for cable terminations will not track or erode due to dry-band arcing, inorganic fillers, such as alumina trihydrate or silica, are usually added to the polymer. However, in order to satisfy the easy installation requirement, the filler concentration is usually lower than that used for outdoor polymer insulators. The reduced filler loadings have caused premature failures in certain laboratory tests, but the same terminations have been successfully used in the field for over 20 years. In order to determine the factors of this discrepancy, a systematic evaluation in a fog chamber was performed, where the experimental conditions were varied over a wide range. Changes occurring in the polymer were monitored periodically using electron spectroscopy for chemical analysis. It is demonstrated that the experimental conditions play a significant role in the accelerated aging of silicone rubber terminations. Good correlation with experience in the field is obtained when the test parameters allow the material to recover its hydrophobicity.<>
{"title":"Accelerated aging of silicone rubber cable terminations","authors":"R. Gorur, L. A. Johnson, H.C. Hervig","doi":"10.1109/CEIDP.1989.69539","DOIUrl":"https://doi.org/10.1109/CEIDP.1989.69539","url":null,"abstract":"In order to ensure that the silicone rubber used for cable terminations will not track or erode due to dry-band arcing, inorganic fillers, such as alumina trihydrate or silica, are usually added to the polymer. However, in order to satisfy the easy installation requirement, the filler concentration is usually lower than that used for outdoor polymer insulators. The reduced filler loadings have caused premature failures in certain laboratory tests, but the same terminations have been successfully used in the field for over 20 years. In order to determine the factors of this discrepancy, a systematic evaluation in a fog chamber was performed, where the experimental conditions were varied over a wide range. Changes occurring in the polymer were monitored periodically using electron spectroscopy for chemical analysis. It is demonstrated that the experimental conditions play a significant role in the accelerated aging of silicone rubber terminations. Good correlation with experience in the field is obtained when the test parameters allow the material to recover its hydrophobicity.<<ETX>>","PeriodicalId":10719,"journal":{"name":"Conference on Electrical Insulation and Dielectric Phenomena,","volume":"83 1","pages":"155-160"},"PeriodicalIF":0.0,"publicationDate":"1989-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88906986","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 : 1989-10-29DOI: 10.1109/CEIDP.1989.69577
Liu Yaonan, Cao Xiaolong
The existence of a liquid-liquid transition in atactic polymethyl methacrylate (PMMA) is confirmed by means of dielectric spectroscopy and DSC (differential scanning calorimetry) thermal analysis. From the point of view of thermodynamics, the appearance of the maximum value of the epsilon '-T curve at a temperature approaching the transition point is illustrated. The results of dielectric temperature dependence at low frequency and DSC thermal analysis demonstrate that for atactic PMMA there is a structural transition near 170 degrees C. The ordered structure is regionally distributed. The permittivity and/or conductivity are different in different regions, so that interfacial polarization occurs.<>
{"title":"The study of liquid-liquid transition of atactic polymethylmethacrylate by dielectric spectroscopy","authors":"Liu Yaonan, Cao Xiaolong","doi":"10.1109/CEIDP.1989.69577","DOIUrl":"https://doi.org/10.1109/CEIDP.1989.69577","url":null,"abstract":"The existence of a liquid-liquid transition in atactic polymethyl methacrylate (PMMA) is confirmed by means of dielectric spectroscopy and DSC (differential scanning calorimetry) thermal analysis. From the point of view of thermodynamics, the appearance of the maximum value of the epsilon '-T curve at a temperature approaching the transition point is illustrated. The results of dielectric temperature dependence at low frequency and DSC thermal analysis demonstrate that for atactic PMMA there is a structural transition near 170 degrees C. The ordered structure is regionally distributed. The permittivity and/or conductivity are different in different regions, so that interfacial polarization occurs.<<ETX>>","PeriodicalId":10719,"journal":{"name":"Conference on Electrical Insulation and Dielectric Phenomena,","volume":"89 1","pages":"386-391"},"PeriodicalIF":0.0,"publicationDate":"1989-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76263136","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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