Pub Date : 1993-10-17DOI: 10.1109/CEIDP.1993.378984
M.-S.E. Wang, M. Campos, E. Forster
Five current peaks were observed in the thermally stimulated current (TSC) spectra of poly(p-phenylene sulfide) (PPS) films over the temperature range of 25 to 250/spl deg/C. At a heating rate of 2/spl deg/C/min, these peaks appeared at 43.5, 92, 121, 163, and 193/spl deg/C, respectively. Based on differential scanning calorimetry and literature data, the a peak at 43.5/spl deg/C and the b peak at 92/spl deg/C were attributed to the dielectric manifestation of sub-T/sub g/ and T/sub g/ transitions, respectively. The c peak at 121/spl deg/C was demonstrated to be caused by the crystallization of the amorphous part during the heating run. The d peak at 163/spl deg/C was likely associated with the slight crosslinking and/or chain extension of the polymers during the sample preparation. The e peak at 193/spl deg/C was attributed to the release of injected space charges trapped at the amorphous-crystal interfaces. A two-step molding method which greatly improved the PPS films' preparation was also developed.<>
{"title":"Characterization of poly(p-phenylene sulfide) polymers by thermally stimulated charging/discharging currents measurements","authors":"M.-S.E. Wang, M. Campos, E. Forster","doi":"10.1109/CEIDP.1993.378984","DOIUrl":"https://doi.org/10.1109/CEIDP.1993.378984","url":null,"abstract":"Five current peaks were observed in the thermally stimulated current (TSC) spectra of poly(p-phenylene sulfide) (PPS) films over the temperature range of 25 to 250/spl deg/C. At a heating rate of 2/spl deg/C/min, these peaks appeared at 43.5, 92, 121, 163, and 193/spl deg/C, respectively. Based on differential scanning calorimetry and literature data, the a peak at 43.5/spl deg/C and the b peak at 92/spl deg/C were attributed to the dielectric manifestation of sub-T/sub g/ and T/sub g/ transitions, respectively. The c peak at 121/spl deg/C was demonstrated to be caused by the crystallization of the amorphous part during the heating run. The d peak at 163/spl deg/C was likely associated with the slight crosslinking and/or chain extension of the polymers during the sample preparation. The e peak at 193/spl deg/C was attributed to the release of injected space charges trapped at the amorphous-crystal interfaces. A two-step molding method which greatly improved the PPS films' preparation was also developed.<<ETX>>","PeriodicalId":149803,"journal":{"name":"Proceedings of IEEE Conference on Electrical Insulation and Dielectric Phenomena - (CEIDP '93)","volume":"72 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125243814","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 : 1993-10-17DOI: 10.1109/CEIDP.1993.378884
P. Tharning, P. Werelius, B. Holmgren, U. Gafvert
The authors report on a high-voltage, frequency-domain measurement system capable of resolving losses in unaged XLPE (cross-linked polyethylene). The system allows analyses of harmonics as well as of the fundamental frequency. The highest operating voltage is 20 kV and the frequency range is 0.0001 Hz to 1000 Hz. Different XLPE cable samples (new, artificially aged, field aged) were measured in the frequency domain using 4 kV peak voltage at a temperature of 22/spl deg/C.<>
{"title":"High voltage dielectric response analyser for cable diagnostics","authors":"P. Tharning, P. Werelius, B. Holmgren, U. Gafvert","doi":"10.1109/CEIDP.1993.378884","DOIUrl":"https://doi.org/10.1109/CEIDP.1993.378884","url":null,"abstract":"The authors report on a high-voltage, frequency-domain measurement system capable of resolving losses in unaged XLPE (cross-linked polyethylene). The system allows analyses of harmonics as well as of the fundamental frequency. The highest operating voltage is 20 kV and the frequency range is 0.0001 Hz to 1000 Hz. Different XLPE cable samples (new, artificially aged, field aged) were measured in the frequency domain using 4 kV peak voltage at a temperature of 22/spl deg/C.<<ETX>>","PeriodicalId":149803,"journal":{"name":"Proceedings of IEEE Conference on Electrical Insulation and Dielectric Phenomena - (CEIDP '93)","volume":"2010 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131467997","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 : 1993-10-17DOI: 10.1109/CEIDP.1993.378920
A. Al-Attabi, R. Fouracre, H. M. Banford, H. Li
Measurements of /spl epsi/" as a function of frequency and temperature have been undertaken in a preliminary investigation of the effects of neutron radiation on samples of an epoxy resin. Samples were produced from a diglycidel ether of bisphenol A resin. Transient discharging currents were also measured, and attempts were made to analyze the data using either the Hamon approximation or a Fourier transform technique. The preliminary data indicate that the DC transient is not governed by a t/sup -n/ dependence. Fourier analysis of these data to obtain low-frequency dielectric information indicates the presence of a loss peak. The increase of /spl epsi/" at lower frequencies observed in the loss analyzer data might be attributable to DC conductivity effects.<>
{"title":"An investigation of low frequency dielectric response to monitor radiation induced changes in epoxy resin samples","authors":"A. Al-Attabi, R. Fouracre, H. M. Banford, H. Li","doi":"10.1109/CEIDP.1993.378920","DOIUrl":"https://doi.org/10.1109/CEIDP.1993.378920","url":null,"abstract":"Measurements of /spl epsi/\" as a function of frequency and temperature have been undertaken in a preliminary investigation of the effects of neutron radiation on samples of an epoxy resin. Samples were produced from a diglycidel ether of bisphenol A resin. Transient discharging currents were also measured, and attempts were made to analyze the data using either the Hamon approximation or a Fourier transform technique. The preliminary data indicate that the DC transient is not governed by a t/sup -n/ dependence. Fourier analysis of these data to obtain low-frequency dielectric information indicates the presence of a loss peak. The increase of /spl epsi/\" at lower frequencies observed in the loss analyzer data might be attributable to DC conductivity effects.<<ETX>>","PeriodicalId":149803,"journal":{"name":"Proceedings of IEEE Conference on Electrical Insulation and Dielectric Phenomena - (CEIDP '93)","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115138683","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 : 1993-10-17DOI: 10.1109/CEIDP.1993.378898
A. Svatik, P. Scarpa, D. Das-Gupta, D. Cooper, C. Rackowski
Thermally stimulated discharge current (TSDC) measurement and dielectric spectroscopy of low-density polyethylene (LDPE) aged with an AC field and liquid electrodes are reported. The dielectric response of aged sample after DC poling at 70/spl deg/C shows two parallel relaxation processes. At low frequencies an LFD (low-frequency dispersion) process with a constant /spl epsi/"//spl epsi/' ratio is dominant, possibly due to the presence of ionic species in LDPE. At higher frequencies an additional dipolelike relaxation occurs as a result of charge injection and trapping enhanced by electrical ageing. Without DC poling at high temperature only the LFD is evident. The unaged sample does not show any fundamental changes in the dielectric response after additional DC poling, thus indicating the absence of a significant trap density.<>
{"title":"Dielectric polarization and relaxation behaviour of AC aged polyethylene with liquid electrodes","authors":"A. Svatik, P. Scarpa, D. Das-Gupta, D. Cooper, C. Rackowski","doi":"10.1109/CEIDP.1993.378898","DOIUrl":"https://doi.org/10.1109/CEIDP.1993.378898","url":null,"abstract":"Thermally stimulated discharge current (TSDC) measurement and dielectric spectroscopy of low-density polyethylene (LDPE) aged with an AC field and liquid electrodes are reported. The dielectric response of aged sample after DC poling at 70/spl deg/C shows two parallel relaxation processes. At low frequencies an LFD (low-frequency dispersion) process with a constant /spl epsi/\"//spl epsi/' ratio is dominant, possibly due to the presence of ionic species in LDPE. At higher frequencies an additional dipolelike relaxation occurs as a result of charge injection and trapping enhanced by electrical ageing. Without DC poling at high temperature only the LFD is evident. The unaged sample does not show any fundamental changes in the dielectric response after additional DC poling, thus indicating the absence of a significant trap density.<<ETX>>","PeriodicalId":149803,"journal":{"name":"Proceedings of IEEE Conference on Electrical Insulation and Dielectric Phenomena - (CEIDP '93)","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131992634","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 : 1993-10-17DOI: 10.1109/CEIDP.1993.378960
J. Giacometti, A. Dereggi, G. T. Davis, B. Dickens
The thermal pulse technique was used to measure the electric polarization and its distribution in the alternating copolymer of vinylidene cyanide and vinyl acetate P (VDCN-VAc), with poling voltage and poling temperature as variables. The thermal stability of the polarization was evaluated at several ageing temperatures up to the glass transition temperature. The polarization was found to be proportional to the poling field up to 50 MV/m and very stable for ageing temperatures up to 150/spl deg/C.<>
{"title":"Thermal pulse study of the electric polarization in P(VDCN-VAc)","authors":"J. Giacometti, A. Dereggi, G. T. Davis, B. Dickens","doi":"10.1109/CEIDP.1993.378960","DOIUrl":"https://doi.org/10.1109/CEIDP.1993.378960","url":null,"abstract":"The thermal pulse technique was used to measure the electric polarization and its distribution in the alternating copolymer of vinylidene cyanide and vinyl acetate P (VDCN-VAc), with poling voltage and poling temperature as variables. The thermal stability of the polarization was evaluated at several ageing temperatures up to the glass transition temperature. The polarization was found to be proportional to the poling field up to 50 MV/m and very stable for ageing temperatures up to 150/spl deg/C.<<ETX>>","PeriodicalId":149803,"journal":{"name":"Proceedings of IEEE Conference on Electrical Insulation and Dielectric Phenomena - (CEIDP '93)","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115469790","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 : 1993-10-17DOI: 10.1109/CEIDP.1993.378994
P.A. Washabaugh, M. Zahn
In the nonaqueous weakly ionized hydrocarbon solutions where flow electrification has been a hazard, the charge transfer processes are not well understood because the ionic species are typically present in trace amounts and their chemical composition is unknown. As a result, postulated boundary conditions have been used, such as a constant zeta potential or wall charge density, a constant gradient in the volume charge density, or a wall current density that is proportional to the difference between the volume charge density and an equilibrium value. The applicability of these boundary conditions is explored. Measurements of the electrification volume charge density between rotating cylindrical stainless steel electrodes, with transformer oil filling the annulus between the cylinders, showed the steady-state charge density increasing linearly with low applied DC voltages (with fields of order 10/sup 3/V/m). Transient measurements, with the inner cylinder covered by pressboard insulation, when the DC voltage is alternately connected and disconnected, suggest that the interfacial surface charge and electric field affect the electrification volume charge density.<>
{"title":"Application of DC voltages for determining flow electrification boundary conditions","authors":"P.A. Washabaugh, M. Zahn","doi":"10.1109/CEIDP.1993.378994","DOIUrl":"https://doi.org/10.1109/CEIDP.1993.378994","url":null,"abstract":"In the nonaqueous weakly ionized hydrocarbon solutions where flow electrification has been a hazard, the charge transfer processes are not well understood because the ionic species are typically present in trace amounts and their chemical composition is unknown. As a result, postulated boundary conditions have been used, such as a constant zeta potential or wall charge density, a constant gradient in the volume charge density, or a wall current density that is proportional to the difference between the volume charge density and an equilibrium value. The applicability of these boundary conditions is explored. Measurements of the electrification volume charge density between rotating cylindrical stainless steel electrodes, with transformer oil filling the annulus between the cylinders, showed the steady-state charge density increasing linearly with low applied DC voltages (with fields of order 10/sup 3/V/m). Transient measurements, with the inner cylinder covered by pressboard insulation, when the DC voltage is alternately connected and disconnected, suggest that the interfacial surface charge and electric field affect the electrification volume charge density.<<ETX>>","PeriodicalId":149803,"journal":{"name":"Proceedings of IEEE Conference on Electrical Insulation and Dielectric Phenomena - (CEIDP '93)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129266152","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 : 1993-10-17DOI: 10.1109/CEIDP.1993.378913
K. Mallikarjunappa, C. Viswanatha, S.N. Moorching
Multifactor accelerated ageing studied have been carried out on scaled-down model coils of an 11-kV insulation system. The test parameters tan delta tip-up (/spl delta/T), capacitance tip-up (/spl Delta/C/C), integrated discharge energy (IDE), and discharge inception voltage (Vi) were monitored at regular intervals during the ageing period to characterize the ageing processes. Attempts have been made to find the correlation between different test parameters as a function of ageing time. A good correlation is found to exist between /spl delta/T and /spl delta/C/C. The degree of correlation between different test parameters tends to increase as the ageing proceeds.<>
{"title":"Multi-factor ageing of stator coil insulation of HV machines and degree of correlation among non-destructive test parameters","authors":"K. Mallikarjunappa, C. Viswanatha, S.N. Moorching","doi":"10.1109/CEIDP.1993.378913","DOIUrl":"https://doi.org/10.1109/CEIDP.1993.378913","url":null,"abstract":"Multifactor accelerated ageing studied have been carried out on scaled-down model coils of an 11-kV insulation system. The test parameters tan delta tip-up (/spl delta/T), capacitance tip-up (/spl Delta/C/C), integrated discharge energy (IDE), and discharge inception voltage (Vi) were monitored at regular intervals during the ageing period to characterize the ageing processes. Attempts have been made to find the correlation between different test parameters as a function of ageing time. A good correlation is found to exist between /spl delta/T and /spl delta/C/C. The degree of correlation between different test parameters tends to increase as the ageing proceeds.<<ETX>>","PeriodicalId":149803,"journal":{"name":"Proceedings of IEEE Conference on Electrical Insulation and Dielectric Phenomena - (CEIDP '93)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129751920","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 : 1993-10-17DOI: 10.1109/CEIDP.1993.378941
J.P. Zheng, P. Cygan, T. Jow
The breakdown strength of polymer laminates, polymer base films coated with thin layers of polyvinylidene fluoride (PVDF), was investigated. The PVDF film was coated using a spin coating technique. The DC breakdown strength was studied using an ASTM standard and could be increased by as much as 20% for the polyetherimide laminates. It was found that this breakdown strength was insensitive to the thickness of the polymer base films and the PVDF films. Other dielectric properties such as the dielectric constant dissipation factor were also studied for the samples with and without PVDF coatings. Possible mechanisms for the enhancement of breakdown strength are discussed.<>
{"title":"Enhancement of breakdown strength of polyetherimide laminates","authors":"J.P. Zheng, P. Cygan, T. Jow","doi":"10.1109/CEIDP.1993.378941","DOIUrl":"https://doi.org/10.1109/CEIDP.1993.378941","url":null,"abstract":"The breakdown strength of polymer laminates, polymer base films coated with thin layers of polyvinylidene fluoride (PVDF), was investigated. The PVDF film was coated using a spin coating technique. The DC breakdown strength was studied using an ASTM standard and could be increased by as much as 20% for the polyetherimide laminates. It was found that this breakdown strength was insensitive to the thickness of the polymer base films and the PVDF films. Other dielectric properties such as the dielectric constant dissipation factor were also studied for the samples with and without PVDF coatings. Possible mechanisms for the enhancement of breakdown strength are discussed.<<ETX>>","PeriodicalId":149803,"journal":{"name":"Proceedings of IEEE Conference on Electrical Insulation and Dielectric Phenomena - (CEIDP '93)","volume":"113 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125914120","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 : 1993-10-17DOI: 10.1109/CEIDP.1993.378909
T. Nishi, R. Hanaoka, R. Ishibashi, T. Kohrin
A thin groove was installed on the surface of insulated test wire longitudinally from the free end of the binding wire. Creeping discharge was photographed with the aid of an image intensifier. The effect of this groove on the progression of the leader stroke under dry and wet conditions was investigated. Positive creeping discharges are shown to progress with jumps across the surface of the wire. Negative ones progress while in contact with the surface. Under dry conditions, the progression distances of negative leader strokes in the presence of a groove are longer than those without a groove. Under wet conditions without a groove, progression distances of negative leader strokes are longer than those under dry conditions.<>
{"title":"Impulse creeping discharge phenomena at insulator supporting points of aerial insulated wires","authors":"T. Nishi, R. Hanaoka, R. Ishibashi, T. Kohrin","doi":"10.1109/CEIDP.1993.378909","DOIUrl":"https://doi.org/10.1109/CEIDP.1993.378909","url":null,"abstract":"A thin groove was installed on the surface of insulated test wire longitudinally from the free end of the binding wire. Creeping discharge was photographed with the aid of an image intensifier. The effect of this groove on the progression of the leader stroke under dry and wet conditions was investigated. Positive creeping discharges are shown to progress with jumps across the surface of the wire. Negative ones progress while in contact with the surface. Under dry conditions, the progression distances of negative leader strokes in the presence of a groove are longer than those without a groove. Under wet conditions without a groove, progression distances of negative leader strokes are longer than those under dry conditions.<<ETX>>","PeriodicalId":149803,"journal":{"name":"Proceedings of IEEE Conference on Electrical Insulation and Dielectric Phenomena - (CEIDP '93)","volume":"112 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127528901","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 : 1993-10-17DOI: 10.1109/CEIDP.1993.378964
S. Matsuoka, G. Johnson, X. Quan
The conformational relaxation near the glass transition is a local intermolecular cooperativity phenomenon. As the temperature is lowered, the domains of cooperativity grow in size toward the infinite size but never reach it. The relaxation function is derived from the distribution of domain size according to the equipartition principle. It fits data better than the KWW equation, particularly at high frequencies. This distribution implies that a significant number of conformers continue to undergo liquid-like (picosecond) relaxation even near the glass transition temperature.<>
{"title":"Cooperative relaxation processes in glass forming polymers and non-polymers","authors":"S. Matsuoka, G. Johnson, X. Quan","doi":"10.1109/CEIDP.1993.378964","DOIUrl":"https://doi.org/10.1109/CEIDP.1993.378964","url":null,"abstract":"The conformational relaxation near the glass transition is a local intermolecular cooperativity phenomenon. As the temperature is lowered, the domains of cooperativity grow in size toward the infinite size but never reach it. The relaxation function is derived from the distribution of domain size according to the equipartition principle. It fits data better than the KWW equation, particularly at high frequencies. This distribution implies that a significant number of conformers continue to undergo liquid-like (picosecond) relaxation even near the glass transition temperature.<<ETX>>","PeriodicalId":149803,"journal":{"name":"Proceedings of IEEE Conference on Electrical Insulation and Dielectric Phenomena - (CEIDP '93)","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1993-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116666665","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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