Pub Date : 1994-07-03DOI: 10.1109/ICPADM.1994.413931
K. Tohyama, T. Tokoro, M. Nagao, M. Kosaki
To study the high-field AC conduction mechanisms of nonpolar polymers, the AC dissipation current waveforms are observed. The shapes of the AC dissipation current waveforms in the high-held and high-temperature region become the triangle shape in spite of the sinusoidal voltage application, suggesting the nonlinear electric field dependence of instantaneous AC conductivity. The fast rising AC ramp voltage application method is developed as the new technique to examine the dielectric properties in the very short time range. This method enables the measurement of the variations of the high-field dielectric properties and the dissipation current waveform immediately after the voltage application. The new measurements were carried out on electron beam (EB) irradiated crosslinked polyethylene (IR-XLPE) film. The dissipation current waveforms in the high temperature region show the peak in the former part of each half cycle and quickly decrease in the latter part of each half cycle of a full waveform, which seems to show that the carrier injection from the electrode is assisted by the heterospace charge in the region near the electrode.<>
{"title":"Variations of high-field dissipation current waveform under AC ramp voltage application","authors":"K. Tohyama, T. Tokoro, M. Nagao, M. Kosaki","doi":"10.1109/ICPADM.1994.413931","DOIUrl":"https://doi.org/10.1109/ICPADM.1994.413931","url":null,"abstract":"To study the high-field AC conduction mechanisms of nonpolar polymers, the AC dissipation current waveforms are observed. The shapes of the AC dissipation current waveforms in the high-held and high-temperature region become the triangle shape in spite of the sinusoidal voltage application, suggesting the nonlinear electric field dependence of instantaneous AC conductivity. The fast rising AC ramp voltage application method is developed as the new technique to examine the dielectric properties in the very short time range. This method enables the measurement of the variations of the high-field dielectric properties and the dissipation current waveform immediately after the voltage application. The new measurements were carried out on electron beam (EB) irradiated crosslinked polyethylene (IR-XLPE) film. The dissipation current waveforms in the high temperature region show the peak in the former part of each half cycle and quickly decrease in the latter part of each half cycle of a full waveform, which seems to show that the carrier injection from the electrode is assisted by the heterospace charge in the region near the electrode.<<ETX>>","PeriodicalId":331058,"journal":{"name":"Proceedings of 1994 4th International Conference on Properties and Applications of Dielectric Materials (ICPADM)","volume":"25 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":"133811426","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.1994.413952
H. Chae, Y. Shin, K.J. Lim, H. Bae, D. Shin
When piezoelectric ceramics are used in high power piezoelectric devices, such as piezoelectric actuators, ultrasonic motors etc., the piezoelectric constants of the ceramics at high vibration level are important. In this paper, lead titanate (PT)-lead zirconate (PZ)-lead cadmium niobate (PCN) piezoelectric ceramics were prepared and vibration dependence of piezoelectric constants of the ceramic are investigated. The resonant and anti-resonant frequencies, mechanical quality factor, and other piezoelectric constants were measured as a function of vibration velocity.<>
{"title":"Vibration level dependence of piezoelectric constant in PT-PZ-PCN system ceramic","authors":"H. Chae, Y. Shin, K.J. Lim, H. Bae, D. Shin","doi":"10.1109/ICPADM.1994.413952","DOIUrl":"https://doi.org/10.1109/ICPADM.1994.413952","url":null,"abstract":"When piezoelectric ceramics are used in high power piezoelectric devices, such as piezoelectric actuators, ultrasonic motors etc., the piezoelectric constants of the ceramics at high vibration level are important. In this paper, lead titanate (PT)-lead zirconate (PZ)-lead cadmium niobate (PCN) piezoelectric ceramics were prepared and vibration dependence of piezoelectric constants of the ceramic are investigated. The resonant and anti-resonant frequencies, mechanical quality factor, and other piezoelectric constants were measured as a function of vibration velocity.<<ETX>>","PeriodicalId":331058,"journal":{"name":"Proceedings of 1994 4th International Conference on Properties and Applications of Dielectric Materials (ICPADM)","volume":"200 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":"133903385","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.1994.414000
T. Imakoma, Y. Suzuki, O. Fujii, I. Nakajima
A degradation of silicone rubber for polymer insulator housing by ultraviolet radiation was studied. The following techniques were used to investigate surface degradation of silicone rubber: Measurement of Contact Angle; Energy Dispersive X-ray (EDX) Analysis; Fourier Transform Infra-Red (FT-IR) Spectroscopy; Scanning Electron Microscope (SEM) Observation. It was found from the investigation that chemical composition near the surface was changed significantly and that hydrophobicity was reduced under severe ultraviolet radiation.<>
{"title":"Degradation of silicone rubber housing by ultraviolet radiation","authors":"T. Imakoma, Y. Suzuki, O. Fujii, I. Nakajima","doi":"10.1109/ICPADM.1994.414000","DOIUrl":"https://doi.org/10.1109/ICPADM.1994.414000","url":null,"abstract":"A degradation of silicone rubber for polymer insulator housing by ultraviolet radiation was studied. The following techniques were used to investigate surface degradation of silicone rubber: Measurement of Contact Angle; Energy Dispersive X-ray (EDX) Analysis; Fourier Transform Infra-Red (FT-IR) Spectroscopy; Scanning Electron Microscope (SEM) Observation. It was found from the investigation that chemical composition near the surface was changed significantly and that hydrophobicity was reduced under severe ultraviolet radiation.<<ETX>>","PeriodicalId":331058,"journal":{"name":"Proceedings of 1994 4th International Conference on Properties and Applications of Dielectric Materials (ICPADM)","volume":"67 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":"133132118","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.1994.413914
M. Pompili, A. Mundula, C. Mazzetti, C. Puliti
Recent study of the electric properties of perfluoro polyethers (PFPE) have shown that these molecules may be useful as insulating fluids in power transformers and capacitors. To assure their environmental compatibility, a study has been performed of the products formed in the course of electrical discharges of controlled energy. This study includes an analysis of the gaseous products formed. In this paper the first obtained results of gas chromatography and mass spectra analysis of the decomposition compounds produced after several breakdowns in PFPE are presented and discussed.<>
{"title":"Environmental compatibility of perfluoro polyethers, a family of new dielectric fluids","authors":"M. Pompili, A. Mundula, C. Mazzetti, C. Puliti","doi":"10.1109/ICPADM.1994.413914","DOIUrl":"https://doi.org/10.1109/ICPADM.1994.413914","url":null,"abstract":"Recent study of the electric properties of perfluoro polyethers (PFPE) have shown that these molecules may be useful as insulating fluids in power transformers and capacitors. To assure their environmental compatibility, a study has been performed of the products formed in the course of electrical discharges of controlled energy. This study includes an analysis of the gaseous products formed. In this paper the first obtained results of gas chromatography and mass spectra analysis of the decomposition compounds produced after several breakdowns in PFPE are presented and discussed.<<ETX>>","PeriodicalId":331058,"journal":{"name":"Proceedings of 1994 4th International Conference on Properties and Applications of Dielectric Materials (ICPADM)","volume":"13 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":"132671079","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.1994.414138
Z. Yingsuo
This paper describes the new results of investigations on a rapid thermal endurance test method for insulating materials-TPS. (1) The functional exposure test in the TPS may be performed by means of the changing temperature technique. To do so may save both testing time and costs, and raise the reliability of the TPS method. Hence, it would be of important significance. (2) The equation of calculating Ep in the TPS has excellent repeatability, which is one of the main advantages of TPS, and not so called insensitivity. (3) TG tests play an auxiliary role in TPS, this is decided by the principle of the conventional aging method, and should be reasonable and beneficial to the accuracy of TPS. (4) Since there is a statistical linear relation between E and f for a category of insulating materials, as well as the verification results of many new and old materials, this has confirmed that the accuracy of the TPS as against conventional aging is satisfactory. The TPS method may be used to evaluate thermal endurance for new insulating materials.<>
{"title":"New progress of studies on thermogravimetric point slope (TPS) method","authors":"Z. Yingsuo","doi":"10.1109/ICPADM.1994.414138","DOIUrl":"https://doi.org/10.1109/ICPADM.1994.414138","url":null,"abstract":"This paper describes the new results of investigations on a rapid thermal endurance test method for insulating materials-TPS. (1) The functional exposure test in the TPS may be performed by means of the changing temperature technique. To do so may save both testing time and costs, and raise the reliability of the TPS method. Hence, it would be of important significance. (2) The equation of calculating Ep in the TPS has excellent repeatability, which is one of the main advantages of TPS, and not so called insensitivity. (3) TG tests play an auxiliary role in TPS, this is decided by the principle of the conventional aging method, and should be reasonable and beneficial to the accuracy of TPS. (4) Since there is a statistical linear relation between E and f for a category of insulating materials, as well as the verification results of many new and old materials, this has confirmed that the accuracy of the TPS as against conventional aging is satisfactory. The TPS method may be used to evaluate thermal endurance for new insulating materials.<<ETX>>","PeriodicalId":331058,"journal":{"name":"Proceedings of 1994 4th International Conference on Properties and Applications of Dielectric Materials (ICPADM)","volume":"21 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":"116330584","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.1994.414148
L. Lamarre, D. Fournier, R. Morin
Underground power distribution cable joints, which showed detectable levels of partial discharges (PD) in service, were removed and submitted to an accelerated ageing test in a laboratory. Prior to, and after ageing, the joints were examined by X-rays to check for any cavity or air gap that could be the site of PD generation. During ageing, the joints were simultaneously monitored with an infrared camera to locate any hot spot, and with a portable partial discharge detector, to locate precisely the areas of PD generation. The ageing test comprises overstressing at 3 p.u. and thermal cycling at 130/spl deg/C and lasts until joint failure. The aim is to attempt to define a critical PD threshold (as measured by the portable instrument) at which failure is imminent.<>
{"title":"Early detection of faults in underground distribution cable joints by partial discharge measurements","authors":"L. Lamarre, D. Fournier, R. Morin","doi":"10.1109/ICPADM.1994.414148","DOIUrl":"https://doi.org/10.1109/ICPADM.1994.414148","url":null,"abstract":"Underground power distribution cable joints, which showed detectable levels of partial discharges (PD) in service, were removed and submitted to an accelerated ageing test in a laboratory. Prior to, and after ageing, the joints were examined by X-rays to check for any cavity or air gap that could be the site of PD generation. During ageing, the joints were simultaneously monitored with an infrared camera to locate any hot spot, and with a portable partial discharge detector, to locate precisely the areas of PD generation. The ageing test comprises overstressing at 3 p.u. and thermal cycling at 130/spl deg/C and lasts until joint failure. The aim is to attempt to define a critical PD threshold (as measured by the portable instrument) at which failure is imminent.<<ETX>>","PeriodicalId":331058,"journal":{"name":"Proceedings of 1994 4th International Conference on Properties and Applications of Dielectric Materials (ICPADM)","volume":"34 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":"121153235","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.1994.413929
G. Montanari, A. Motori, F. Sandrolini
A model for the long-term behavior of charging current is proposed. It is based on the "universal" law of Jonscher (1983), where a threshold term, function of the steady-state current, has been introduced. On the basis of several sets of data relevant to different insulating polymeric materials, it is shown that the DC conductivity can be evaluated, in many cases, even by not too-long test times. Correct estimates of the activation energy of conduction, as well as of polarization processes, can be obtained by means of the model.<>
{"title":"A mathematical model for charging currents of polymeric insulating materials","authors":"G. Montanari, A. Motori, F. Sandrolini","doi":"10.1109/ICPADM.1994.413929","DOIUrl":"https://doi.org/10.1109/ICPADM.1994.413929","url":null,"abstract":"A model for the long-term behavior of charging current is proposed. It is based on the \"universal\" law of Jonscher (1983), where a threshold term, function of the steady-state current, has been introduced. On the basis of several sets of data relevant to different insulating polymeric materials, it is shown that the DC conductivity can be evaluated, in many cases, even by not too-long test times. Correct estimates of the activation energy of conduction, as well as of polarization processes, can be obtained by means of the model.<<ETX>>","PeriodicalId":331058,"journal":{"name":"Proceedings of 1994 4th International Conference on Properties and Applications of Dielectric Materials (ICPADM)","volume":"4 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":"121220326","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.1994.414149
P. G. Lang, D. Allan, Y. Zhou
This paper examines the possibility of remote detection of defective disc insulators on overhead transmission lines. Application of infrared thermal imaging systems is studied in relation to the very small temperature differentials between sound and faulty discs, and the many influencing factors that significantly reduce sensitivity. The application of corona detection techniques appears to present a complementary approach. The objective is to understand the mechanisms involved in order to develop more cost-effective diagnostic techniques for this class of equipment.<>
{"title":"The investigation of insulation defects in transmission line disc insulators using remote detection techniques","authors":"P. G. Lang, D. Allan, Y. Zhou","doi":"10.1109/ICPADM.1994.414149","DOIUrl":"https://doi.org/10.1109/ICPADM.1994.414149","url":null,"abstract":"This paper examines the possibility of remote detection of defective disc insulators on overhead transmission lines. Application of infrared thermal imaging systems is studied in relation to the very small temperature differentials between sound and faulty discs, and the many influencing factors that significantly reduce sensitivity. The application of corona detection techniques appears to present a complementary approach. The objective is to understand the mechanisms involved in order to develop more cost-effective diagnostic techniques for this class of equipment.<<ETX>>","PeriodicalId":331058,"journal":{"name":"Proceedings of 1994 4th International Conference on Properties and Applications of Dielectric Materials (ICPADM)","volume":"31 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":"123860881","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.1994.414037
T. Czaszejko
A laboratory experiment was performed in order to determine the influence of a short exposure to DC voltage on the growth of water trees in XLPE cable insulation. The results are of some practical importance, for a DC test voltage is commonly used by utilities when re-commissioning polymeric cable systems which have been previously energised. An accelerated water tree growth from a needle electrode was induced on the surface of samples of cable insulation. At various stages of water tree growth the DC voltage of 4U/sub 0/ (where U/sub 0/ is the rms rated voltage of the cable) was applied for duration of 15 minutes. After the DC exposure, water tree aging continued under AC conditions, and amounted to a total of 296 hours for each sample. The results have shown that there is an increase in the length of water trees grown in samples subjected to a DC voltage compared with the control sample aged, for the same period of time, without the DC exposure.<>
{"title":"Growth of water trees exposed to DC voltage","authors":"T. Czaszejko","doi":"10.1109/ICPADM.1994.414037","DOIUrl":"https://doi.org/10.1109/ICPADM.1994.414037","url":null,"abstract":"A laboratory experiment was performed in order to determine the influence of a short exposure to DC voltage on the growth of water trees in XLPE cable insulation. The results are of some practical importance, for a DC test voltage is commonly used by utilities when re-commissioning polymeric cable systems which have been previously energised. An accelerated water tree growth from a needle electrode was induced on the surface of samples of cable insulation. At various stages of water tree growth the DC voltage of 4U/sub 0/ (where U/sub 0/ is the rms rated voltage of the cable) was applied for duration of 15 minutes. After the DC exposure, water tree aging continued under AC conditions, and amounted to a total of 296 hours for each sample. The results have shown that there is an increase in the length of water trees grown in samples subjected to a DC voltage compared with the control sample aged, for the same period of time, without the DC exposure.<<ETX>>","PeriodicalId":331058,"journal":{"name":"Proceedings of 1994 4th International Conference on Properties and Applications of Dielectric Materials (ICPADM)","volume":"69 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":"124628343","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.1994.414081
L. Yao, Q. Su
Insulation degradation of high voltage equipment has been one of the major concerns of electricity supply authorities. Amongst the many indicators that can be used to assess the insulation condition of high voltage equipment, partial discharge testing has been one of the most effective diagnostic tools for monitoring the condition of electrical insulation. A new detector has been developed for the measurement of partial discharges in high voltage equipment using radio transmission techniques. Experiments carried out in the laboratory have shown that the new detector has many advantages over the conventional PD detectors. It is believed that this is initial in the PD detection area in the world.<>
{"title":"A new partial discharge detector","authors":"L. Yao, Q. Su","doi":"10.1109/ICPADM.1994.414081","DOIUrl":"https://doi.org/10.1109/ICPADM.1994.414081","url":null,"abstract":"Insulation degradation of high voltage equipment has been one of the major concerns of electricity supply authorities. Amongst the many indicators that can be used to assess the insulation condition of high voltage equipment, partial discharge testing has been one of the most effective diagnostic tools for monitoring the condition of electrical insulation. A new detector has been developed for the measurement of partial discharges in high voltage equipment using radio transmission techniques. Experiments carried out in the laboratory have shown that the new detector has many advantages over the conventional PD detectors. It is believed that this is initial in the PD detection area in the world.<<ETX>>","PeriodicalId":331058,"journal":{"name":"Proceedings of 1994 4th International Conference on Properties and Applications of Dielectric Materials (ICPADM)","volume":"107 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":"124126494","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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