Electrical breakdown phenomena in polyethylene for the point-to-plane gap configuration were investigated using a photooptical current measuring technique and a 760-ns rectangular high-voltage pulse. The waveform of the prebreakdown current in polyethylene was essentially the same as those in liquid dielectrics. Discharge from the positive point was more intense and faster than that from the negative point in longer gap spacing. A linear relationship to formative time lag and gap spacing was observed for gap length greater than some critical value, which indicates a constant propagation velocity in this region. The velocities are deduced to be 1.7 km/s for a point positive 50-kV and 0.38 km/s for a 60-kV negative point. These values agree with those for liquid dielectrics.<>
{"title":"Electro-optical measurement of prebreakdown current and breakdown time lag in polyethylene using nano-second rectangular pulse voltage","authors":"H. Yamada, S. Kimura, T. Sato","doi":"10.1109/ICSD.1989.69167","DOIUrl":"https://doi.org/10.1109/ICSD.1989.69167","url":null,"abstract":"Electrical breakdown phenomena in polyethylene for the point-to-plane gap configuration were investigated using a photooptical current measuring technique and a 760-ns rectangular high-voltage pulse. The waveform of the prebreakdown current in polyethylene was essentially the same as those in liquid dielectrics. Discharge from the positive point was more intense and faster than that from the negative point in longer gap spacing. A linear relationship to formative time lag and gap spacing was observed for gap length greater than some critical value, which indicates a constant propagation velocity in this region. The velocities are deduced to be 1.7 km/s for a point positive 50-kV and 0.38 km/s for a 60-kV negative point. These values agree with those for liquid dielectrics.<<ETX>>","PeriodicalId":184126,"journal":{"name":"Proceedings of the 3rd International Conference on Conduction and Breakdown in Solid Dielectrics","volume":"IA-17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126558415","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}
The advantages that digital signal processing offers for PD (partial discharge) measurement are discussed. A microprocessor-based system for the digital acquisition, storage and processing of PD pulses is described. Particular emphasis is placed on the apparent-charge measurement technique. It is shown that the results obtained are better than those provided by the usual PD measurement technique. A digital system can offer the following advantages over existing instrumentation: high noise suppression, high sensitivity, high accuracy, and high pulse repetition frequency.<>
{"title":"Fundamental principles and design of a digital PD-measurement system","authors":"M. Kurrat, D. Peier","doi":"10.1109/ICSD.1989.69197","DOIUrl":"https://doi.org/10.1109/ICSD.1989.69197","url":null,"abstract":"The advantages that digital signal processing offers for PD (partial discharge) measurement are discussed. A microprocessor-based system for the digital acquisition, storage and processing of PD pulses is described. Particular emphasis is placed on the apparent-charge measurement technique. It is shown that the results obtained are better than those provided by the usual PD measurement technique. A digital system can offer the following advantages over existing instrumentation: high noise suppression, high sensitivity, high accuracy, and high pulse repetition frequency.<<ETX>>","PeriodicalId":184126,"journal":{"name":"Proceedings of the 3rd International Conference on Conduction and Breakdown in Solid Dielectrics","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125256620","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}
In order to study systematically the relationship between mechanical properties and tree initiation and growth, a range of mechanical properties was obtained by the plasticization of the original polyester resin by the addition of controlled amounts of a plasticizing polyester resin (Crystic 586). It was found that an initial mechanical stress is necessary for the relatively easy initiation and growth of trees, casting light on the problem reported in earlier work of explaining the development of permanent mechanical stress in polyester specimens under the application of the electrostatic cyclical forces produced by an alternative electric field. Progressive plasticization of the polyester resin reduces the initial stress produced in the specimens during manufacture, and the initiation time is progressively increased as a consequence. Two conflicting mechanisms act in determining the dependence of tree growth on degree of plasticization. On one hand, increased plasticization reduces the internal stress and will reduce tree growth. On the other, plasticization decreases the fracture toughness, and propagation of trees by mechanical fracture will be enhanced.<>
{"title":"Dependence of electrical tree inception and growth on mechanical properties","authors":"D. Auckland, B. Varlow","doi":"10.1109/ICSD.1989.69254","DOIUrl":"https://doi.org/10.1109/ICSD.1989.69254","url":null,"abstract":"In order to study systematically the relationship between mechanical properties and tree initiation and growth, a range of mechanical properties was obtained by the plasticization of the original polyester resin by the addition of controlled amounts of a plasticizing polyester resin (Crystic 586). It was found that an initial mechanical stress is necessary for the relatively easy initiation and growth of trees, casting light on the problem reported in earlier work of explaining the development of permanent mechanical stress in polyester specimens under the application of the electrostatic cyclical forces produced by an alternative electric field. Progressive plasticization of the polyester resin reduces the initial stress produced in the specimens during manufacture, and the initiation time is progressively increased as a consequence. Two conflicting mechanisms act in determining the dependence of tree growth on degree of plasticization. On one hand, increased plasticization reduces the internal stress and will reduce tree growth. On the other, plasticization decreases the fracture toughness, and propagation of trees by mechanical fracture will be enhanced.<<ETX>>","PeriodicalId":184126,"journal":{"name":"Proceedings of the 3rd International Conference on Conduction and Breakdown in Solid Dielectrics","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130167842","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}
A model for the breakdown of a polymer subject to a strong electric field that views this phenomenon as the result of monopolar charge injection is presented. The starting assumption is that there is a relationship between breakdown and the onset of negative differential conduction (dj/dE>
{"title":"Model for partial breakdown of polymer","authors":"S. Gluchowski","doi":"10.1109/ICSD.1989.69168","DOIUrl":"https://doi.org/10.1109/ICSD.1989.69168","url":null,"abstract":"A model for the breakdown of a polymer subject to a strong electric field that views this phenomenon as the result of monopolar charge injection is presented. The starting assumption is that there is a relationship between breakdown and the onset of negative differential conduction (dj/dE<or=0). This effect can result in a critical electric field and, at a lower field, can increase the current density. It is suggested that the model can describe not only the breakdown process in polymer layers and the needle test but also ageing breakdown, e.g. that induced by partial discharges.<<ETX>>","PeriodicalId":184126,"journal":{"name":"Proceedings of the 3rd International Conference on Conduction and Breakdown in Solid Dielectrics","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132435896","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}
A. Ozawa, S. Mikami, K. Nitta, M. Shinmura, S. Washizu, Y. Wada
The electrical properties of native and mercerized cellulose are compared. The DC conductivity, complex dielectric constant in the frequency range from 0.1 Hz to 10 MHz, and piezoelectric constant have been measured for native and mercerized samples as functions of water content. The dielectric increment Delta epsilon of the mercerized sample, as obtained from Cole-Cole plots, is more than twice as large as that of native cellulose. This is attributed to the fact that by mercerization, chains in the amorphous phase are more regularly packed, and the correlation length for orientation of OH groups increases, resulting in an increase of Delta epsilon . In addition, a smaller piezoelectric constant is indicated for the mercerized sample.<>
{"title":"Electrical conduction and polarization in cellulose in relation to its water content","authors":"A. Ozawa, S. Mikami, K. Nitta, M. Shinmura, S. Washizu, Y. Wada","doi":"10.1109/ICSD.1989.69153","DOIUrl":"https://doi.org/10.1109/ICSD.1989.69153","url":null,"abstract":"The electrical properties of native and mercerized cellulose are compared. The DC conductivity, complex dielectric constant in the frequency range from 0.1 Hz to 10 MHz, and piezoelectric constant have been measured for native and mercerized samples as functions of water content. The dielectric increment Delta epsilon of the mercerized sample, as obtained from Cole-Cole plots, is more than twice as large as that of native cellulose. This is attributed to the fact that by mercerization, chains in the amorphous phase are more regularly packed, and the correlation length for orientation of OH groups increases, resulting in an increase of Delta epsilon . In addition, a smaller piezoelectric constant is indicated for the mercerized sample.<<ETX>>","PeriodicalId":184126,"journal":{"name":"Proceedings of the 3rd International Conference on Conduction and Breakdown in Solid Dielectrics","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134633560","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}
The use of Weibull statistics to study dielectric failure is discussed. Fractal processes involved in breakdown are considered, with particular emphasis on the stochastic progress of a filamentary discharge or conducting path. Here fluctuations in the length at a given time will lead to a Weibull statistic in time. Electrical trees are used to illustrate some of the points discussed.<>
{"title":"Fractal processes and Weibull statistics","authors":"L.A. Dissdo","doi":"10.1109/ICSD.1989.69269","DOIUrl":"https://doi.org/10.1109/ICSD.1989.69269","url":null,"abstract":"The use of Weibull statistics to study dielectric failure is discussed. Fractal processes involved in breakdown are considered, with particular emphasis on the stochastic progress of a filamentary discharge or conducting path. Here fluctuations in the length at a given time will lead to a Weibull statistic in time. Electrical trees are used to illustrate some of the points discussed.<<ETX>>","PeriodicalId":184126,"journal":{"name":"Proceedings of the 3rd International Conference on Conduction and Breakdown in Solid Dielectrics","volume":"199 5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115679970","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}
The authors investigated the relationship between the density of oxidation products and the temperature dependence of tan delta in LDPE (low-density polyethylene) films. From a comparison of the temperature dependence of tan delta of PE in XLPE (cross-linked PE) cable with that of tan delta in PE film samples, it was found that tan delta gives accurate information about the oxidation in the insulating layer of the cable. The temperature dependence of tan delta in the oxidized PE film has a peak around 0 degrees C, which is caused by the motion of the polar group. After oxidation has begun, tan delta increases to above 40 degrees C. This is attributed to the motion of a small section produced by chain scission. The increase of tan delta as a function of the density of oxidation products is obtained.<>
{"title":"Diagnosis of oxidation in XLPE cable by tan delta characteristics","authors":"N. Shimizu, N. Hirano, K. Horii","doi":"10.1109/ICSD.1989.69202","DOIUrl":"https://doi.org/10.1109/ICSD.1989.69202","url":null,"abstract":"The authors investigated the relationship between the density of oxidation products and the temperature dependence of tan delta in LDPE (low-density polyethylene) films. From a comparison of the temperature dependence of tan delta of PE in XLPE (cross-linked PE) cable with that of tan delta in PE film samples, it was found that tan delta gives accurate information about the oxidation in the insulating layer of the cable. The temperature dependence of tan delta in the oxidized PE film has a peak around 0 degrees C, which is caused by the motion of the polar group. After oxidation has begun, tan delta increases to above 40 degrees C. This is attributed to the motion of a small section produced by chain scission. The increase of tan delta as a function of the density of oxidation products is obtained.<<ETX>>","PeriodicalId":184126,"journal":{"name":"Proceedings of the 3rd International Conference on Conduction and Breakdown in Solid Dielectrics","volume":"594 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114601190","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}
The transient leakage current of XLPE (cross-linked polyethylene) cables to which a DC voltage was applied was studied under different temperatures and applied electric fields. The cables used were commercial XLPE cables with inner and outer semiconducting layers which were extruded in one operation together with the insulation layer and cured in a water vapor cross-linking unit. The thickness of the XLPE insulation was 2.5 mm and the inner diameter of the outer semiconducting layer was 17.8 mm. The ranges for the electric fields were from 3 to about 30 MV/m and for the temperatures from room temperature to about 90 degrees C. The results demonstrate the complexity of the electric conduction in XLPE and give further evidence that the conduction is space charge limited, injection controlled, and very strongly dependent on the externally applied field and, especially, the cable temperature. The degree of complexity in the electric conduction of realistic cables increases when the cable is not isothermally heated and when there is a temperature gradient between the conductor and sheath. An argument between existing theories and experiments is found.<>
{"title":"DC conduction of polymeric insulation of medium voltage cables","authors":"A. Vlastós","doi":"10.1109/ICSD.1989.69206","DOIUrl":"https://doi.org/10.1109/ICSD.1989.69206","url":null,"abstract":"The transient leakage current of XLPE (cross-linked polyethylene) cables to which a DC voltage was applied was studied under different temperatures and applied electric fields. The cables used were commercial XLPE cables with inner and outer semiconducting layers which were extruded in one operation together with the insulation layer and cured in a water vapor cross-linking unit. The thickness of the XLPE insulation was 2.5 mm and the inner diameter of the outer semiconducting layer was 17.8 mm. The ranges for the electric fields were from 3 to about 30 MV/m and for the temperatures from room temperature to about 90 degrees C. The results demonstrate the complexity of the electric conduction in XLPE and give further evidence that the conduction is space charge limited, injection controlled, and very strongly dependent on the externally applied field and, especially, the cable temperature. The degree of complexity in the electric conduction of realistic cables increases when the cable is not isothermally heated and when there is a temperature gradient between the conductor and sheath. An argument between existing theories and experiments is found.<<ETX>>","PeriodicalId":184126,"journal":{"name":"Proceedings of the 3rd International Conference on Conduction and Breakdown in Solid Dielectrics","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116927357","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}
A model is developed for a theoretical description of self-healing breakdowns in organic dielectrics. The spatiotemporal distribution of potential and current during the self-healing breakdown is first investigated, and then the energy converted for the evaporation and ionization of electrode metal as well as for gas-dynamic decomposition of the material is determined. The gas formation results may be used to compute graphite deposition in the insulating areas.<>
{"title":"Modelling of physical and chemical processes in self-healing breakdowns in organic dielectric materials","authors":"J. Kammermaier, G. Rittmayer, S. Birkle","doi":"10.1109/ICSD.1989.69245","DOIUrl":"https://doi.org/10.1109/ICSD.1989.69245","url":null,"abstract":"A model is developed for a theoretical description of self-healing breakdowns in organic dielectrics. The spatiotemporal distribution of potential and current during the self-healing breakdown is first investigated, and then the energy converted for the evaporation and ionization of electrode metal as well as for gas-dynamic decomposition of the material is determined. The gas formation results may be used to compute graphite deposition in the insulating areas.<<ETX>>","PeriodicalId":184126,"journal":{"name":"Proceedings of the 3rd International Conference on Conduction and Breakdown in Solid Dielectrics","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116291082","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}
The author presents test results on partial discharge (PD) intensity in a metal-gas-gap-solid dielectric arrangement at 101.3 kPa and 50.6 kPa. The test was carried out for AC and step voltages. The measurements reveal that the PD generation process in this arrangement is of streamer-plus-surface-discharge character.<>
{"title":"Partial discharge mechanism in a series insulating structure metal-gas gap-solid dielectric","authors":"R. Zybert","doi":"10.1109/ICSD.1989.69230","DOIUrl":"https://doi.org/10.1109/ICSD.1989.69230","url":null,"abstract":"The author presents test results on partial discharge (PD) intensity in a metal-gas-gap-solid dielectric arrangement at 101.3 kPa and 50.6 kPa. The test was carried out for AC and step voltages. The measurements reveal that the PD generation process in this arrangement is of streamer-plus-surface-discharge character.<<ETX>>","PeriodicalId":184126,"journal":{"name":"Proceedings of the 3rd International Conference on Conduction and Breakdown in Solid Dielectrics","volume":"143 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116882755","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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