Pub Date : 2006-10-01DOI: 10.1109/CEIDP.2006.311945
J. Robertson, S. Rowland, Y. Xiong, S. Hoffmann
A number of silicone rubber composite insulators have been taken out of service after 15 years on a twin-circuit, 400 kV transmission line located in a coastal region in the south west of the UK. Visual observations and contact angle measurements are presented. The various surfaces of the insulators were degraded in a non-uniform manner, both in the rotational symmetry of the insulator and also along the length of the string. Leakage current and surface discharge measurements carried out in the laboratory are also presented. Deterioration of performance is identified, and this is found to vary along the length of the insulators.
{"title":"Field Trials of 400 kV Silicone Rubber Composite Insulators in a Coastal Location","authors":"J. Robertson, S. Rowland, Y. Xiong, S. Hoffmann","doi":"10.1109/CEIDP.2006.311945","DOIUrl":"https://doi.org/10.1109/CEIDP.2006.311945","url":null,"abstract":"A number of silicone rubber composite insulators have been taken out of service after 15 years on a twin-circuit, 400 kV transmission line located in a coastal region in the south west of the UK. Visual observations and contact angle measurements are presented. The various surfaces of the insulators were degraded in a non-uniform manner, both in the rotational symmetry of the insulator and also along the length of the string. Leakage current and surface discharge measurements carried out in the laboratory are also presented. Deterioration of performance is identified, and this is found to vary along the length of the insulators.","PeriodicalId":219099,"journal":{"name":"2006 IEEE Conference on Electrical Insulation and Dielectric Phenomena","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125422843","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 : 2006-10-01DOI: 10.1109/CEIDP.2006.312073
P. Basappa, J. Kim
Experiments have been conducted to find out whether partial discharges (PD) can characterize tree growth and whether modifying the nature of trapped charges by subjecting the samples aged by PDs to thermally stimulated discharging (TSD) procedure can alter these characteristics. Our earlier experiments have indicated that treeing could be characterized by PDs. The parameters of Weibull distribution are affected by the removal of charges by TSD. The parameters of Weibull distribution are correlated to one another and with time of aging. Several Weibull plots, TSD curves and a number of microphotographs have been studied.
{"title":"Understanding of Electrical Treeing in PMMA by Partial Discharges and Thermally Stimulated Discharges","authors":"P. Basappa, J. Kim","doi":"10.1109/CEIDP.2006.312073","DOIUrl":"https://doi.org/10.1109/CEIDP.2006.312073","url":null,"abstract":"Experiments have been conducted to find out whether partial discharges (PD) can characterize tree growth and whether modifying the nature of trapped charges by subjecting the samples aged by PDs to thermally stimulated discharging (TSD) procedure can alter these characteristics. Our earlier experiments have indicated that treeing could be characterized by PDs. The parameters of Weibull distribution are affected by the removal of charges by TSD. The parameters of Weibull distribution are correlated to one another and with time of aging. Several Weibull plots, TSD curves and a number of microphotographs have been studied.","PeriodicalId":219099,"journal":{"name":"2006 IEEE Conference on Electrical Insulation and Dielectric Phenomena","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126679888","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 : 2006-10-01DOI: 10.1109/CEIDP.2006.311948
Xingquan Huang, Linjie Zhao, Chengrong Li, Shuqi Zhang, Jisha Yao, Jun Xiong, Wei Song
Through a series of on-site hydrophobicity-measuring tests for the silicone rubber insulators operated in Henan electric power grid of China, some insulators were found having the bad hydrophobicity performance. The objective of this paper is focused on the mechanism analysis of the hydrophobicity decrease of these insulators through a series of laboratory tests. As a comparison, some new samples were also investigated. Firstly, the hydrophobicity of the tested insulators was measured using the HC method before and after washing the contamination layer away. In addition, the scanning electron microscopy (SEM) and the attenuated total reflection infrared spectroscopy (ATR-FTIR) were also used to analyze the effect of aging on the hydrophobicity of the operating insulators. The test results show that the difference of the hydrophobicity performance of silicone rubber materials between the operated insulators and the new ones is negligible. The contamination deposition is the main factors causing the surface hydrophobicity decrease of these operating insulators. Some aging phenomena were found through SEM and ATR-FTIR tests. But the relationship between these aging phenomena and the hydrophocity decrease of the operated insulators was not found.
{"title":"Mechanism analysis on hydrophobicity decrease of operating silicone rubber insulators","authors":"Xingquan Huang, Linjie Zhao, Chengrong Li, Shuqi Zhang, Jisha Yao, Jun Xiong, Wei Song","doi":"10.1109/CEIDP.2006.311948","DOIUrl":"https://doi.org/10.1109/CEIDP.2006.311948","url":null,"abstract":"Through a series of on-site hydrophobicity-measuring tests for the silicone rubber insulators operated in Henan electric power grid of China, some insulators were found having the bad hydrophobicity performance. The objective of this paper is focused on the mechanism analysis of the hydrophobicity decrease of these insulators through a series of laboratory tests. As a comparison, some new samples were also investigated. Firstly, the hydrophobicity of the tested insulators was measured using the HC method before and after washing the contamination layer away. In addition, the scanning electron microscopy (SEM) and the attenuated total reflection infrared spectroscopy (ATR-FTIR) were also used to analyze the effect of aging on the hydrophobicity of the operating insulators. The test results show that the difference of the hydrophobicity performance of silicone rubber materials between the operated insulators and the new ones is negligible. The contamination deposition is the main factors causing the surface hydrophobicity decrease of these operating insulators. Some aging phenomena were found through SEM and ATR-FTIR tests. But the relationship between these aging phenomena and the hydrophocity decrease of the operated insulators was not found.","PeriodicalId":219099,"journal":{"name":"2006 IEEE Conference on Electrical Insulation and Dielectric Phenomena","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126649139","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 : 2006-10-01DOI: 10.1109/CEIDP.2006.312097
R. Amiri, H. Hadi, M. Marich
The method of calculation of the electric field assumes that the current carrying power line conductors are straight horizontal wires. This assumption results in a model whose electric fields are distorted from those produced in reality. The influence of the geometry of the overhead line is largely noticed for the calculation of the electric field especially in the vicinity of the half span where the electric field becomes very significant. This paper presents a calculation of electric field distribution at the ground level, near of the overhead lines. To confirm our results we have calculate the electric field by three methods, the first is a software package based on Charge Simulating Method. This result is confirmed by another numerical calculation based on the use of two vectors expressing the point of calculation, this numerical method express the pace of the drivers by using the mathematical form of each phase. As third method of confirmation of result, we used a computation software named Flux 3D based on the use of the finite element method; where the shape of the drivers of phase is described by the geometrical form of the phases.
{"title":"The influence of sag in the Electric Field calculation around High Voltage Overhead transmission lines","authors":"R. Amiri, H. Hadi, M. Marich","doi":"10.1109/CEIDP.2006.312097","DOIUrl":"https://doi.org/10.1109/CEIDP.2006.312097","url":null,"abstract":"The method of calculation of the electric field assumes that the current carrying power line conductors are straight horizontal wires. This assumption results in a model whose electric fields are distorted from those produced in reality. The influence of the geometry of the overhead line is largely noticed for the calculation of the electric field especially in the vicinity of the half span where the electric field becomes very significant. This paper presents a calculation of electric field distribution at the ground level, near of the overhead lines. To confirm our results we have calculate the electric field by three methods, the first is a software package based on Charge Simulating Method. This result is confirmed by another numerical calculation based on the use of two vectors expressing the point of calculation, this numerical method express the pace of the drivers by using the mathematical form of each phase. As third method of confirmation of result, we used a computation software named Flux 3D based on the use of the finite element method; where the shape of the drivers of phase is described by the geometrical form of the phases.","PeriodicalId":219099,"journal":{"name":"2006 IEEE Conference on Electrical Insulation and Dielectric Phenomena","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116939930","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 : 2006-10-01DOI: 10.1109/CEIDP.2006.312027
T. Minagwa, H. Kohyama, Y. Yoshitomo, M. Miyashita, E. Nagao
The electrical surface resistivity of polymer base coating was investigated in arc-decomposed SF6 gas. The thickness of more than 100 mum was found necessary to prevent the adverse effect of arc-decomposed SF6 gas, which penetrated the coated film and deteriorated the insulation properties of the base material. The effect of the cure condition of the coated film was also investigated by using differential scanning calorimeter (DSC). An endothermic peak due to uncured agent, which reduced the surface resistivity in arc-decomposed SF6 gas, was observed.
{"title":"Electrical surface resistivity of organic coating resin in arc-decomposed SF6 gas","authors":"T. Minagwa, H. Kohyama, Y. Yoshitomo, M. Miyashita, E. Nagao","doi":"10.1109/CEIDP.2006.312027","DOIUrl":"https://doi.org/10.1109/CEIDP.2006.312027","url":null,"abstract":"The electrical surface resistivity of polymer base coating was investigated in arc-decomposed SF6 gas. The thickness of more than 100 mum was found necessary to prevent the adverse effect of arc-decomposed SF6 gas, which penetrated the coated film and deteriorated the insulation properties of the base material. The effect of the cure condition of the coated film was also investigated by using differential scanning calorimeter (DSC). An endothermic peak due to uncured agent, which reduced the surface resistivity in arc-decomposed SF6 gas, was observed.","PeriodicalId":219099,"journal":{"name":"2006 IEEE Conference on Electrical Insulation and Dielectric Phenomena","volume":"38 ","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"113997225","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 : 2006-10-01DOI: 10.1109/CEIDP.2006.311935
Chaowu Zhang, G. Stevens
In previous reported work we found an unusual dielectric behavior for alumina filled nanocomposites which relates to very different dynamics for adsorbed water in the materials. This was shown to depend on the polarity of the polymer matrix. In some cases, the dielectric loss peak observed in the low frequency region shifted to lower frequency with increasing temperature. This is opposite to common observed behaviour of this type of dielectric loss peak in dielectrics which generally shows a thermally activated response. In this paper we report an investigation into the dielectric responses in the frequency domain from 10-2 Hz to 106 Hz at the temperature range from -50 to 120 degC of nano-alumina filled epoxy composites. The dielectric behavior has been investigated both before and after an exhaustive drying treatment of both the nanocomposite dielectric as well as the free nano-alumina powder prior to incorporation in the matrices. The results show that the unusual dielectric behavior is only observed for both nanocomposites and nano-alumina powder before the drying treatment. After drying no unusual dielectric response is observed. This suggests that the unusual behavior is related to the location and mobility of water in materials which support a very high internal surface area.
{"title":"Dielectric Properties of Epoxy-Alumina Nanocomposites: The Effect of Absorbed Water","authors":"Chaowu Zhang, G. Stevens","doi":"10.1109/CEIDP.2006.311935","DOIUrl":"https://doi.org/10.1109/CEIDP.2006.311935","url":null,"abstract":"In previous reported work we found an unusual dielectric behavior for alumina filled nanocomposites which relates to very different dynamics for adsorbed water in the materials. This was shown to depend on the polarity of the polymer matrix. In some cases, the dielectric loss peak observed in the low frequency region shifted to lower frequency with increasing temperature. This is opposite to common observed behaviour of this type of dielectric loss peak in dielectrics which generally shows a thermally activated response. In this paper we report an investigation into the dielectric responses in the frequency domain from 10-2 Hz to 106 Hz at the temperature range from -50 to 120 degC of nano-alumina filled epoxy composites. The dielectric behavior has been investigated both before and after an exhaustive drying treatment of both the nanocomposite dielectric as well as the free nano-alumina powder prior to incorporation in the matrices. The results show that the unusual dielectric behavior is only observed for both nanocomposites and nano-alumina powder before the drying treatment. After drying no unusual dielectric response is observed. This suggests that the unusual behavior is related to the location and mobility of water in materials which support a very high internal surface area.","PeriodicalId":219099,"journal":{"name":"2006 IEEE Conference on Electrical Insulation and Dielectric Phenomena","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114863925","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 : 2006-10-01DOI: 10.1109/CEIDP.2006.311965
T. Tokoro, S. Yanagihara, M. Nagao
The application of polymer insulator has been expanded in the field of power supply and distribution system all over the world. Compared to the porcelain insulator, however, polymer insulator has been demanded to solve the subjects on a long-term reliability and on a diagnosis techniques in the real application field. Hydrophobicity of polymer surface is one of the degradation indices of polymer insulator material and is usually evaluated by using an image of sprayed water on the sample surface. In this study, dielectric measurement and image analysis are used to evaluate the hydrophobic condition and, therefore, the degradation condition of polymer surface. Using image data analysis of these water droplets, STRI's hydrophobicity class, HC from 1 to 7, is evaluated automatically. The water droplets on the sample surface are digitized and the image indexes such as size and shape factor of the droplets were evaluated. After this evaluation, 3D mapping technique is used to evaluate the HC value. Comparing of these results can define the small changes in the degradation condition of hydrophobicity of polymer insulator more accurately.
{"title":"Diagnosis of Degradation Condition of Polymer Material Using Hydrophobic Surface Analysis","authors":"T. Tokoro, S. Yanagihara, M. Nagao","doi":"10.1109/CEIDP.2006.311965","DOIUrl":"https://doi.org/10.1109/CEIDP.2006.311965","url":null,"abstract":"The application of polymer insulator has been expanded in the field of power supply and distribution system all over the world. Compared to the porcelain insulator, however, polymer insulator has been demanded to solve the subjects on a long-term reliability and on a diagnosis techniques in the real application field. Hydrophobicity of polymer surface is one of the degradation indices of polymer insulator material and is usually evaluated by using an image of sprayed water on the sample surface. In this study, dielectric measurement and image analysis are used to evaluate the hydrophobic condition and, therefore, the degradation condition of polymer surface. Using image data analysis of these water droplets, STRI's hydrophobicity class, HC from 1 to 7, is evaluated automatically. The water droplets on the sample surface are digitized and the image indexes such as size and shape factor of the droplets were evaluated. After this evaluation, 3D mapping technique is used to evaluate the HC value. Comparing of these results can define the small changes in the degradation condition of hydrophobicity of polymer insulator more accurately.","PeriodicalId":219099,"journal":{"name":"2006 IEEE Conference on Electrical Insulation and Dielectric Phenomena","volume":"2015 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121480637","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 : 2006-10-01DOI: 10.1109/CEIDP.2006.312032
T. Mito, M. Watanabe, Y. Muramoto, N. Shimizu
Electroluminescence (EL), faint light observed at electric field concentrating points is well accepted as a precursory phenomenon of the electrical tree initiation. We consider that EL is caused by electron impact. EL is considered to be closely related to material degradation; the start of EL is the start of the degradation. But the relation between EL intensity and degradation is still unclear. In this paper we'll report time-variation of EL intensity in XLPE over long-time of voltage application. When XLPE is subjected to long time voltage application of 25 hours at 5 kVrms, which is as low as EL starting voltage, the light intensity showed unexpected change. That is, even after formation of tree channel, which is very small but certain, no discharge light was observed. Instead of discharge light we observed unstable EL. This result leads us to better understanding of the early stage of degradation
{"title":"Electroluminescence Properties under Long Time Voltage Application in XLPE","authors":"T. Mito, M. Watanabe, Y. Muramoto, N. Shimizu","doi":"10.1109/CEIDP.2006.312032","DOIUrl":"https://doi.org/10.1109/CEIDP.2006.312032","url":null,"abstract":"Electroluminescence (EL), faint light observed at electric field concentrating points is well accepted as a precursory phenomenon of the electrical tree initiation. We consider that EL is caused by electron impact. EL is considered to be closely related to material degradation; the start of EL is the start of the degradation. But the relation between EL intensity and degradation is still unclear. In this paper we'll report time-variation of EL intensity in XLPE over long-time of voltage application. When XLPE is subjected to long time voltage application of 25 hours at 5 kVrms, which is as low as EL starting voltage, the light intensity showed unexpected change. That is, even after formation of tree channel, which is very small but certain, no discharge light was observed. Instead of discharge light we observed unstable EL. This result leads us to better understanding of the early stage of degradation","PeriodicalId":219099,"journal":{"name":"2006 IEEE Conference on Electrical Insulation and Dielectric Phenomena","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121614852","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 : 2006-10-01DOI: 10.1109/CEIDP.2006.311925
Zhan Huamao, Ding Lijian, Li Chengrong, L. Ming
Dielectric barrier discharge is one of the most usual methods for obtaining atmospheric pressure plasmas. It is proved theoretically that obtaining a uniform dielectric barrier discharge is strongly related to the concentration of seed electrons. Therefore, for producing enough electron concentration under a low electrical field and homogenize the discharge, some pre-ionization methods including accessorial impulse spark discharge, X rays, plasma jet have been employed. The pre-ionization effect of these methods on decreasing the applied voltage for the dielectric barrier discharge and homogenizing the discharge was investigated experimentally.
{"title":"Pre-ionization Methods for Atmospheric Pressure Discharge Controlled by Dielectric Barrier","authors":"Zhan Huamao, Ding Lijian, Li Chengrong, L. Ming","doi":"10.1109/CEIDP.2006.311925","DOIUrl":"https://doi.org/10.1109/CEIDP.2006.311925","url":null,"abstract":"Dielectric barrier discharge is one of the most usual methods for obtaining atmospheric pressure plasmas. It is proved theoretically that obtaining a uniform dielectric barrier discharge is strongly related to the concentration of seed electrons. Therefore, for producing enough electron concentration under a low electrical field and homogenize the discharge, some pre-ionization methods including accessorial impulse spark discharge, X rays, plasma jet have been employed. The pre-ionization effect of these methods on decreasing the applied voltage for the dielectric barrier discharge and homogenizing the discharge was investigated experimentally.","PeriodicalId":219099,"journal":{"name":"2006 IEEE Conference on Electrical Insulation and Dielectric Phenomena","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115131510","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 : 2006-10-01DOI: 10.1109/CEIDP.2006.311996
H. Krompholz, L. Hatfield, A. Neuber, J. Chaparro, H. Ryu, W. Justis
Gas breakdown in quasi homogeneous electric fields with amplitudes of up to 3 MV/cm is investigated. The setup consists of a RADAN 303 A pulser and pulse sheer SN 4, an impedance-matched oil-filled coaxial line with a lens-transition to a biconical line in vacuum or gas, and an axial or radial gap with a width on the order of mm, with a symmetrical arrangement on the other side of the gap. Capacitive voltage dividers allow to determine voltage across as well as conduction current through the gap, with a temporal resolution determined by the oscilloscope sampling rate of 20 GS/s and an analog bandwidth of 6 GHz. The gap capacitance charging time and voltage risetime across the gap is less than 250 ps. Previous experiments at TTU with a slightly larger risetime have shown that breakdown is governed by runaway electrons, with multi-channel formation and high ionization and light emission in a thin cathode layer only. In argon and air, time constants for the discharge development have been observed to have a minimum of around 100 ps at several 10 torr. A qualitative understanding of the observed phenomena and their dependence on gas pressure is based on explosive field emission and gaseous ionization for electron runaway conditions.
{"title":"Ultrafast gas breakdown at pressures below one atmosphere","authors":"H. Krompholz, L. Hatfield, A. Neuber, J. Chaparro, H. Ryu, W. Justis","doi":"10.1109/CEIDP.2006.311996","DOIUrl":"https://doi.org/10.1109/CEIDP.2006.311996","url":null,"abstract":"Gas breakdown in quasi homogeneous electric fields with amplitudes of up to 3 MV/cm is investigated. The setup consists of a RADAN 303 A pulser and pulse sheer SN 4, an impedance-matched oil-filled coaxial line with a lens-transition to a biconical line in vacuum or gas, and an axial or radial gap with a width on the order of mm, with a symmetrical arrangement on the other side of the gap. Capacitive voltage dividers allow to determine voltage across as well as conduction current through the gap, with a temporal resolution determined by the oscilloscope sampling rate of 20 GS/s and an analog bandwidth of 6 GHz. The gap capacitance charging time and voltage risetime across the gap is less than 250 ps. Previous experiments at TTU with a slightly larger risetime have shown that breakdown is governed by runaway electrons, with multi-channel formation and high ionization and light emission in a thin cathode layer only. In argon and air, time constants for the discharge development have been observed to have a minimum of around 100 ps at several 10 torr. A qualitative understanding of the observed phenomena and their dependence on gas pressure is based on explosive field emission and gaseous ionization for electron runaway conditions.","PeriodicalId":219099,"journal":{"name":"2006 IEEE Conference on Electrical Insulation and Dielectric Phenomena","volume":"587 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123138796","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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