Pub Date : 1999-12-01DOI: 10.1109/ICDL.1999.798971
M. Hara, J. Suehiro, H. Maeda, H. Nakashima
DC pre-breakdown phenomena and breakdown characteristics in the presence of free metallic particle in liquid nitrogen are studied experimentally. The results show that microdischarge occurs when a charged particle is approaching oppositely charged electrodes and intense microdischarge can trigger the complete breakdown of the tested gap. The breakdown voltage of uniform field gap with the free particle might severely fall below that of a point-to-plane gap without particle in liquid nitrogen.
{"title":"DC pre-breakdown phenomena and breakdown characteristics in the presence of metallic particle in liquid nitrogen","authors":"M. Hara, J. Suehiro, H. Maeda, H. Nakashima","doi":"10.1109/ICDL.1999.798971","DOIUrl":"https://doi.org/10.1109/ICDL.1999.798971","url":null,"abstract":"DC pre-breakdown phenomena and breakdown characteristics in the presence of free metallic particle in liquid nitrogen are studied experimentally. The results show that microdischarge occurs when a charged particle is approaching oppositely charged electrodes and intense microdischarge can trigger the complete breakdown of the tested gap. The breakdown voltage of uniform field gap with the free particle might severely fall below that of a point-to-plane gap without particle in liquid nitrogen.","PeriodicalId":393122,"journal":{"name":"Proceedings of 1999 IEEE 13th International Conference on Dielectric Liquids (ICDL'99) (Cat. No.99CH36213)","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127841773","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 : 1999-07-25DOI: 10.1109/ICDL.1999.798978
H. Borsi, K. Durnke, E. Gockenbach
The very good electric behaviour of insulating liquids beside their thermal and ageing stability, thermal transport and self healing capability are some of the reasons for their use in transformers. Faults in the insulation of transformers are very often accompanied by gases which can be dissolved or undissolved according to the condition of the liquid, the amount of generated gases, the size of the gas bubbles and the time the bubble needs to ascent. In this paper the gassing behaviour of different insulating liquids for transformers is introduced. Different failures are simulated inside a transformer model simultaneously. The generated dissolved and undissolved gases are detected and correlated to the failure. Beside mineral based transformer oil, a synthetic ester liquid is investigated which is a good substitute for PCB and mineral oil in transformers. The commercial names of the liquids used here are SHELL DIALA D as mineral based transformer oil and MIDEL 7131 as ester liquid. The gassing behaviour of the above mentioned liquids is compared for each failure and the results are discussed.
{"title":"Relation between faults and generated gases in transformer liquids","authors":"H. Borsi, K. Durnke, E. Gockenbach","doi":"10.1109/ICDL.1999.798978","DOIUrl":"https://doi.org/10.1109/ICDL.1999.798978","url":null,"abstract":"The very good electric behaviour of insulating liquids beside their thermal and ageing stability, thermal transport and self healing capability are some of the reasons for their use in transformers. Faults in the insulation of transformers are very often accompanied by gases which can be dissolved or undissolved according to the condition of the liquid, the amount of generated gases, the size of the gas bubbles and the time the bubble needs to ascent. In this paper the gassing behaviour of different insulating liquids for transformers is introduced. Different failures are simulated inside a transformer model simultaneously. The generated dissolved and undissolved gases are detected and correlated to the failure. Beside mineral based transformer oil, a synthetic ester liquid is investigated which is a good substitute for PCB and mineral oil in transformers. The commercial names of the liquids used here are SHELL DIALA D as mineral based transformer oil and MIDEL 7131 as ester liquid. The gassing behaviour of the above mentioned liquids is compared for each failure and the results are discussed.","PeriodicalId":393122,"journal":{"name":"Proceedings of 1999 IEEE 13th International Conference on Dielectric Liquids (ICDL'99) (Cat. No.99CH36213)","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134511256","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 : 1999-07-25DOI: 10.1109/ICDL.1999.798982
E. Mori, H. Taukioka, K. Takamoto, N. Miyamoto, T. Kobayashi, S. Kobayashi, H. Okubo
The working group in the Electric Technology Research Association (ETRA) in Japan has reviewed the actual status of conventional diagnosis by DGA in Japan and overseas. Various findings from the review are presented in this paper. (1) The required limits of detection and precision for gas-in-oil analysis are provided. (2) By classifying characteristic gases (C/sub 2/H/sub 2/, C/sub 2/H/sub 4/) which are present at the time of internal faults in a transformer and non-characteristic gases, three levels i.e., "Warning I", "Warning II" and "Trouble" are set as judgment criteria. (3) Graphical representations of diagnostic chart determined for discharge by overheating, partial discharge and arc discharge by using the ratio of gases. (4) Other conventional, diagnostic methods by specific gases are also reviewed.
{"title":"Latest diagnostic methods of gas-in-oil analysis for oil-filled transformer in Japan","authors":"E. Mori, H. Taukioka, K. Takamoto, N. Miyamoto, T. Kobayashi, S. Kobayashi, H. Okubo","doi":"10.1109/ICDL.1999.798982","DOIUrl":"https://doi.org/10.1109/ICDL.1999.798982","url":null,"abstract":"The working group in the Electric Technology Research Association (ETRA) in Japan has reviewed the actual status of conventional diagnosis by DGA in Japan and overseas. Various findings from the review are presented in this paper. (1) The required limits of detection and precision for gas-in-oil analysis are provided. (2) By classifying characteristic gases (C/sub 2/H/sub 2/, C/sub 2/H/sub 4/) which are present at the time of internal faults in a transformer and non-characteristic gases, three levels i.e., \"Warning I\", \"Warning II\" and \"Trouble\" are set as judgment criteria. (3) Graphical representations of diagnostic chart determined for discharge by overheating, partial discharge and arc discharge by using the ratio of gases. (4) Other conventional, diagnostic methods by specific gases are also reviewed.","PeriodicalId":393122,"journal":{"name":"Proceedings of 1999 IEEE 13th International Conference on Dielectric Liquids (ICDL'99) (Cat. No.99CH36213)","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122643235","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 : 1999-07-25DOI: 10.1109/ICDL.1999.798989
T. Nakagawa
The author tested space charge accumulation in the oil impregnated insulation paper for DC oil-filled cables, and found that polypropylene shows no resistivity reduction with time whereas kraft paper in polypropylene laminated paper (PPLP) does show some reduction. It is also revealed that degradation of insulation paper will be predictable by measurement of space charge.
{"title":"Measurement of space charge accumulation in PPLP","authors":"T. Nakagawa","doi":"10.1109/ICDL.1999.798989","DOIUrl":"https://doi.org/10.1109/ICDL.1999.798989","url":null,"abstract":"The author tested space charge accumulation in the oil impregnated insulation paper for DC oil-filled cables, and found that polypropylene shows no resistivity reduction with time whereas kraft paper in polypropylene laminated paper (PPLP) does show some reduction. It is also revealed that degradation of insulation paper will be predictable by measurement of space charge.","PeriodicalId":393122,"journal":{"name":"Proceedings of 1999 IEEE 13th International Conference on Dielectric Liquids (ICDL'99) (Cat. No.99CH36213)","volume":"52 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132173008","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 : 1999-07-25DOI: 10.1109/ICDL.1999.798914
P. Poovamma, S. N. Moorching
The paper details, the effect of AC and DC energisation on the flow charging characteristics of paraffinic based transformer oil. The Couette device which simulates some of the practical configurations of a transformer, mainly the duct flow condition in the transformer was employed. Flow charging phenomena was quantified by evaluating variations in the charging current, voltage buildup and accumulated charge, under varying flow velocities and energisation. The results of the investigation revealed that the above parameters increased with flow velocity and energisation. However, it was observed that with DC energisation, the polarity of the parameters evaluated depended on the polarity of the applied voltage.
{"title":"Flow electrification phenomena in paraffinic based transformer oil","authors":"P. Poovamma, S. N. Moorching","doi":"10.1109/ICDL.1999.798914","DOIUrl":"https://doi.org/10.1109/ICDL.1999.798914","url":null,"abstract":"The paper details, the effect of AC and DC energisation on the flow charging characteristics of paraffinic based transformer oil. The Couette device which simulates some of the practical configurations of a transformer, mainly the duct flow condition in the transformer was employed. Flow charging phenomena was quantified by evaluating variations in the charging current, voltage buildup and accumulated charge, under varying flow velocities and energisation. The results of the investigation revealed that the above parameters increased with flow velocity and energisation. However, it was observed that with DC energisation, the polarity of the parameters evaluated depended on the polarity of the applied voltage.","PeriodicalId":393122,"journal":{"name":"Proceedings of 1999 IEEE 13th International Conference on Dielectric Liquids (ICDL'99) (Cat. No.99CH36213)","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130166099","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 : 1999-07-20DOI: 10.1109/ICDL.1999.798905
V.F. Klimkin
A physical model of bubble stage generation with initiating an electrical discharge from anode in quasi-uniform fields, is suggested. The model implies field enhancement near the top of a sharp microtip on the electrode surface, field ionization, fast local liquid heating and microbubble spontaneous generation. The model permits us to determine a relationship between the statistical delay times of the discharge and the liquid properties, local field intensity and external pressure. The calculated statistical delay times of a discharge in n-hexane versus the external pressure are in good correlation with their experimental values.
{"title":"Bubble generation model for initiating breakdown from anode in n-hexane with quasi-uniform electrical fields","authors":"V.F. Klimkin","doi":"10.1109/ICDL.1999.798905","DOIUrl":"https://doi.org/10.1109/ICDL.1999.798905","url":null,"abstract":"A physical model of bubble stage generation with initiating an electrical discharge from anode in quasi-uniform fields, is suggested. The model implies field enhancement near the top of a sharp microtip on the electrode surface, field ionization, fast local liquid heating and microbubble spontaneous generation. The model permits us to determine a relationship between the statistical delay times of the discharge and the liquid properties, local field intensity and external pressure. The calculated statistical delay times of a discharge in n-hexane versus the external pressure are in good correlation with their experimental values.","PeriodicalId":393122,"journal":{"name":"Proceedings of 1999 IEEE 13th International Conference on Dielectric Liquids (ICDL'99) (Cat. No.99CH36213)","volume":"240 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123097952","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 : 1999-07-20DOI: 10.1109/ICDL.1999.798969
M. Nagao, S. Jayaram, M. Muramatsu, M. Kosaki
Dielectric loss measurements have been made in liquid nitrogen under different conditions to analyze the influence of flow speed during injection of liquid into the cryostat, level of air above test liquid, and waiting period before the application of voltage. The results indicate that the losses in commercial pure liquid nitrogen are in well under acceptable range for practical applications (<5/spl times/10/sup -4/). Dry air with 1% equivalent concentration of condensed oxygen in liquid nitrogen did not have any significant effect on measured losses. Some high values of tan/spl delta/ that have been measured are thought to be resulting from moisture condensation or deposition of other particulate contamination on electrode surfaces, and their effect on high field conduction.
{"title":"High field dielectric loss measurements of liquid nitrogen","authors":"M. Nagao, S. Jayaram, M. Muramatsu, M. Kosaki","doi":"10.1109/ICDL.1999.798969","DOIUrl":"https://doi.org/10.1109/ICDL.1999.798969","url":null,"abstract":"Dielectric loss measurements have been made in liquid nitrogen under different conditions to analyze the influence of flow speed during injection of liquid into the cryostat, level of air above test liquid, and waiting period before the application of voltage. The results indicate that the losses in commercial pure liquid nitrogen are in well under acceptable range for practical applications (<5/spl times/10/sup -4/). Dry air with 1% equivalent concentration of condensed oxygen in liquid nitrogen did not have any significant effect on measured losses. Some high values of tan/spl delta/ that have been measured are thought to be resulting from moisture condensation or deposition of other particulate contamination on electrode surfaces, and their effect on high field conduction.","PeriodicalId":393122,"journal":{"name":"Proceedings of 1999 IEEE 13th International Conference on Dielectric Liquids (ICDL'99) (Cat. No.99CH36213)","volume":"72 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121081099","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 : 1999-07-20DOI: 10.1109/ICDL.1999.798872
V. Pribylov
Methods of mechanics of continua are applied for studying the electrization of viscous dielectric liquids near the surface of a semiinfinite metal plane plate. The velocity of the gas is considered as given. Electrochemical reactions take place on the plate surface that possesses high conductivity. Electrization is produced by electrochemical reactions.
{"title":"Electrization of a dielectric liquid by its flow above the plane plate","authors":"V. Pribylov","doi":"10.1109/ICDL.1999.798872","DOIUrl":"https://doi.org/10.1109/ICDL.1999.798872","url":null,"abstract":"Methods of mechanics of continua are applied for studying the electrization of viscous dielectric liquids near the surface of a semiinfinite metal plane plate. The velocity of the gas is considered as given. Electrochemical reactions take place on the plate surface that possesses high conductivity. Electrization is produced by electrochemical reactions.","PeriodicalId":393122,"journal":{"name":"Proceedings of 1999 IEEE 13th International Conference on Dielectric Liquids (ICDL'99) (Cat. No.99CH36213)","volume":"63 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124705552","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 : 1999-07-20DOI: 10.1109/ICDL.1999.799000
K. Ochi, M. Todorokihara, H. Naito
Transient diffraction phenomena induced by the application of external electric field to nematic liquid crystal (4-cyano-4'-n-pentylbiphenyl) cells have been investigated. A far-field ring diffraction pattern is observed and is caused by a quasiperiodic herringbone pattern, similar in appearance to the classic Williams domain, in the nematic liquid crystal cells. The similarity and dissimilarity in the experimental features between the present; phenomena and the classic Williams domain are shown. It is also shown that the electric-field and the temperature dependences of the diffraction transients have correlation with those of current transients due to the conduction of impurity ions. It is concluded that the transient diffraction is attributable to the ion conduction via the formation of the herringbone texture.
{"title":"Transient diffraction due to ionic conduction in nematic liquid crystal cells","authors":"K. Ochi, M. Todorokihara, H. Naito","doi":"10.1109/ICDL.1999.799000","DOIUrl":"https://doi.org/10.1109/ICDL.1999.799000","url":null,"abstract":"Transient diffraction phenomena induced by the application of external electric field to nematic liquid crystal (4-cyano-4'-n-pentylbiphenyl) cells have been investigated. A far-field ring diffraction pattern is observed and is caused by a quasiperiodic herringbone pattern, similar in appearance to the classic Williams domain, in the nematic liquid crystal cells. The similarity and dissimilarity in the experimental features between the present; phenomena and the classic Williams domain are shown. It is also shown that the electric-field and the temperature dependences of the diffraction transients have correlation with those of current transients due to the conduction of impurity ions. It is concluded that the transient diffraction is attributable to the ion conduction via the formation of the herringbone texture.","PeriodicalId":393122,"journal":{"name":"Proceedings of 1999 IEEE 13th International Conference on Dielectric Liquids (ICDL'99) (Cat. No.99CH36213)","volume":"62 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125885821","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 : 1999-07-20DOI: 10.1109/ICDL.1999.798864
T. Matuszewski
The article contains further development of the author's problem. Ionization current was measured with the usage of cyclohexane mixture-silicon oil in concentration up to 20% and X-ray apparatus with alternating current up to 20 mA and voltage up to 4 kV. The measurement results of the ionization current depending on field intesting strongly react to the concentration of the mixture. The ionization current changes in an evident way depending on the lamp voltage and current.
{"title":"Research of ionization current in liquid dielectric mixtures","authors":"T. Matuszewski","doi":"10.1109/ICDL.1999.798864","DOIUrl":"https://doi.org/10.1109/ICDL.1999.798864","url":null,"abstract":"The article contains further development of the author's problem. Ionization current was measured with the usage of cyclohexane mixture-silicon oil in concentration up to 20% and X-ray apparatus with alternating current up to 20 mA and voltage up to 4 kV. The measurement results of the ionization current depending on field intesting strongly react to the concentration of the mixture. The ionization current changes in an evident way depending on the lamp voltage and current.","PeriodicalId":393122,"journal":{"name":"Proceedings of 1999 IEEE 13th International Conference on Dielectric Liquids (ICDL'99) (Cat. No.99CH36213)","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1999-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127049844","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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