Pub Date : 2011-09-08DOI: 10.1109/ICDL.2011.6015491
N. Bonifaci, A. Denat, V. Atrazhev, V. Shakhatov, K. von Haeften, J. Eloranta
Spectra obtained in corona discharge in liquid and in gaseous Helium are under contrastive analysis. The spectra observed in LHe are emitted by excited atoms surrounded empty cavities (bubbles). The spectra emitted in gaseous gas under high pressure have asymmetric profile due to strong perturbation of radiating atom surrounded by perturbers.
{"title":"Spectra emitted by helium excited by corona discharge","authors":"N. Bonifaci, A. Denat, V. Atrazhev, V. Shakhatov, K. von Haeften, J. Eloranta","doi":"10.1109/ICDL.2011.6015491","DOIUrl":"https://doi.org/10.1109/ICDL.2011.6015491","url":null,"abstract":"Spectra obtained in corona discharge in liquid and in gaseous Helium are under contrastive analysis. The spectra observed in LHe are emitted by excited atoms surrounded empty cavities (bubbles). The spectra emitted in gaseous gas under high pressure have asymmetric profile due to strong perturbation of radiating atom surrounded by perturbers.","PeriodicalId":364451,"journal":{"name":"2011 IEEE International Conference on Dielectric Liquids","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126434641","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 : 2011-06-26DOI: 10.1109/ICDL.2011.6015430
He-ming Ren, Jian-Hua Yang, Jingming Gao, Jun Zhang
The short pulse breakdown characteristic of water dielectric is the basis of its application in pulsed power filed. By the literature survey, the influencing factors on breakdown characteristics and the theoretical prediction of breakdown characteristic parameters in water dielectric is presented in this paper in order to provide some useful reference for the miniaturized design of high power microwave (HPM) sources.
{"title":"Analysis of short pulse breakdown in water dielectric","authors":"He-ming Ren, Jian-Hua Yang, Jingming Gao, Jun Zhang","doi":"10.1109/ICDL.2011.6015430","DOIUrl":"https://doi.org/10.1109/ICDL.2011.6015430","url":null,"abstract":"The short pulse breakdown characteristic of water dielectric is the basis of its application in pulsed power filed. By the literature survey, the influencing factors on breakdown characteristics and the theoretical prediction of breakdown characteristic parameters in water dielectric is presented in this paper in order to provide some useful reference for the miniaturized design of high power microwave (HPM) sources.","PeriodicalId":364451,"journal":{"name":"2011 IEEE International Conference on Dielectric Liquids","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127112107","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 : 2011-06-26DOI: 10.1109/ICDL.2011.6015484
R. Liao, J. Hao, Lijun Yang, S. Grzybowski
Transformer is one of the most critical equipment insuring the safe operation of power grids. The aging of insulation materials (mainly parts are the insulation oil and transformer paper) decide the operational life of the transformer. This paper is aimed at improving the anti-aging properties of power transformer via using new mineral oil/natural ester mixtures. The aging characteristics of mixed insulating oil-paper insulation and mineral oil-paper insulation were provided through 264 days' accelerated thermal aging at 110°C. The color of the oil, oil acidity, degree of polymerization (DP) of the paper and the thermal stability behavior of oil-paper insulation with different aging status were compared. Results show that the mixed insulating oil can not only restrain the oil oxidation itself, but also can restrain the aging rate of the paper immersed in the mixed insulating oil. The thermal stability of oil-paper insulation could be also improved by using the mixed insulating oil.
{"title":"Study on aging characteristics of mineral oil/natural ester mixtures-paper insulation","authors":"R. Liao, J. Hao, Lijun Yang, S. Grzybowski","doi":"10.1109/ICDL.2011.6015484","DOIUrl":"https://doi.org/10.1109/ICDL.2011.6015484","url":null,"abstract":"Transformer is one of the most critical equipment insuring the safe operation of power grids. The aging of insulation materials (mainly parts are the insulation oil and transformer paper) decide the operational life of the transformer. This paper is aimed at improving the anti-aging properties of power transformer via using new mineral oil/natural ester mixtures. The aging characteristics of mixed insulating oil-paper insulation and mineral oil-paper insulation were provided through 264 days' accelerated thermal aging at 110°C. The color of the oil, oil acidity, degree of polymerization (DP) of the paper and the thermal stability behavior of oil-paper insulation with different aging status were compared. Results show that the mixed insulating oil can not only restrain the oil oxidation itself, but also can restrain the aging rate of the paper immersed in the mixed insulating oil. The thermal stability of oil-paper insulation could be also improved by using the mixed insulating oil.","PeriodicalId":364451,"journal":{"name":"2011 IEEE International Conference on Dielectric Liquids","volume":"183 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122930137","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 : 2011-06-26DOI: 10.1109/ICDL.2011.6015472
M. Jovalekic, D. Kolb, S. Tenbohlen, L. Bates, R. Szewczyk
In recent years one can observe a higher interest in alternative dielectric materials for power transformers. These are for example natural and synthetic esters or aramid fiber based solid insulation materials. In this paper moisture saturation curves of various insulation oils are presented up to a temperature of 140°C, together with the sorption isotherms of Nomex® pressboard. These lead to adjusted equilibrium charts for moisture diagnosis of transformers with unconventional insulation systems.
{"title":"A methodology for determining water saturation limits and moisture equilibrium diagrams of alternative insulation systems","authors":"M. Jovalekic, D. Kolb, S. Tenbohlen, L. Bates, R. Szewczyk","doi":"10.1109/ICDL.2011.6015472","DOIUrl":"https://doi.org/10.1109/ICDL.2011.6015472","url":null,"abstract":"In recent years one can observe a higher interest in alternative dielectric materials for power transformers. These are for example natural and synthetic esters or aramid fiber based solid insulation materials. In this paper moisture saturation curves of various insulation oils are presented up to a temperature of 140°C, together with the sorption isotherms of Nomex® pressboard. These lead to adjusted equilibrium charts for moisture diagnosis of transformers with unconventional insulation systems.","PeriodicalId":364451,"journal":{"name":"2011 IEEE International Conference on Dielectric Liquids","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123862220","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 : 2011-06-26DOI: 10.1109/ICDL.2011.6015415
V. Pawar, A. V. Patil, S. Mehrotra
The dielectric relaxation study of acetonitrile with 1,2-dichloroethane mixture has been carried out at temperatures 15, 25, 35 and 45°C. The dielectric relaxation study of solute-solvent mixture at microwave frequencies gives information about the formation of monomers and multimers as well as interaction between the molecules of the mixture. The dielectric parameters viz. static dielectric constant (ε0) and relaxation time (τ) have been obtained by the least squares fit method. The static dielectric constant increases and relaxation time decreases with increase in concentration of acetonitrile in 1, 2-dichloroethane in the system. Excess properties and Kirkwood correlation factor of the mixtures have been determined. The static dielectric constants for the mixtures have been fitted with the modified Bruggeman model.
{"title":"Dielectric Relaxation Study of Acetonitrile with 1,2-dichloroethane Using TDR","authors":"V. Pawar, A. V. Patil, S. Mehrotra","doi":"10.1109/ICDL.2011.6015415","DOIUrl":"https://doi.org/10.1109/ICDL.2011.6015415","url":null,"abstract":"The dielectric relaxation study of acetonitrile with 1,2-dichloroethane mixture has been carried out at temperatures 15, 25, 35 and 45°C. The dielectric relaxation study of solute-solvent mixture at microwave frequencies gives information about the formation of monomers and multimers as well as interaction between the molecules of the mixture. The dielectric parameters viz. static dielectric constant (ε0) and relaxation time (τ) have been obtained by the least squares fit method. The static dielectric constant increases and relaxation time decreases with increase in concentration of acetonitrile in 1, 2-dichloroethane in the system. Excess properties and Kirkwood correlation factor of the mixtures have been determined. The static dielectric constants for the mixtures have been fitted with the modified Bruggeman model.","PeriodicalId":364451,"journal":{"name":"2011 IEEE International Conference on Dielectric Liquids","volume":"73 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121374008","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 : 2011-06-26DOI: 10.1109/ICDL.2011.6015406
D. Brocilo, Jen-Shih Chang, D. Ewing, H. Hirata, S. Matsumoto, P. Fanson
An experimental investigation has been conducted to study decane reforming by an electrohydrodynamic atomization system (EHDA). The EHDA had a hollow-tube electrode in a ceramic tube with a hollow-ring that acted as the ground electrode. The EHDA system was positioned in a grounded metallic chamber. Experiments were conducted for decane flow rates of 2 to 6 mL/min and applied dc voltages of 0 to 35 kV. The results showed that significant cracking of the decane could be achieved using the EHD atomization system. The amount of cracking depended on both the applied voltage and the decane flow rate.
{"title":"Decane reforming by a dc electrohydrodynamic atomization","authors":"D. Brocilo, Jen-Shih Chang, D. Ewing, H. Hirata, S. Matsumoto, P. Fanson","doi":"10.1109/ICDL.2011.6015406","DOIUrl":"https://doi.org/10.1109/ICDL.2011.6015406","url":null,"abstract":"An experimental investigation has been conducted to study decane reforming by an electrohydrodynamic atomization system (EHDA). The EHDA had a hollow-tube electrode in a ceramic tube with a hollow-ring that acted as the ground electrode. The EHDA system was positioned in a grounded metallic chamber. Experiments were conducted for decane flow rates of 2 to 6 mL/min and applied dc voltages of 0 to 35 kV. The results showed that significant cracking of the decane could be achieved using the EHD atomization system. The amount of cracking depended on both the applied voltage and the decane flow rate.","PeriodicalId":364451,"journal":{"name":"2011 IEEE International Conference on Dielectric Liquids","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121570308","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 : 2011-06-26DOI: 10.1109/ICDL.2011.6015409
Sotirios Missas, M. Danikas, I. Liapis
The aim of this paper is the study of various parameters affecting the ageing of transformer oil in transformers of 150/20 kV. 44 samples of oil were taken from such transformers. The transformers function in the major Athens area, Greece. Parameters, such as breakdown strength (measured with a Foster test cell, according to IEC 156/95), oil colour (with a chromometer than meets the specifications PIN 51517-ASTM P155), humidity (measured with the Karl-Fischer method, according to IEC 814), interfacial tension (which is of importance especially in the early stages of ageing, measured according to ASTM D971-91) and tanδ (with a system counting tanδ values with maximum accuracy from 0.00001 to 4.0, measured according to IEC 247) were taken into account. Transformer ageing is strictly related to the rate of ageing of its whole insulation, and mainly of the oil. Thermal and mechanical stresses have as a result the oxidation of oil and the degradation of its insulating and cooling properties. Humidity and foreign particles also consist factors contributing to the decrease of oil dielectric strength and its premature failure. Foreign particles combined with humidity result in a decrease of interfacial tension of the oil. A colour index close to 3 is not necessarily an objective indication regarding the quality of the oil. One of the main conclusions is that all aforementioned measured parameters should be taken into account. One should not base his judgment about the quality of oil on only one or two of the above parameters. Special attention is given to the way one gets the oil samples. In case of contradictory results, a repetition of sampling and the corresponding parameter measurements are required. The frequent and careful oil sampling in such transformers is recommended in order to avoid malfunctions. In general, from the transformers investigated in the context of this work, in only very few cases oil filtering was required and none of the transformers was found to function with oil requiring replacement.
{"title":"Factors affecting the ageing of transformer oil in 150 / 20 kV transformers","authors":"Sotirios Missas, M. Danikas, I. Liapis","doi":"10.1109/ICDL.2011.6015409","DOIUrl":"https://doi.org/10.1109/ICDL.2011.6015409","url":null,"abstract":"The aim of this paper is the study of various parameters affecting the ageing of transformer oil in transformers of 150/20 kV. 44 samples of oil were taken from such transformers. The transformers function in the major Athens area, Greece. Parameters, such as breakdown strength (measured with a Foster test cell, according to IEC 156/95), oil colour (with a chromometer than meets the specifications PIN 51517-ASTM P155), humidity (measured with the Karl-Fischer method, according to IEC 814), interfacial tension (which is of importance especially in the early stages of ageing, measured according to ASTM D971-91) and tanδ (with a system counting tanδ values with maximum accuracy from 0.00001 to 4.0, measured according to IEC 247) were taken into account. Transformer ageing is strictly related to the rate of ageing of its whole insulation, and mainly of the oil. Thermal and mechanical stresses have as a result the oxidation of oil and the degradation of its insulating and cooling properties. Humidity and foreign particles also consist factors contributing to the decrease of oil dielectric strength and its premature failure. Foreign particles combined with humidity result in a decrease of interfacial tension of the oil. A colour index close to 3 is not necessarily an objective indication regarding the quality of the oil. One of the main conclusions is that all aforementioned measured parameters should be taken into account. One should not base his judgment about the quality of oil on only one or two of the above parameters. Special attention is given to the way one gets the oil samples. In case of contradictory results, a repetition of sampling and the corresponding parameter measurements are required. The frequent and careful oil sampling in such transformers is recommended in order to avoid malfunctions. In general, from the transformers investigated in the context of this work, in only very few cases oil filtering was required and none of the transformers was found to function with oil requiring replacement.","PeriodicalId":364451,"journal":{"name":"2011 IEEE International Conference on Dielectric Liquids","volume":"282 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124505326","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 : 2011-06-26DOI: 10.1109/ICDL.2011.6015495
D. André
In this paper we present the main electrical conduction phenomena which can occur, from low up to very high electric field, in dielectric liquids. Such phenomena are greatly dependent on the applied electric field strength. We analyze the influence of the liquid permittivity and of the applied electric field on the concentration of free charge carriers, as well as in the bulk of the liquid than at the metal/liquid interface. The possible correlation between high field conduction phenomena and breakdown initiation is then discussed. The liquid breakdown is generally the consequence of the initiation of a localized discharge (called “streamers”) which requires a very high electric field (∼500MV/m) followed by its propagation into the liquid under a much lower electric field (∼1MV/m). Some possible mechanisms leading to this discharge initiation and then to liquid breakdown will be presented and discussed.
{"title":"Conduction and breakdown initiation in dielectric liquids","authors":"D. André","doi":"10.1109/ICDL.2011.6015495","DOIUrl":"https://doi.org/10.1109/ICDL.2011.6015495","url":null,"abstract":"In this paper we present the main electrical conduction phenomena which can occur, from low up to very high electric field, in dielectric liquids. Such phenomena are greatly dependent on the applied electric field strength. We analyze the influence of the liquid permittivity and of the applied electric field on the concentration of free charge carriers, as well as in the bulk of the liquid than at the metal/liquid interface. The possible correlation between high field conduction phenomena and breakdown initiation is then discussed. The liquid breakdown is generally the consequence of the initiation of a localized discharge (called “streamers”) which requires a very high electric field (∼500MV/m) followed by its propagation into the liquid under a much lower electric field (∼1MV/m). Some possible mechanisms leading to this discharge initiation and then to liquid breakdown will be presented and discussed.","PeriodicalId":364451,"journal":{"name":"2011 IEEE International Conference on Dielectric Liquids","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124013877","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 : 2011-06-26DOI: 10.1109/ICDL.2011.6015436
M. Saito, R. Mochizuki, Yoshihiko Nomoto
Photochromic spiropyran exhibited various colors depending on solvent polarity when exposed to ultraviolet light. Spiropyran was dissolved into a suspension consisting of polar droplets and non-polar oil. Since different absorption bands appeared in the droplets and oil, this transparent suspension turned to blue by ultraviolet irradiation and then turned to pink by stopping irradiation.
{"title":"Phase separation for creating multicolor photochromic liquid","authors":"M. Saito, R. Mochizuki, Yoshihiko Nomoto","doi":"10.1109/ICDL.2011.6015436","DOIUrl":"https://doi.org/10.1109/ICDL.2011.6015436","url":null,"abstract":"Photochromic spiropyran exhibited various colors depending on solvent polarity when exposed to ultraviolet light. Spiropyran was dissolved into a suspension consisting of polar droplets and non-polar oil. Since different absorption bands appeared in the droplets and oil, this transparent suspension turned to blue by ultraviolet irradiation and then turned to pink by stopping irradiation.","PeriodicalId":364451,"journal":{"name":"2011 IEEE International Conference on Dielectric Liquids","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130191076","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 : 2011-06-26DOI: 10.1109/ICDL.2011.6015485
Zhaotao Zhang, Jian Li, R. Liao, S. Grzybowski
Vegetable insulating oils are fire-resistant and environment-friendly liquid dielectrics. This paper presents an experiment system to simulate moisture diffusion in oil-paper insulation system based on vegetable insulating oils. A mathematical model is presented for moisture diffusion in vegetable oil-paper insulation based on the Fick's second law. By using the mathematical model and the moisture contents in vegetable insulating oils, the moisture contents in insulation paper can be predicted. The experiment and analysis results also show that the vegetable insulating oils significantly restrain moisture diffusion into insulation paper.
{"title":"Moisture diffusion invegetable oil-paper insulation","authors":"Zhaotao Zhang, Jian Li, R. Liao, S. Grzybowski","doi":"10.1109/ICDL.2011.6015485","DOIUrl":"https://doi.org/10.1109/ICDL.2011.6015485","url":null,"abstract":"Vegetable insulating oils are fire-resistant and environment-friendly liquid dielectrics. This paper presents an experiment system to simulate moisture diffusion in oil-paper insulation system based on vegetable insulating oils. A mathematical model is presented for moisture diffusion in vegetable oil-paper insulation based on the Fick's second law. By using the mathematical model and the moisture contents in vegetable insulating oils, the moisture contents in insulation paper can be predicted. The experiment and analysis results also show that the vegetable insulating oils significantly restrain moisture diffusion into insulation paper.","PeriodicalId":364451,"journal":{"name":"2011 IEEE International Conference on Dielectric Liquids","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133953699","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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