Pub Date : 2019-06-01DOI: 10.1109/ICDL.2019.8796803
A. Stepko, P. Lebedev-Stepanov
Computer modeling the dielectric properties of the cucurbit [7]uril (CB [7]) cavity based on the Onsager-Liptay model was carried out by analyzing the solvatochromic shift of the absorption spectrum of 1-(3ammoniumpropyl) -4-[(E) -2-(3,4-dimethoxyphenyl) ethynyl]pyridinium upon the formation of the inclusion complex with CB [7] in a water solution. The CB [7] cavity was considered as a polar environment into which the dye chromophore is placed. Positions of the maxima of the dye absorption spectra were measured experimentally in the following solvents: methanol, ethanol, i-propanol, n-butanol and water with known dielectric and optical properties. These values were used for parametrization of the Onsager-Liptay equation. Quantum-chemical calculations were used to determine molecular structures, dipole moments of the ground and excited states, and polarizability of the dye. Theoretical value of the effective dielectric permittivity of the cavity is in good agreement with the literature data derived by another method. Thus, we propose a new method for investigation the dielectric constant both in bulk liquids and in very small liquid volumes, for example, into picoliter droplets.
{"title":"Computation the Effective Dielectric Constant of Nano-Probe Local Surrounding by Solvatochromic Spectral Shift Measurement of Organic Dye Molecule","authors":"A. Stepko, P. Lebedev-Stepanov","doi":"10.1109/ICDL.2019.8796803","DOIUrl":"https://doi.org/10.1109/ICDL.2019.8796803","url":null,"abstract":"Computer modeling the dielectric properties of the cucurbit [7]uril (CB [7]) cavity based on the Onsager-Liptay model was carried out by analyzing the solvatochromic shift of the absorption spectrum of 1-(3ammoniumpropyl) -4-[(E) -2-(3,4-dimethoxyphenyl) ethynyl]pyridinium upon the formation of the inclusion complex with CB [7] in a water solution. The CB [7] cavity was considered as a polar environment into which the dye chromophore is placed. Positions of the maxima of the dye absorption spectra were measured experimentally in the following solvents: methanol, ethanol, i-propanol, n-butanol and water with known dielectric and optical properties. These values were used for parametrization of the Onsager-Liptay equation. Quantum-chemical calculations were used to determine molecular structures, dipole moments of the ground and excited states, and polarizability of the dye. Theoretical value of the effective dielectric permittivity of the cavity is in good agreement with the literature data derived by another method. Thus, we propose a new method for investigation the dielectric constant both in bulk liquids and in very small liquid volumes, for example, into picoliter droplets.","PeriodicalId":102217,"journal":{"name":"2019 IEEE 20th International Conference on Dielectric Liquids (ICDL)","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123555312","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 : 2019-06-01DOI: 10.1109/ICDL.2019.8796779
L. Calcara, M. Pompili, S. Sangiovanni, B. Pfeiffer, T. Renaudin, T. Welfonder
The IEC 61294 Technical Report, published in 1993, describes a simple test procedure to measure the PD Inception Voltage (PDIV) in insulating liquids and doesn’t cover any other items related to the PD patterns and their evolution at higher voltages. This simplified approach should be considered superseded when taking into account the several studies published in the last decades concerning the PD detection in different dielectric liquids using PD patterns and Ultra Wide Band measuring systems with the aim to find a correlation between PD phenomena, breakdown event and liquid characteristics. The use of these advanced PD patterns and Ultra Wide Band detectors may also contribute to discriminate PD in insulating liquids and PD in regular voids in oil-paper insulations.
{"title":"Advances in Measuring Partial Discharge in Insulating Liquids","authors":"L. Calcara, M. Pompili, S. Sangiovanni, B. Pfeiffer, T. Renaudin, T. Welfonder","doi":"10.1109/ICDL.2019.8796779","DOIUrl":"https://doi.org/10.1109/ICDL.2019.8796779","url":null,"abstract":"The IEC 61294 Technical Report, published in 1993, describes a simple test procedure to measure the PD Inception Voltage (PDIV) in insulating liquids and doesn’t cover any other items related to the PD patterns and their evolution at higher voltages. This simplified approach should be considered superseded when taking into account the several studies published in the last decades concerning the PD detection in different dielectric liquids using PD patterns and Ultra Wide Band measuring systems with the aim to find a correlation between PD phenomena, breakdown event and liquid characteristics. The use of these advanced PD patterns and Ultra Wide Band detectors may also contribute to discriminate PD in insulating liquids and PD in regular voids in oil-paper insulations.","PeriodicalId":102217,"journal":{"name":"2019 IEEE 20th International Conference on Dielectric Liquids (ICDL)","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116085586","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 : 2019-06-01DOI: 10.1109/ICDL.2019.8796821
B. Dikarev, G. Karasev, S. Sokolovsky, Oleksii Karasev
Liquid dielectrics are extensively used as an insulating and heat transfer agent in electrical apparatus. The electophysical properties of these insulating liquids are of vital importance to the service life of electrical equipment and have become increasingly important as operating voltages have increased to 500 kV and above and internal equipment spacing has decreased. We initially studied the current time characteristics of benzene, toluene and carbon tetrachloride under dc electric stress. The results demonstrated that the current decreased with the time, what could be explained by the creation of space charge near the electrodes. Current-voltage characteristics were constructed for different times of electrical field application. We have also conducted measurements of discharge currents, which led to obtaining the values of diffusion coefficient and space charges. From the reversal currents investigations it is possible to calculate the mobility of charge carriers. We added also the new data about reversal currents in hydrolique liquids. The model explaining the dependence of the resistivity on the distance between the electrodes is proposed.
{"title":"Space Charge Effect On The Electrophysical Characteristics Of Liquid Dielectrics","authors":"B. Dikarev, G. Karasev, S. Sokolovsky, Oleksii Karasev","doi":"10.1109/ICDL.2019.8796821","DOIUrl":"https://doi.org/10.1109/ICDL.2019.8796821","url":null,"abstract":"Liquid dielectrics are extensively used as an insulating and heat transfer agent in electrical apparatus. The electophysical properties of these insulating liquids are of vital importance to the service life of electrical equipment and have become increasingly important as operating voltages have increased to 500 kV and above and internal equipment spacing has decreased. We initially studied the current time characteristics of benzene, toluene and carbon tetrachloride under dc electric stress. The results demonstrated that the current decreased with the time, what could be explained by the creation of space charge near the electrodes. Current-voltage characteristics were constructed for different times of electrical field application. We have also conducted measurements of discharge currents, which led to obtaining the values of diffusion coefficient and space charges. From the reversal currents investigations it is possible to calculate the mobility of charge carriers. We added also the new data about reversal currents in hydrolique liquids. The model explaining the dependence of the resistivity on the distance between the electrodes is proposed.","PeriodicalId":102217,"journal":{"name":"2019 IEEE 20th International Conference on Dielectric Liquids (ICDL)","volume":"56 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114586030","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 : 2019-06-01DOI: 10.1109/ICDL.2019.8796788
M. Mazzaro, D. De Bartolomeo, M. Pompili, L. Calcara, S. Sangiovanni, F. Scatiggio, A. Valant, M. Rebolini, A. Ledda, E. Bemporad, S. Berardi, F. Mauri, M. Salvadori, A. Sturchio, M. Falconi
This paper describes the work carried out by the Italian Institutional Working Group on Natural Esters; this Group has been promoted by the University of Roma ”La Sapienza”, the National Firefighters Authority, the National Institute for Insurance against Accidents at Work (INAIL) and the Department for Geological Survey of Italy (ISPRA) with the objective of further validating the real possibility of risk mitigation for humans and environment through a more widespread use of a new generation of transformers insulated with natural ester liquids. A useful contribution to the activities of the Italian Institutional Group on Natural Esters has been also given by the participation of some of the major players in the electrical sector, such as: Italian TSO, main Distributors, Natural Ester producers and transformer manufacturers. The development of this Italian Group at international level has been the set-up of the CIGRE WG D1.68 “Natural and synthetic esters - Evaluation of the performance under fire and the impact on environment”, which is actually preparing a report on this subject. The present paper reports the main results of experimental comparative fire simulations of both mineral oil and natural esters distribution transformers.
本文介绍了意大利天然酯机构工作组所开展的工作;该小组由罗马"拉萨皮恩扎"大学、国家消防管理局、国家工伤事故保险研究所和意大利地质调查局推动，目的是进一步验证通过更广泛地使用用天然酯液体绝缘的新一代变压器，为人类和环境减轻风险的真正可能性。电力部门的一些主要参与者的参与也对意大利天然酯机构小组的活动作出了有益的贡献，例如:意大利TSO、主要分销商、天然酯生产商和变压器制造商。这个意大利集团在国际层面的发展已经建立了CIGRE WG D1.68“天然和合成酯-评估火灾下的性能和对环境的影响”，它实际上正在准备一份关于这个主题的报告。本文报道了矿物油和天然酯类配电变压器火灾模拟的主要实验对比结果。
{"title":"Fire simulation tests of mineral oil and natural esters transformers","authors":"M. Mazzaro, D. De Bartolomeo, M. Pompili, L. Calcara, S. Sangiovanni, F. Scatiggio, A. Valant, M. Rebolini, A. Ledda, E. Bemporad, S. Berardi, F. Mauri, M. Salvadori, A. Sturchio, M. Falconi","doi":"10.1109/ICDL.2019.8796788","DOIUrl":"https://doi.org/10.1109/ICDL.2019.8796788","url":null,"abstract":"This paper describes the work carried out by the Italian Institutional Working Group on Natural Esters; this Group has been promoted by the University of Roma ”La Sapienza”, the National Firefighters Authority, the National Institute for Insurance against Accidents at Work (INAIL) and the Department for Geological Survey of Italy (ISPRA) with the objective of further validating the real possibility of risk mitigation for humans and environment through a more widespread use of a new generation of transformers insulated with natural ester liquids. A useful contribution to the activities of the Italian Institutional Group on Natural Esters has been also given by the participation of some of the major players in the electrical sector, such as: Italian TSO, main Distributors, Natural Ester producers and transformer manufacturers. The development of this Italian Group at international level has been the set-up of the CIGRE WG D1.68 “Natural and synthetic esters - Evaluation of the performance under fire and the impact on environment”, which is actually preparing a report on this subject. The present paper reports the main results of experimental comparative fire simulations of both mineral oil and natural esters distribution transformers.","PeriodicalId":102217,"journal":{"name":"2019 IEEE 20th International Conference on Dielectric Liquids (ICDL)","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123504220","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 analysis of the influence of different dielectric gases on the flashover characteristics of insulators under DC voltage superimposed impulse voltage is mainly performed in this paper. In the experiment, the spacer surface charge is saturated by applying DC voltage under working temperature in advance. The flashover experiments were conducted with and without linear metal particle in pure $mathrm {SF_{6}, C_{4}F_{7}N/CO_{2}}$(4%/96%) and $mathrm {SF_{6}/N_{2}}$ (20%/80%) gas mixtures. At the same time, the surface potential distribution was measured and analyzed. The results show that the type of the gas medium is not the dominant factor of potential distribution without particle, and there is little difference in different gas environments. When metal particle defects appear on spacer surface, it will cause severe potential distortion and these regions are located around the tip of the particle and coincide with the flashover path. It also has proved that the gas insulating medium has influence on the surface charge accumulation in this circumstance. In $mathrm {C_{3}F_{7}CN/CO_{2}}$ mixture, the minimum potential value is 9954.86V, which is lower than that of others, and the decline percentage of flashover voltage is 16.82%. These indicate that $mathrm {C_{3}F_{7}CN/CO_{2}}$ is better than SF6 and its mixed gas in some respects.
{"title":"Insulation Characteristics of Spacer Filled with Different Gas insulating mediums Under Superimposed Voltage of DC and Impulse","authors":"Jingrui Wang, Zhiyuan Wang, Jian Wang, Yanan Chang, Qiuxiang Hu, Xiaoru Ni, Qingmin Li","doi":"10.1109/ICDL.2019.8796770","DOIUrl":"https://doi.org/10.1109/ICDL.2019.8796770","url":null,"abstract":"The analysis of the influence of different dielectric gases on the flashover characteristics of insulators under DC voltage superimposed impulse voltage is mainly performed in this paper. In the experiment, the spacer surface charge is saturated by applying DC voltage under working temperature in advance. The flashover experiments were conducted with and without linear metal particle in pure $mathrm {SF_{6}, C_{4}F_{7}N/CO_{2}}$(4%/96%) and $mathrm {SF_{6}/N_{2}}$ (20%/80%) gas mixtures. At the same time, the surface potential distribution was measured and analyzed. The results show that the type of the gas medium is not the dominant factor of potential distribution without particle, and there is little difference in different gas environments. When metal particle defects appear on spacer surface, it will cause severe potential distortion and these regions are located around the tip of the particle and coincide with the flashover path. It also has proved that the gas insulating medium has influence on the surface charge accumulation in this circumstance. In $mathrm {C_{3}F_{7}CN/CO_{2}}$ mixture, the minimum potential value is 9954.86V, which is lower than that of others, and the decline percentage of flashover voltage is 16.82%. These indicate that $mathrm {C_{3}F_{7}CN/CO_{2}}$ is better than SF6 and its mixed gas in some respects.","PeriodicalId":102217,"journal":{"name":"2019 IEEE 20th International Conference on Dielectric Liquids (ICDL)","volume":"93 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130052680","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 : 2019-06-01DOI: 10.1109/ICDL.2019.8796589
Sohan S. Beldar, Rohit Dolasiya, Girish A Morde, C. Narasimhan
Several researchers have claimed that Natural Esters enhance the thermal stability of insulation paper. It has been claimed that the chemical interaction accounts for slowing down of ageing of paper and enhancement of insulation life. The enhancement of paper life translates to transformer asset life enhancement. We have conducted aging studies at 120 °C on normal Kraft paper (NKP) as well as thermally upgraded Kraft paper (TUK). The results showed unambiguous development of carbonyl structure on the paper surface – both normal Kraft paper and thermally upgraded paper. These results are further corroborated with X-ray photoelectron spectroscopy (XPS) which lends further support to the formation of carbonyl structure on the paper surface. The results are interpreted in terms of transesterification reaction taking place between cellulosic hydroxyls and the carboxylate of oil. It is suggested that this interaction leads to development of hydrophobicity on the cellulose paper surface which reduces moisture uptake by paper.
{"title":"FTIR and X-Ray photoelectron spectral (XPS) evidence for interaction between natural ester and cellulose paper","authors":"Sohan S. Beldar, Rohit Dolasiya, Girish A Morde, C. Narasimhan","doi":"10.1109/ICDL.2019.8796589","DOIUrl":"https://doi.org/10.1109/ICDL.2019.8796589","url":null,"abstract":"Several researchers have claimed that Natural Esters enhance the thermal stability of insulation paper. It has been claimed that the chemical interaction accounts for slowing down of ageing of paper and enhancement of insulation life. The enhancement of paper life translates to transformer asset life enhancement. We have conducted aging studies at 120 °C on normal Kraft paper (NKP) as well as thermally upgraded Kraft paper (TUK). The results showed unambiguous development of carbonyl structure on the paper surface – both normal Kraft paper and thermally upgraded paper. These results are further corroborated with X-ray photoelectron spectroscopy (XPS) which lends further support to the formation of carbonyl structure on the paper surface. The results are interpreted in terms of transesterification reaction taking place between cellulosic hydroxyls and the carboxylate of oil. It is suggested that this interaction leads to development of hydrophobicity on the cellulose paper surface which reduces moisture uptake by paper.","PeriodicalId":102217,"journal":{"name":"2019 IEEE 20th International Conference on Dielectric Liquids (ICDL)","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134009031","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 : 2019-06-01DOI: 10.1109/ICDL.2019.8796689
Omar Amirouche
Dielectric Frequency Response Test (DFR) – FDS-Frequency Domaine Spectroscopy) of power transformers is a diagnostic tool used to assess the dielectric properties as moisture in insulating system paper and oil, power factor, oil conductivity, etc..) in the frequency range from 0.05 mHz to 1 kHz.In this paper we have selected some real case studies on some power transformers that presented problems in the insulating system during the monitoring phase on the one hand, and on the other hand, we have studied the restoration of such anomalies with targeted corrective actions aimed at improving the residual life of the transformer. In particular the following case studies are reported:–two twin transformer of 150 MVA with high furanics compounds (2FAL);–an autotransfo of 5 MVA after coils replacement in manufacturer workshop.–a transformer of 8 MVA – 132/6 kV with high moisture (6%) in paper and high dissipation factor–under vaccum reconditioning up to moisture in paper about 3 %. The advantages / effectiveness of the DFR analysis compared to the analysis of the oil standard (Karl Fisher method):•Determines the water content in the solid-paper insulation without opening the transformer•Eliminates the problem related to the interpretation of moisture in the oil and solid insulating part (active part) of the transformer.•Allows the monitoring of the paper moisture treatment, its extraction (% by weight), and the limit below which to stop the treatment.
{"title":"Moisture in power transformers DFR analysis – real cases studies on site","authors":"Omar Amirouche","doi":"10.1109/ICDL.2019.8796689","DOIUrl":"https://doi.org/10.1109/ICDL.2019.8796689","url":null,"abstract":"Dielectric Frequency Response Test (DFR) – FDS-Frequency Domaine Spectroscopy) of power transformers is a diagnostic tool used to assess the dielectric properties as moisture in insulating system paper and oil, power factor, oil conductivity, etc..) in the frequency range from 0.05 mHz to 1 kHz.In this paper we have selected some real case studies on some power transformers that presented problems in the insulating system during the monitoring phase on the one hand, and on the other hand, we have studied the restoration of such anomalies with targeted corrective actions aimed at improving the residual life of the transformer. In particular the following case studies are reported:–two twin transformer of 150 MVA with high furanics compounds (2FAL);–an autotransfo of 5 MVA after coils replacement in manufacturer workshop.–a transformer of 8 MVA – 132/6 kV with high moisture (6%) in paper and high dissipation factor–under vaccum reconditioning up to moisture in paper about 3 %. The advantages / effectiveness of the DFR analysis compared to the analysis of the oil standard (Karl Fisher method):•Determines the water content in the solid-paper insulation without opening the transformer•Eliminates the problem related to the interpretation of moisture in the oil and solid insulating part (active part) of the transformer.•Allows the monitoring of the paper moisture treatment, its extraction (% by weight), and the limit below which to stop the treatment.","PeriodicalId":102217,"journal":{"name":"2019 IEEE 20th International Conference on Dielectric Liquids (ICDL)","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134117530","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 : 2019-06-01DOI: 10.1109/ICDL.2019.8796820
M. Belyaev, N. Zubarev, O. Zubareva
Conical structures arising on the surface of a liquid with ionic conductivity in an electric field are considered taking into account the influence of both bulk and surface charges. It is demonstrated that the field distribution problem admits an exact analytical solution corresponding to the space-charge-limited current mode. The dependence of the saturation current through the conical formation on the cone apex angle, on the dielectric constant of the liquid, and on the mobilities of positive and negative ions is found. The current vanishes at zero and Taylor’s (49.3°) cone half-angles, and reaches the maximum value between them. The maximum current is shifted to higher angles with increasing dielectric constant of the medium.
{"title":"Conical structures on the surface of a liquid with ion current in the space-charge limited mode","authors":"M. Belyaev, N. Zubarev, O. Zubareva","doi":"10.1109/ICDL.2019.8796820","DOIUrl":"https://doi.org/10.1109/ICDL.2019.8796820","url":null,"abstract":"Conical structures arising on the surface of a liquid with ionic conductivity in an electric field are considered taking into account the influence of both bulk and surface charges. It is demonstrated that the field distribution problem admits an exact analytical solution corresponding to the space-charge-limited current mode. The dependence of the saturation current through the conical formation on the cone apex angle, on the dielectric constant of the liquid, and on the mobilities of positive and negative ions is found. The current vanishes at zero and Taylor’s (49.3°) cone half-angles, and reaches the maximum value between them. The maximum current is shifted to higher angles with increasing dielectric constant of the medium.","PeriodicalId":102217,"journal":{"name":"2019 IEEE 20th International Conference on Dielectric Liquids (ICDL)","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131529465","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 : 2019-06-01DOI: 10.1109/ICDL.2019.8796808
Haoxiang Zhao, Yang Li, Jia-ye Wen, Xiaowei Liu, Yanhua Han, Lu Zhang, H. Mu, Guanjun Zhang
this paper studies the dielectric property of oilpaper in high electric field, especially the effect of moisture on the dielectric loss under variable voltage at power frequency in oil-immersed paper with different moisture content. Oil-immersed paper insulation model samples with different moisture content are prepared in laboratory. Afterwards, increasing voltage and decreasing voltage tanδ-U curves of samples with different moisture content were tested under different experiment condition and a non-linear phenomenon was observed. Test results show that the tanδ-U curve is influenced by the moisture content of oil-immersed paper and test temperature. When the moisture content in the oil-immersed paper is high, the tanδ-U value is gradually increasing with the increase of the voltage. And in the process of decreasing the voltage, the tanδ-U value gradually decreases but is greater than the value at the same voltage in the process of increasing the voltage. The decreasing voltage tan tanδ-U curve is above the increasing voltage tan tanδ-U curve while these two curves overlap at high voltage and have great separation at low voltage. Moisture content changes the overall shape of the curve and the area between the two curves by influencing the transfer of charge carriers in oil-immersed paper. As water is polar, energy level and density of the trap in the oil-immersed paper with different moisture content are different. Water provides more paths for free moving charge carriers so that the accumulation and dissipation velocity of the charge carriers in Oil-immersed paper vary. The temperature doesn’t change the overall shape of the tanδ-U curve. Based on the dielectric response, the tanδ-U curve of samples with different moisture content could be expounded and the moisture Content in oil-paper insulation equipment could be evaluated by the tanδ-U curve.
{"title":"Diagnosis of Moisture Content in Oil-immersed Paper Based on Dielectric Loss with Variable Voltage at Power Frequency","authors":"Haoxiang Zhao, Yang Li, Jia-ye Wen, Xiaowei Liu, Yanhua Han, Lu Zhang, H. Mu, Guanjun Zhang","doi":"10.1109/ICDL.2019.8796808","DOIUrl":"https://doi.org/10.1109/ICDL.2019.8796808","url":null,"abstract":"this paper studies the dielectric property of oilpaper in high electric field, especially the effect of moisture on the dielectric loss under variable voltage at power frequency in oil-immersed paper with different moisture content. Oil-immersed paper insulation model samples with different moisture content are prepared in laboratory. Afterwards, increasing voltage and decreasing voltage tanδ-U curves of samples with different moisture content were tested under different experiment condition and a non-linear phenomenon was observed. Test results show that the tanδ-U curve is influenced by the moisture content of oil-immersed paper and test temperature. When the moisture content in the oil-immersed paper is high, the tanδ-U value is gradually increasing with the increase of the voltage. And in the process of decreasing the voltage, the tanδ-U value gradually decreases but is greater than the value at the same voltage in the process of increasing the voltage. The decreasing voltage tan tanδ-U curve is above the increasing voltage tan tanδ-U curve while these two curves overlap at high voltage and have great separation at low voltage. Moisture content changes the overall shape of the curve and the area between the two curves by influencing the transfer of charge carriers in oil-immersed paper. As water is polar, energy level and density of the trap in the oil-immersed paper with different moisture content are different. Water provides more paths for free moving charge carriers so that the accumulation and dissipation velocity of the charge carriers in Oil-immersed paper vary. The temperature doesn’t change the overall shape of the tanδ-U curve. Based on the dielectric response, the tanδ-U curve of samples with different moisture content could be expounded and the moisture Content in oil-paper insulation equipment could be evaluated by the tanδ-U curve.","PeriodicalId":102217,"journal":{"name":"2019 IEEE 20th International Conference on Dielectric Liquids (ICDL)","volume":"137 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132094153","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 : 2019-06-01DOI: 10.1109/ICDL.2019.8796680
P. Traoré, C. Louste, U. Seth, P. Vázquez, J. Yagoobi
In this study a full 3D numerical simulation of the flow induced by the dissociation of neutral molecules in a weakly conductive liquid between a blade shaped electrode and a vertical plane electrode is undertaken. It turns out that even in the conduction situation where neutral molecule dissociate into ions, although the flow is expected to be directed from the plane to the blade a reversed flow occurs after a transition when some circumstances are met. To the best knowledge of the authors, this intriguing phenomenon has never been reported. In this study, this unexpected behavior is analyzed, and an explanation is proposed. The conditions leading to this particular flow inversion pattern are examined and highlighted.
{"title":"Numerical study of electrically induced flow by conduction mechanism in a blade-plane configuration","authors":"P. Traoré, C. Louste, U. Seth, P. Vázquez, J. Yagoobi","doi":"10.1109/ICDL.2019.8796680","DOIUrl":"https://doi.org/10.1109/ICDL.2019.8796680","url":null,"abstract":"In this study a full 3D numerical simulation of the flow induced by the dissociation of neutral molecules in a weakly conductive liquid between a blade shaped electrode and a vertical plane electrode is undertaken. It turns out that even in the conduction situation where neutral molecule dissociate into ions, although the flow is expected to be directed from the plane to the blade a reversed flow occurs after a transition when some circumstances are met. To the best knowledge of the authors, this intriguing phenomenon has never been reported. In this study, this unexpected behavior is analyzed, and an explanation is proposed. The conditions leading to this particular flow inversion pattern are examined and highlighted.","PeriodicalId":102217,"journal":{"name":"2019 IEEE 20th International Conference on Dielectric Liquids (ICDL)","volume":"79 1-2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123431996","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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