Pub Date : 2017-06-01DOI: 10.1109/ICDL.2017.8124643
Patrick Rumpelt, F. Jenau
The consideration of alternative insulating oils, including Midel7131 (synthetic oil) and FR3 (vegetable oil) for an application in HVDC transformers is new. This observation supports the idea to transport clean and sustainable energy over long distances to the consumers with converter transformers, which also are equipped with sustainable, environmentally responsible insulating oils. The necessary knowledge of the conductivity behavior is purpose in current investigations [1,2]. The investigations complement the alternative insulating oils with the use of various electrode materials. Copper for example plays an important role to image a more realistic arrangement. Other electrode materials which examined here are aluminum, stainless steel and brass.
{"title":"Investigation on conductivity measurement of alternative insulating oils in conjunction with different electrode materials under DC stress","authors":"Patrick Rumpelt, F. Jenau","doi":"10.1109/ICDL.2017.8124643","DOIUrl":"https://doi.org/10.1109/ICDL.2017.8124643","url":null,"abstract":"The consideration of alternative insulating oils, including Midel7131 (synthetic oil) and FR3 (vegetable oil) for an application in HVDC transformers is new. This observation supports the idea to transport clean and sustainable energy over long distances to the consumers with converter transformers, which also are equipped with sustainable, environmentally responsible insulating oils. The necessary knowledge of the conductivity behavior is purpose in current investigations [1,2]. The investigations complement the alternative insulating oils with the use of various electrode materials. Copper for example plays an important role to image a more realistic arrangement. Other electrode materials which examined here are aluminum, stainless steel and brass.","PeriodicalId":439228,"journal":{"name":"2017 IEEE 19th International Conference on Dielectric Liquids (ICDL)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130463058","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 : 2017-06-01DOI: 10.1109/ICDL.2017.8124710
T. Münster, O. Gratz, E. Gockenbach, P. Werle, J. Friedel, A. Hilker
The main goal of this research was the comparison of the impregnation behavior of a new oil, based on the gas-to-liquids process, with a mineral oil, which should be representative for standard mineral oils used in transformers today. The investigation and comparison were made by dielectric measurements with a flat pressboard with a thickness of 0.5 mm and 3 mm as a sample. Additionally wraps with a layer thickness of 6.25 mm, made from kraft paper in cylinders with a thickness of 0.15 mm and an aluminum cylinder as a rack, were investigated. Because of the different geometric shapes of the samples the investigations were made with two different types of electrode assemblies. The measurement of the dielectric dissipation factor was performed with the method of Frequency Domain Spectroscopy (FDS) as well as with the Polarization and Depolarization Current (PDC). The obtained results show that both oils have a similar behavior of the dissipation factor for different samples and temperatures and so they show a similar impregnation behavior. Therefore, it could be considered that the diagnostic methods for dielectric measurements could be also applied to the new GTL based oil.
{"title":"Investigation on the impregnation characteristics of a new GTL based synthetic insulating fluid","authors":"T. Münster, O. Gratz, E. Gockenbach, P. Werle, J. Friedel, A. Hilker","doi":"10.1109/ICDL.2017.8124710","DOIUrl":"https://doi.org/10.1109/ICDL.2017.8124710","url":null,"abstract":"The main goal of this research was the comparison of the impregnation behavior of a new oil, based on the gas-to-liquids process, with a mineral oil, which should be representative for standard mineral oils used in transformers today. The investigation and comparison were made by dielectric measurements with a flat pressboard with a thickness of 0.5 mm and 3 mm as a sample. Additionally wraps with a layer thickness of 6.25 mm, made from kraft paper in cylinders with a thickness of 0.15 mm and an aluminum cylinder as a rack, were investigated. Because of the different geometric shapes of the samples the investigations were made with two different types of electrode assemblies. The measurement of the dielectric dissipation factor was performed with the method of Frequency Domain Spectroscopy (FDS) as well as with the Polarization and Depolarization Current (PDC). The obtained results show that both oils have a similar behavior of the dissipation factor for different samples and temperatures and so they show a similar impregnation behavior. Therefore, it could be considered that the diagnostic methods for dielectric measurements could be also applied to the new GTL based oil.","PeriodicalId":439228,"journal":{"name":"2017 IEEE 19th International Conference on Dielectric Liquids (ICDL)","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132730727","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 : 2017-06-01DOI: 10.1109/ICDL.2017.8124709
Yafei Li, Qinxue Yu, Chen Zhang, Fei Li, Jie Yang, Liangbin Ai, Haiyan Jiang, L. Zhong
Natural ester as a substitute for mineral insulating oil has been used more and more widely in distribution transformers and large power transformers. The reliable operation of the natural ester transformer is essential to the safety and stability of the power grid. And the safe operation of the natural ester transformer relays the good dielectric properties of oil-pressboard insulation. In recent, the effect of moisture content on the dielectric properties of natural ester has been studied, while the research on the influence of moisture content on dielectric properties of pressboard impregnated is not detailed. In this paper, the temperature characteristics of permittivity, dissipation factor and resistivity at power frequency of pressboard impregnated respectively both in mineral insulating oil and natural ester with the moisture content about from 0.2% to 6% were studied. And the authors also studied the AC breakdown characteristic of oil-impregnated pressboard. The results were important for the safe and reliable operation of natural ester transformers.
{"title":"Influence of moisture content on dielectric properties of pressboard impregnated in mineral insulating oil and natural ester","authors":"Yafei Li, Qinxue Yu, Chen Zhang, Fei Li, Jie Yang, Liangbin Ai, Haiyan Jiang, L. Zhong","doi":"10.1109/ICDL.2017.8124709","DOIUrl":"https://doi.org/10.1109/ICDL.2017.8124709","url":null,"abstract":"Natural ester as a substitute for mineral insulating oil has been used more and more widely in distribution transformers and large power transformers. The reliable operation of the natural ester transformer is essential to the safety and stability of the power grid. And the safe operation of the natural ester transformer relays the good dielectric properties of oil-pressboard insulation. In recent, the effect of moisture content on the dielectric properties of natural ester has been studied, while the research on the influence of moisture content on dielectric properties of pressboard impregnated is not detailed. In this paper, the temperature characteristics of permittivity, dissipation factor and resistivity at power frequency of pressboard impregnated respectively both in mineral insulating oil and natural ester with the moisture content about from 0.2% to 6% were studied. And the authors also studied the AC breakdown characteristic of oil-impregnated pressboard. The results were important for the safe and reliable operation of natural ester transformers.","PeriodicalId":439228,"journal":{"name":"2017 IEEE 19th International Conference on Dielectric Liquids (ICDL)","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"113975707","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 : 2017-06-01DOI: 10.1109/ICDL.2017.8124713
J. Hao, R. Liao, Yanqing Li, M. Dan, Lijun Yang
The cellulose particles bridging phenomenon under the DC electric field needed to be analysed. This is useful for further understanding the insulation failure and guiding the structure design of transformer using natural ester in the future. The images of cellulose particles accumulation and leak current for contaminated mineral oil and natural ester were compared under different DC electrical field strength using plate-plate electrode system. Results show that the formation process of cellulose particles bridge in mineral oil is much easier to its formation in natural ester, and the bridges in mineral oil were thicker than that in natural ester. The leak current in both types of oil increase with the rising of electrical field strength, however, the contaminated mineral oil has much higher leak current than the contaminated natural ester at the same electrical stress. The completed bridge contributes a lot to the leak current. The effect of cellulose particles on the conduction property of natural ester is weaker than that of mineral oil.
{"title":"A comparative study of the particle accumulation in natural ester and mineral oil under DC electric field","authors":"J. Hao, R. Liao, Yanqing Li, M. Dan, Lijun Yang","doi":"10.1109/ICDL.2017.8124713","DOIUrl":"https://doi.org/10.1109/ICDL.2017.8124713","url":null,"abstract":"The cellulose particles bridging phenomenon under the DC electric field needed to be analysed. This is useful for further understanding the insulation failure and guiding the structure design of transformer using natural ester in the future. The images of cellulose particles accumulation and leak current for contaminated mineral oil and natural ester were compared under different DC electrical field strength using plate-plate electrode system. Results show that the formation process of cellulose particles bridge in mineral oil is much easier to its formation in natural ester, and the bridges in mineral oil were thicker than that in natural ester. The leak current in both types of oil increase with the rising of electrical field strength, however, the contaminated mineral oil has much higher leak current than the contaminated natural ester at the same electrical stress. The completed bridge contributes a lot to the leak current. The effect of cellulose particles on the conduction property of natural ester is weaker than that of mineral oil.","PeriodicalId":439228,"journal":{"name":"2017 IEEE 19th International Conference on Dielectric Liquids (ICDL)","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114461897","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 : 2017-06-01DOI: 10.1109/ICDL.2017.8124714
J. S. Chahal, C. Reddy
The power transformers are vital components in the transmission system. In transformers, mineral oil based insulating fluids are used which are non-biodegradable, therefore disposing the aged mineral oils is very challenging. From the last few years, the power utilities all over the world have started exploring biodegradable insulating fluids as alternatives to currently available mineral oil based insulating fluids. The insulating oil is characterized by the properties such as high breakdown voltage (BDV), high flash point and low pour point among others. The vegetable oils which have some good physical, chemical and dielectric properties are sunflower oil, canola oil, palm oil, rapeseed oil, soybean oil, olive oil and mustard oil. Except for mustard oil, good literature is available for various thermal, dielectric and aging tests on these oils. Various researchers have demonstrated that adding nanoparticles to base fluids can enhance thermal properties of insulating oils and also increases life of kraft paper or press board (used in transformers) compared to mineral oils. The present investigation is to determine the effect of temperature on the BDV of mustard oil based nanofluids. In the present work Al2O3 (size < 50nm) nanoparticles are used to prepare mustard oil based nanoinsulating fluids. The prepared nano fluids had been tested for its BDV strength at different temperatures.
{"title":"Investigations on mustard oil for its suitability as insulating fluid in transformers","authors":"J. S. Chahal, C. Reddy","doi":"10.1109/ICDL.2017.8124714","DOIUrl":"https://doi.org/10.1109/ICDL.2017.8124714","url":null,"abstract":"The power transformers are vital components in the transmission system. In transformers, mineral oil based insulating fluids are used which are non-biodegradable, therefore disposing the aged mineral oils is very challenging. From the last few years, the power utilities all over the world have started exploring biodegradable insulating fluids as alternatives to currently available mineral oil based insulating fluids. The insulating oil is characterized by the properties such as high breakdown voltage (BDV), high flash point and low pour point among others. The vegetable oils which have some good physical, chemical and dielectric properties are sunflower oil, canola oil, palm oil, rapeseed oil, soybean oil, olive oil and mustard oil. Except for mustard oil, good literature is available for various thermal, dielectric and aging tests on these oils. Various researchers have demonstrated that adding nanoparticles to base fluids can enhance thermal properties of insulating oils and also increases life of kraft paper or press board (used in transformers) compared to mineral oils. The present investigation is to determine the effect of temperature on the BDV of mustard oil based nanofluids. In the present work Al2O3 (size < 50nm) nanoparticles are used to prepare mustard oil based nanoinsulating fluids. The prepared nano fluids had been tested for its BDV strength at different temperatures.","PeriodicalId":439228,"journal":{"name":"2017 IEEE 19th International Conference on Dielectric Liquids (ICDL)","volume":"56 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128478719","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 : 2017-06-01DOI: 10.1109/ICDL.2017.8124637
Yangming Wang, Xiaolong Li, Tie-Min Wang, Haiyang Shi, Z. Gu, Weigen Chen, Fu Wan
To evaluate the thermal degradation of oil-paper insulation, analyzing the furfural dissolved in transformer oil is determined as an important method. Surface enhanced Raman spectroscopy (SERS) is used to detect the concentration of furfural, which not only overcomes the shortcomings of the traditional detection methods, but also realizes nondestructive testing. In this paper, SERS for detecting the furfural in transformer oil was investigated. we used Electrochemical displacement to synthesize the two-dimensional Ag Nano-branch on copper foil, and then applied for measuring oil samples with different furfural concentrations by SERS. The SERS signal of furfural was used for qualitative and quantitative analysis at ∼931 cm−1, and the mathematical model was constructed, depending on the Raman peak intensity ratios Ι931/Ι770 and furfural concentrations, basing on the least squares method. As a result, without complex preprocessing steps, SERS can detect the transformer oil's furfural concentration quantitatively. Therefore, it proposes a new method to detect furfural concentration in transformer oil with fast in-situ capability.
{"title":"Furfural analysis in transformer oil using silver nano-branch surface-enhanced Raman spectroscopy","authors":"Yangming Wang, Xiaolong Li, Tie-Min Wang, Haiyang Shi, Z. Gu, Weigen Chen, Fu Wan","doi":"10.1109/ICDL.2017.8124637","DOIUrl":"https://doi.org/10.1109/ICDL.2017.8124637","url":null,"abstract":"To evaluate the thermal degradation of oil-paper insulation, analyzing the furfural dissolved in transformer oil is determined as an important method. Surface enhanced Raman spectroscopy (SERS) is used to detect the concentration of furfural, which not only overcomes the shortcomings of the traditional detection methods, but also realizes nondestructive testing. In this paper, SERS for detecting the furfural in transformer oil was investigated. we used Electrochemical displacement to synthesize the two-dimensional Ag Nano-branch on copper foil, and then applied for measuring oil samples with different furfural concentrations by SERS. The SERS signal of furfural was used for qualitative and quantitative analysis at ∼931 cm−1, and the mathematical model was constructed, depending on the Raman peak intensity ratios Ι931/Ι770 and furfural concentrations, basing on the least squares method. As a result, without complex preprocessing steps, SERS can detect the transformer oil's furfural concentration quantitatively. Therefore, it proposes a new method to detect furfural concentration in transformer oil with fast in-situ capability.","PeriodicalId":439228,"journal":{"name":"2017 IEEE 19th International Conference on Dielectric Liquids (ICDL)","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128073809","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 : 2017-06-01DOI: 10.1109/ICDL.2017.8124674
S. Khandan, S. Tenbohlen, C. Breuer, R. Lebreton
The focus of the present numerical study is on the temperature distribution and the fluid flow of an oil cooled winding of a power transformer. The experimental setup consists of three passes of a zig-zag disc type winding, in which losses are modeled by heating cartridges in each winding segment. Precise temperature sensors measure the temperature of each turn. The laboratory setup allows the exact control of the boundary conditions, e.g. the oil flow rate and the inlet temperature. Furthermore, a simulation is carried out with a free open source computational fluid dynamics solver OpenFOAM and validated with the experimental results. The good agreement of the simulation results with experimental measurements validates the model. The model utilizes the turbulent flow for the different mass flow rates of the oil.
{"title":"CFD study of fluid flow and temperature distributions in a power transformer winding","authors":"S. Khandan, S. Tenbohlen, C. Breuer, R. Lebreton","doi":"10.1109/ICDL.2017.8124674","DOIUrl":"https://doi.org/10.1109/ICDL.2017.8124674","url":null,"abstract":"The focus of the present numerical study is on the temperature distribution and the fluid flow of an oil cooled winding of a power transformer. The experimental setup consists of three passes of a zig-zag disc type winding, in which losses are modeled by heating cartridges in each winding segment. Precise temperature sensors measure the temperature of each turn. The laboratory setup allows the exact control of the boundary conditions, e.g. the oil flow rate and the inlet temperature. Furthermore, a simulation is carried out with a free open source computational fluid dynamics solver OpenFOAM and validated with the experimental results. The good agreement of the simulation results with experimental measurements validates the model. The model utilizes the turbulent flow for the different mass flow rates of the oil.","PeriodicalId":439228,"journal":{"name":"2017 IEEE 19th International Conference on Dielectric Liquids (ICDL)","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133346093","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 : 2017-06-01DOI: 10.1109/ICDL.2017.8124687
Chenxing Wang, Xuezhong Liu, Xianrong Wang, Ning Liu, Xiuying Jiao, Lei Liu
The deionized water dielectric is widely used as the cooling medium of the inner cooling system for HV converter valves. Theoretically, the electrolytic current in the cooling water is considered as one of the predominant causes of the corrosion of the aluminum heat sinks. The distribution of the electrolytic current inside the heat sink is revealed by simulating calculation. Corrosion tests with aluminum flake samples in simulated field conditions were conducted. The simulation results show that the electric field distortion around the grading electrode is the leading cause of the electrolytic current through the heat sink. The electrolytic current up to 10.82 μA are mainly collected by the 3.7-mm-wide area near the water inlet/outlet of the heat sink. Corrosion tests indicate that the electrolytic current has aggravated the corrosion of the heat sink in different ways. In the presence of anodic current, pit corrosion is observed due to stray-current corrosion. Whereas when cathodic current conducts through the heat sink, general corrosion occurs as a result of the aggregation of hydroxide ion. Further calculation reveals that over 95 percent of the anodic electrolytic current has contributed to the stray-current corrosion of the heat sink.
{"title":"Effects of low electric current in deionized water dielectric on corrosion of aluminum heat sinks in HV converter valves","authors":"Chenxing Wang, Xuezhong Liu, Xianrong Wang, Ning Liu, Xiuying Jiao, Lei Liu","doi":"10.1109/ICDL.2017.8124687","DOIUrl":"https://doi.org/10.1109/ICDL.2017.8124687","url":null,"abstract":"The deionized water dielectric is widely used as the cooling medium of the inner cooling system for HV converter valves. Theoretically, the electrolytic current in the cooling water is considered as one of the predominant causes of the corrosion of the aluminum heat sinks. The distribution of the electrolytic current inside the heat sink is revealed by simulating calculation. Corrosion tests with aluminum flake samples in simulated field conditions were conducted. The simulation results show that the electric field distortion around the grading electrode is the leading cause of the electrolytic current through the heat sink. The electrolytic current up to 10.82 μA are mainly collected by the 3.7-mm-wide area near the water inlet/outlet of the heat sink. Corrosion tests indicate that the electrolytic current has aggravated the corrosion of the heat sink in different ways. In the presence of anodic current, pit corrosion is observed due to stray-current corrosion. Whereas when cathodic current conducts through the heat sink, general corrosion occurs as a result of the aggregation of hydroxide ion. Further calculation reveals that over 95 percent of the anodic electrolytic current has contributed to the stray-current corrosion of the heat sink.","PeriodicalId":439228,"journal":{"name":"2017 IEEE 19th International Conference on Dielectric Liquids (ICDL)","volume":"323 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121900937","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 : 2017-06-01DOI: 10.1109/ICDL.2017.8124717
M. Spohner
This paper deals with the analysis of perspective and environmentally-friendly electrical insulating liquids for electrical engineering. Dielectric properties were measured using the high-resolution Novocontrol Alpha-A Frequency Analyzer in the frequency range 1 Hz–1 MHz in the temperature interval 243 K–363 K. The lowest value of dielectric constant of non-inhibited mineral oil (2.22) was exhibited at 363 K by Mogul Trafo N. Methyl oleate, an oil component which is usually present in large quantities, exhibited the value of dielectric constant equal to 3.23. MCT oil (oil contains triglycerides of medium chain) exhibited the value of dielectric constant equal to 3.93.
本文对电气工程中应用前景和环境友好型电绝缘液体进行了分析。使用高分辨率的Novocontrol Alpha-A频率分析仪在1 Hz-1 MHz频率范围内，在243 K - 363 K温度区间内测量介电性能。非抑制矿物油的介电常数在363 K时最低，为2.22。油酸甲酯是一种通常大量存在的油组分，其介电常数为3.23。MCT油(含中链甘油三酯的油)介电常数为3.93。
{"title":"Study of dielectric properties of mineral oils and natural oils and methyl esters of natural oils","authors":"M. Spohner","doi":"10.1109/ICDL.2017.8124717","DOIUrl":"https://doi.org/10.1109/ICDL.2017.8124717","url":null,"abstract":"This paper deals with the analysis of perspective and environmentally-friendly electrical insulating liquids for electrical engineering. Dielectric properties were measured using the high-resolution Novocontrol Alpha-A Frequency Analyzer in the frequency range 1 Hz–1 MHz in the temperature interval 243 K–363 K. The lowest value of dielectric constant of non-inhibited mineral oil (2.22) was exhibited at 363 K by Mogul Trafo N. Methyl oleate, an oil component which is usually present in large quantities, exhibited the value of dielectric constant equal to 3.23. MCT oil (oil contains triglycerides of medium chain) exhibited the value of dielectric constant equal to 3.93.","PeriodicalId":439228,"journal":{"name":"2017 IEEE 19th International Conference on Dielectric Liquids (ICDL)","volume":"336 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124720037","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 : 2017-06-01DOI: 10.1109/ICDL.2017.8124666
Jierui Zhou, M. Ren, M. Dong, Chongxing Zhang, Wenguang Huang, Yang Li
Oil impregnated paper is an important solid insulation dielectric in power transformers. Thus it is very significant to understand the dielectric properties of the oil impregnated paper. In this paper, a conductivity measuring system was built to explore the conduction mechanism of oil impregnated paper. This measuring system is able to measure the conduction current in the samples. Based on the system, the mathematical relationship between conduction current and field strength was studied firstly. The results show that the conduction current in oil impregnated paper is mainly caused by electrons injected from the electrodes. The Schottky coefficient ßs was calculated both in theoretical and experimental methods, and both results are in good agreement. The reasons for deviation between two results are analysed. The conduction current of aged oil impregnated papers were measured as a function of different electrical fields. The results show that with the increase of aging time, the conductivity of oil impregnated paper increases and the permittivity decreases.
{"title":"Electrical conduction of aged oil impregnated paper","authors":"Jierui Zhou, M. Ren, M. Dong, Chongxing Zhang, Wenguang Huang, Yang Li","doi":"10.1109/ICDL.2017.8124666","DOIUrl":"https://doi.org/10.1109/ICDL.2017.8124666","url":null,"abstract":"Oil impregnated paper is an important solid insulation dielectric in power transformers. Thus it is very significant to understand the dielectric properties of the oil impregnated paper. In this paper, a conductivity measuring system was built to explore the conduction mechanism of oil impregnated paper. This measuring system is able to measure the conduction current in the samples. Based on the system, the mathematical relationship between conduction current and field strength was studied firstly. The results show that the conduction current in oil impregnated paper is mainly caused by electrons injected from the electrodes. The Schottky coefficient ßs was calculated both in theoretical and experimental methods, and both results are in good agreement. The reasons for deviation between two results are analysed. The conduction current of aged oil impregnated papers were measured as a function of different electrical fields. The results show that with the increase of aging time, the conductivity of oil impregnated paper increases and the permittivity decreases.","PeriodicalId":439228,"journal":{"name":"2017 IEEE 19th International Conference on Dielectric Liquids (ICDL)","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124811696","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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