Pub Date : 2019-06-01DOI: 10.1109/ICDL.2019.8796815
Randy Cox
This paper describes the traditional interpretation of the CO CO2/CO ratio as it relates to dissolved gas analysis and what new research has revealed about the ratio in recent years. The industry at large has considered this ratio as a single number, for diagnostic purposes, at a given point in time. New information suggests that this is likely not the most beneficial position to take. Traditionally the ratio has been used as an indicator of the thermal decomposition of cellulose. More recent research of this topic has revealed that this ratio may even predict the deterioration of cellulose prior to any thermal acceleration.
{"title":"The History and Significance of the Carbon Oxide Ratio","authors":"Randy Cox","doi":"10.1109/ICDL.2019.8796815","DOIUrl":"https://doi.org/10.1109/ICDL.2019.8796815","url":null,"abstract":"This paper describes the traditional interpretation of the CO CO2/CO ratio as it relates to dissolved gas analysis and what new research has revealed about the ratio in recent years. The industry at large has considered this ratio as a single number, for diagnostic purposes, at a given point in time. New information suggests that this is likely not the most beneficial position to take. Traditionally the ratio has been used as an indicator of the thermal decomposition of cellulose. More recent research of this topic has revealed that this ratio may even predict the deterioration of cellulose prior to any thermal acceleration.","PeriodicalId":102217,"journal":{"name":"2019 IEEE 20th International Conference on Dielectric Liquids (ICDL)","volume":"31 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":"127841361","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}
In the development of on-line monitoring technique for transformer aging status, detecting concentration of methanol dissolved in transformer oil by the method of surface enhanced Raman spectroscopy (SERS) is a novel and promising technique. By use of Raman spectroscopy technique, we can improve various shortcomings of traditional detection technology. In this paper, the concentration of methanol dissolved in 2 mL/L methanol-oil solution was effectively detected by surface enhanced Raman spectroscopy. In the first, Raman spectra of single methanol molecule and its SERS were simulated to analyze the Raman peaks of methanol. A SERS substrate was prepared with selective enhancement. Based on prepared SERS substrate, concentration of methanol dissolved in transformer oil with content of 2 mL/L have been effectively detected. This helped us to further study the lower concentration of methanol in oil and make quantitative analysis.
{"title":"A SERS Substrate For Detecting Methanol In Transformer Oil","authors":"Shuhua Zhang, Weigen Chen, Fu Wan, Haiyang Shi, Weiran Zhou, Jiayi Zhang, Chengzhi Zhu","doi":"10.1109/ICDL.2019.8796557","DOIUrl":"https://doi.org/10.1109/ICDL.2019.8796557","url":null,"abstract":"In the development of on-line monitoring technique for transformer aging status, detecting concentration of methanol dissolved in transformer oil by the method of surface enhanced Raman spectroscopy (SERS) is a novel and promising technique. By use of Raman spectroscopy technique, we can improve various shortcomings of traditional detection technology. In this paper, the concentration of methanol dissolved in 2 mL/L methanol-oil solution was effectively detected by surface enhanced Raman spectroscopy. In the first, Raman spectra of single methanol molecule and its SERS were simulated to analyze the Raman peaks of methanol. A SERS substrate was prepared with selective enhancement. Based on prepared SERS substrate, concentration of methanol dissolved in transformer oil with content of 2 mL/L have been effectively detected. This helped us to further study the lower concentration of methanol in oil and make quantitative analysis.","PeriodicalId":102217,"journal":{"name":"2019 IEEE 20th International Conference on Dielectric Liquids (ICDL)","volume":"21 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":"132273216","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.2019.8796834
P. Livesey, M. Lashbrook, Russell Martin
Traditionally, mineral oil has been used as the insulating liquid in transformers due to its high electrical breakdown strength and cooling ability. More recently, natural and synthetic ester based dielectric liquids are increasingly adopted as alternatives, offering much improved fire safety and environmental protection. The dielectric dissipation factor (DDF), via tan delta measurement, has traditionally been used as one of the key metrics for quality evaluation of unused transformer mineral oils. Understanding the chemical differences between esters and mineral oil and which factors affect material properties such as ester DDF is rapidly becoming of greater importance. By monitoring the individual effects of increased ambient temperature and UV exposure on the DDF of synthetic and natural esters, this investigation aims to provide data which can be used to refine interpretation of dielectric dissipation factor for esters. The overall condition of high DDF esters, and the implications this could have for a transformer, are also evaluated to allow conclusions to be drawn on the relevance of a DDF limit in ester standards.
{"title":"Investigation of the factors affecting the dielectric dissipation factor of synthetic and natural esters","authors":"P. Livesey, M. Lashbrook, Russell Martin","doi":"10.1109/ICDL.2019.8796834","DOIUrl":"https://doi.org/10.1109/ICDL.2019.8796834","url":null,"abstract":"Traditionally, mineral oil has been used as the insulating liquid in transformers due to its high electrical breakdown strength and cooling ability. More recently, natural and synthetic ester based dielectric liquids are increasingly adopted as alternatives, offering much improved fire safety and environmental protection. The dielectric dissipation factor (DDF), via tan delta measurement, has traditionally been used as one of the key metrics for quality evaluation of unused transformer mineral oils. Understanding the chemical differences between esters and mineral oil and which factors affect material properties such as ester DDF is rapidly becoming of greater importance. By monitoring the individual effects of increased ambient temperature and UV exposure on the DDF of synthetic and natural esters, this investigation aims to provide data which can be used to refine interpretation of dielectric dissipation factor for esters. The overall condition of high DDF esters, and the implications this could have for a transformer, are also evaluated to allow conclusions to be drawn on the relevance of a DDF limit in ester standards.","PeriodicalId":102217,"journal":{"name":"2019 IEEE 20th International Conference on Dielectric Liquids (ICDL)","volume":"25 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":"134568861","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}
Oil-immersed inverted current transformer, as an important electrical equipment in power grid, is mainly used in power plants and substations. Accidents caused by oil-immersed inverted current transformers are generally accompanied by explosions, which not only reduce the amount of electricity delivered, but also damage other nearby equipment in the substation and even cause casualties. Therefore, it is very necessary to detect and evaluate the operation status of oil-immersed inverted current transformer and study the fault prevention technology to reduce the probability of accidents. According to the common faults of oil-immersed inverted current transformer, this paper firstly analyzed the parts and components with high fault rate of current transformer. Combined with the operating condition of current transformer and its internal insulation structure, the internal temperature field simulation model of current transformer and the temperature calculation model of key parts were established. It was found that the temperature near the winding of the oil-immersed inverted current transformer was the highest, while the temperature rise at the lower part far from the heat source was very small. The simulation results were basically consistent with the experimental results, and it was found that the temperature distribution on both sides of the primary conductor in the head region of the current transformer was symmetrical.
{"title":"Study on temperature distribution in oil-immersed inverted current transformer","authors":"Xiaoping Yang, Yiming Wu, Jiansheng Li, Chao Wei, Shengquan Wang, Leifeng Huang, Bonan Li, Youyuan Wang","doi":"10.1109/ICDL.2019.8796597","DOIUrl":"https://doi.org/10.1109/ICDL.2019.8796597","url":null,"abstract":"Oil-immersed inverted current transformer, as an important electrical equipment in power grid, is mainly used in power plants and substations. Accidents caused by oil-immersed inverted current transformers are generally accompanied by explosions, which not only reduce the amount of electricity delivered, but also damage other nearby equipment in the substation and even cause casualties. Therefore, it is very necessary to detect and evaluate the operation status of oil-immersed inverted current transformer and study the fault prevention technology to reduce the probability of accidents. According to the common faults of oil-immersed inverted current transformer, this paper firstly analyzed the parts and components with high fault rate of current transformer. Combined with the operating condition of current transformer and its internal insulation structure, the internal temperature field simulation model of current transformer and the temperature calculation model of key parts were established. It was found that the temperature near the winding of the oil-immersed inverted current transformer was the highest, while the temperature rise at the lower part far from the heat source was very small. The simulation results were basically consistent with the experimental results, and it was found that the temperature distribution on both sides of the primary conductor in the head region of the current transformer was symmetrical.","PeriodicalId":102217,"journal":{"name":"2019 IEEE 20th International Conference on Dielectric Liquids (ICDL)","volume":"363 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":"124565696","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.2019.8796591
D. Putintsev, N. M. Putintsev
In the work, we present the new method for calculation dielectric properties for Water in the wide temperature range. We use the modified Onsager-Kirkwood-Fröhlich theory, which makes it possible to calculate the polarization characteristics without using the static permittivity. We assumed that the dielectric is an isotropic medium consisting of molecules that do not interact with each other and are located in molecular electric fields. It allows us to use the average cosine of the angle between local electric field vectors and the dipole moment vectors of molecules in a medium as the average measure of the local orientation of the dipoles. This approach also makes it possible to equate the value of the energy of the interaction of dipoles with molecular fields to the value of the internal interaction energy if the energy of the interaction of the dipoles with external fields used for the experimental determination of the value of static permittivity is much less than the energy of the interaction. The calculated values of the dipole moment agree with the modern quantum mechanical calculations, and the results of calculating the values of permittivity are in practical agreement with experiment in the wide range of123.15K-573.15K. The method allows to calculate the static permittivity of water in various aggregate states: ice Ih in the range from 123K to melting point, supercooled water in the range from 238K to melting point, water at the saturation line from the melting point to the precritical region.
在工作中，我们提出了计算水在宽温度范围内介电特性的新方法。我们使用了修正的Onsager-Kirkwood-Fröhlich理论，使得在不使用静态介电常数的情况下计算极化特性成为可能。我们假设电介质是一种各向同性介质，由互不相互作用的分子组成，并且位于分子电场中。它允许我们使用局部电场矢量和介质中分子偶极矩矢量之间夹角的平均余弦值作为偶极子局部取向的平均度量。如果用于测定静态介电常数值的实验用的偶极子与外场的相互作用的能量远小于相互作用的能量，那么这种方法也使偶极子与分子场相互作用的能量等于内部相互作用能的值成为可能。偶极矩的计算值与现代量子力学计算结果一致，介电常数的计算结果在123.15 k -573.15 k范围内与实验结果基本一致。该方法可以计算水在各种聚集状态下的静态介电常数:冰Ih在123K到熔点范围内，过冷水在238K到熔点范围内，水在熔点到临界区域的饱和线上。
{"title":"The theoretical study of dielectric properties of water using the modified Onsager-Kirkwood-Fröhlich theory","authors":"D. Putintsev, N. M. Putintsev","doi":"10.1109/ICDL.2019.8796591","DOIUrl":"https://doi.org/10.1109/ICDL.2019.8796591","url":null,"abstract":"In the work, we present the new method for calculation dielectric properties for Water in the wide temperature range. We use the modified Onsager-Kirkwood-Fröhlich theory, which makes it possible to calculate the polarization characteristics without using the static permittivity. We assumed that the dielectric is an isotropic medium consisting of molecules that do not interact with each other and are located in molecular electric fields. It allows us to use the average cosine of the angle between local electric field vectors and the dipole moment vectors of molecules in a medium as the average measure of the local orientation of the dipoles. This approach also makes it possible to equate the value of the energy of the interaction of dipoles with molecular fields to the value of the internal interaction energy if the energy of the interaction of the dipoles with external fields used for the experimental determination of the value of static permittivity is much less than the energy of the interaction. The calculated values of the dipole moment agree with the modern quantum mechanical calculations, and the results of calculating the values of permittivity are in practical agreement with experiment in the wide range of123.15K-573.15K. The method allows to calculate the static permittivity of water in various aggregate states: ice Ih in the range from 123K to melting point, supercooled water in the range from 238K to melting point, water at the saturation line from the melting point to the precritical region.","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":"127986265","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.2019.8796729
J. Yagoobi
Pumping of single-phase liquid or two-phase liquid/vapor is encountered in a wide range of technological applications. Utilization of electro-hydro-dynamics (EHD) to induce fluid motion is known as an effective approach for situations where special requirements and restrictions are imposed, while enhanced heat and mass transfer are required. The implementation of the EHD phenomena to heat and mass transport introduces complex interactions among inter-dependent variables. The EHD pumping phenomena involve interaction of electric fields and flow fields in a dielectric fluid medium. This interaction induces the fluid motion through the presence of electric body force.In this paper, the fundamentals of EHD driven fluid flow are described. The evolution of EHD driven heat and mass transport technologies for space applications are presented. Specifically, the results of single-phase liquid and two-phase heat transport experiments that were conducted on board variable-gravity parabolic flights are provided. The EHD conduction pumping technology is expected to provide technological advances that will support various space missions.
{"title":"Transport of Heat and Mass with Electrical Field - from Earth to Space","authors":"J. Yagoobi","doi":"10.1109/ICDL.2019.8796729","DOIUrl":"https://doi.org/10.1109/ICDL.2019.8796729","url":null,"abstract":"Pumping of single-phase liquid or two-phase liquid/vapor is encountered in a wide range of technological applications. Utilization of electro-hydro-dynamics (EHD) to induce fluid motion is known as an effective approach for situations where special requirements and restrictions are imposed, while enhanced heat and mass transfer are required. The implementation of the EHD phenomena to heat and mass transport introduces complex interactions among inter-dependent variables. The EHD pumping phenomena involve interaction of electric fields and flow fields in a dielectric fluid medium. This interaction induces the fluid motion through the presence of electric body force.In this paper, the fundamentals of EHD driven fluid flow are described. The evolution of EHD driven heat and mass transport technologies for space applications are presented. Specifically, the results of single-phase liquid and two-phase heat transport experiments that were conducted on board variable-gravity parabolic flights are provided. The EHD conduction pumping technology is expected to provide technological advances that will support various space missions.","PeriodicalId":102217,"journal":{"name":"2019 IEEE 20th International Conference on Dielectric Liquids (ICDL)","volume":"10 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":"115480959","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.2019.8796699
M. Kuhnke, K. Homeier, P. Werle
The formation of solid wax-like ageing products in mineral oil under high voltage stress is known for almost a century. It was observed in oil-impregnated cables, bushings and capacitors. Its formation was generally attributed to high field strength and partial discharges. Since these types of equipment do not rely on oil flow for cooling the wax formation was seen as a sign of wear and not by itself as threat to the equipment.With the improvement of materials and design tools, the field strength in transformers increased. In recent years there was a significant number of outages in distribution transformers, which were related to partial discharges and wax formation. The purpose of this research is to understand how this wax is formed and how different insulation liquids behave in regard to the wax formation. Observations from the investigation of faulty transformers are compared to a lab experiment. A scaled model of the high voltage insulation of a distribution transformer was designed and build to investigate the influence of temperature and partial discharges on the generation of waxlike substances in the laboratory. Different insulation fluids, such as synthetic and natural esters and silicone fluids are investigated as well as a mineral oil for comparison. They are stressed with partial discharges for a duration of 200h. The partial discharges are monitored to allow a comparison between the PD energy and the amount of wax formed during the experiment. The tests are performed at different temperatures, as previous investigations have shown a significant influence of the temperature.
{"title":"Comparison of X-Wax Formation in Different Insulation Liquids","authors":"M. Kuhnke, K. Homeier, P. Werle","doi":"10.1109/ICDL.2019.8796699","DOIUrl":"https://doi.org/10.1109/ICDL.2019.8796699","url":null,"abstract":"The formation of solid wax-like ageing products in mineral oil under high voltage stress is known for almost a century. It was observed in oil-impregnated cables, bushings and capacitors. Its formation was generally attributed to high field strength and partial discharges. Since these types of equipment do not rely on oil flow for cooling the wax formation was seen as a sign of wear and not by itself as threat to the equipment.With the improvement of materials and design tools, the field strength in transformers increased. In recent years there was a significant number of outages in distribution transformers, which were related to partial discharges and wax formation. The purpose of this research is to understand how this wax is formed and how different insulation liquids behave in regard to the wax formation. Observations from the investigation of faulty transformers are compared to a lab experiment. A scaled model of the high voltage insulation of a distribution transformer was designed and build to investigate the influence of temperature and partial discharges on the generation of waxlike substances in the laboratory. Different insulation fluids, such as synthetic and natural esters and silicone fluids are investigated as well as a mineral oil for comparison. They are stressed with partial discharges for a duration of 200h. The partial discharges are monitored to allow a comparison between the PD energy and the amount of wax formed during the experiment. The tests are performed at different temperatures, as previous investigations have shown a significant influence of the temperature.","PeriodicalId":102217,"journal":{"name":"2019 IEEE 20th International Conference on Dielectric Liquids (ICDL)","volume":"5 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":"114356530","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.2019.8796562
D. Putintsev, N. M. Putintsev
The determination of the electronic polarizability of molecules is carried out by quantum-mechanical, refractometric and spectrometric methods. Refractometry is the simplest and most reliable method, since to determine the values of the electronic polarizability, it is required to have data on the absolute refractive index, substance density (molar volume) and the theoretical relation relating these parameters to electron polarizability. The Lorentz-Lorenz equation is currently used as such a relation. In this paper the justification of the new equation for determining the electronic component of the isotropic polarizability of molecules is given. From the experimental data on the density and absolute refractive index of a substance, the values of the average electronic polarizability of 62 different molecules were determined. The calculation was performed for the condensed state of a substance at 293.15K.
{"title":"New equation for calculating electronic polarizability using refractometry","authors":"D. Putintsev, N. M. Putintsev","doi":"10.1109/ICDL.2019.8796562","DOIUrl":"https://doi.org/10.1109/ICDL.2019.8796562","url":null,"abstract":"The determination of the electronic polarizability of molecules is carried out by quantum-mechanical, refractometric and spectrometric methods. Refractometry is the simplest and most reliable method, since to determine the values of the electronic polarizability, it is required to have data on the absolute refractive index, substance density (molar volume) and the theoretical relation relating these parameters to electron polarizability. The Lorentz-Lorenz equation is currently used as such a relation. In this paper the justification of the new equation for determining the electronic component of the isotropic polarizability of molecules is given. From the experimental data on the density and absolute refractive index of a substance, the values of the average electronic polarizability of 62 different molecules were determined. The calculation was performed for the condensed state of a substance at 293.15K.","PeriodicalId":102217,"journal":{"name":"2019 IEEE 20th International Conference on Dielectric Liquids (ICDL)","volume":"107 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":"127560071","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.2019.8796785
M. Meissner, Martin Darmann, S. Schober, M. Mittelbach, C. Sumereder
To determine the reliability of furan compound analysis for insulation-system health prediction, the furan level found in oil, paper and pressboard was monitored throughout a large-scale ageing study. Therefore, thermally upgraded and normal Kraft paper as well as transformer pressboard were immersed in 4 different types of insulation liquid (mineral oil, G-t-L oil, synthetic and natural ester) at 3 different ageing temperatures (110, 130 and $150^{circ}mathrm{C})$ and studied throughout a 56 day ageing setup, resulting in 100 mixed samples and 300 furan analyses. While the evolution of furan compounds in each system was somehow steady, comparisons between different material mixes and temperatures show significant aberrations. For similar stages of wear, standard deviations of 100% and more are detectable for the total furan compound concentration in oil, while deviations in solid insulation materials can be even higher. Due to the complexity and high number of variables, irregular analysis intervals without supporting information seem to be highly arguable for transformer health prediction.
{"title":"Reliability Study of Furan Level Analysis for Transformer Health Prediction","authors":"M. Meissner, Martin Darmann, S. Schober, M. Mittelbach, C. Sumereder","doi":"10.1109/ICDL.2019.8796785","DOIUrl":"https://doi.org/10.1109/ICDL.2019.8796785","url":null,"abstract":"To determine the reliability of furan compound analysis for insulation-system health prediction, the furan level found in oil, paper and pressboard was monitored throughout a large-scale ageing study. Therefore, thermally upgraded and normal Kraft paper as well as transformer pressboard were immersed in 4 different types of insulation liquid (mineral oil, G-t-L oil, synthetic and natural ester) at 3 different ageing temperatures (110, 130 and $150^{circ}mathrm{C})$ and studied throughout a 56 day ageing setup, resulting in 100 mixed samples and 300 furan analyses. While the evolution of furan compounds in each system was somehow steady, comparisons between different material mixes and temperatures show significant aberrations. For similar stages of wear, standard deviations of 100% and more are detectable for the total furan compound concentration in oil, while deviations in solid insulation materials can be even higher. Due to the complexity and high number of variables, irregular analysis intervals without supporting information seem to be highly arguable for transformer health prediction.","PeriodicalId":102217,"journal":{"name":"2019 IEEE 20th International Conference on Dielectric Liquids (ICDL)","volume":"2014 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":"128185087","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.2019.8796575
Ming Dong Xinyi, Xinyi Ma, Yang Li, Jiacheng Xie, M. Ren
Adding some nanoparticles to the transformer oil can improve its heat exchange properties as well as its dielectric withstanding characteristics, which has attract more and more attentions in the world. The conductance characteristics of transformer oil-based nanofluids (TNFs), especially at different temperatures, will help to understand the modification theory. The charge carrier transport processes at different electric fields can be divided into three stages: Ohmic, tunneling and space charge limited current (SCLC), respectively. In Ohmic stage at a very low field, the addition of nanoparticles increases the carrier number density, thus the conduction current is increased. In tunneling stage at medium to high electric field strengths, the main charge carriers in the transformer oil change from ions and colloidal particles to electrons emitted from the electrodes. The addition of nanoparticles increases the barrier thickness at the metal-liquid interface, which reduces the amount of electrons passing through the interface region. Therefore, the field strength required for electron transport is enhanced, and the dielectric strength is improved. In the space charge limited current stage at a very high electric field, the large trap density of TNFs lowers the carrier mobility, suppressing the discharge. In addition, as the temperature increases, the accelerated movement of the carriers increases the conduction current in the transformer oil. However, the electron tunneling process in the tunneling stage is little affected by the change in temperature.
{"title":"Investigation of Temperature Effect on Conductance Characteristics of Transformer Oil-based Nanofluids","authors":"Ming Dong Xinyi, Xinyi Ma, Yang Li, Jiacheng Xie, M. Ren","doi":"10.1109/ICDL.2019.8796575","DOIUrl":"https://doi.org/10.1109/ICDL.2019.8796575","url":null,"abstract":"Adding some nanoparticles to the transformer oil can improve its heat exchange properties as well as its dielectric withstanding characteristics, which has attract more and more attentions in the world. The conductance characteristics of transformer oil-based nanofluids (TNFs), especially at different temperatures, will help to understand the modification theory. The charge carrier transport processes at different electric fields can be divided into three stages: Ohmic, tunneling and space charge limited current (SCLC), respectively. In Ohmic stage at a very low field, the addition of nanoparticles increases the carrier number density, thus the conduction current is increased. In tunneling stage at medium to high electric field strengths, the main charge carriers in the transformer oil change from ions and colloidal particles to electrons emitted from the electrodes. The addition of nanoparticles increases the barrier thickness at the metal-liquid interface, which reduces the amount of electrons passing through the interface region. Therefore, the field strength required for electron transport is enhanced, and the dielectric strength is improved. In the space charge limited current stage at a very high electric field, the large trap density of TNFs lowers the carrier mobility, suppressing the discharge. In addition, as the temperature increases, the accelerated movement of the carriers increases the conduction current in the transformer oil. However, the electron tunneling process in the tunneling stage is little affected by the change in temperature.","PeriodicalId":102217,"journal":{"name":"2019 IEEE 20th International Conference on Dielectric Liquids (ICDL)","volume":"24 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":"126672853","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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