Pub Date : 2020-07-05DOI: 10.1109/ICD46958.2020.9341977
Xin Zhao, Siyi Zhang, Cheng-lu Lin, Zhi Yang, Zhonglei Li, T. Han
Cross-linked polyethylene (XLPE) plays a significant role in AC power cables. In the cables, the difference in temperatures of conductor and surrounding environment produces a temperature gradient in XLPE, and the electrical and thermal aging accelerate the degradation. When defects exist in the dielectric, an electrical tree may be initiated. Hence, it is necessary to research the electrical tree in XLPE under the temperature gradient. In this paper, XLPE samples were tested under 50 Hz AC voltage with multiple temperature gradients, and the electrical tree was recorded by a digital microscope. To simulate an electrical stress concentration, a pair of needle-plate electrodes was utilized in this experiment. There are two types of temperature gradients in this experiment, one is to set the needle electrode temperature to 100 °C and increase the ground electrode temperature from 30 to 70 °C, and the other is the opposite. The tree structure, growth process, fractal dimension, accumulated damage and tree length were recorded and analyzed. The experiment results indicate that the temperature gradient affects the growth rate and the structure of trees. When the ground electrode temperature is higher than the needle tip, the tree grows faster. The fractal dimension and the accumulated damage increase as the temperature gradient increases.
{"title":"Characterization of Electrical Treeing in XLPE versus Temperature Gradients","authors":"Xin Zhao, Siyi Zhang, Cheng-lu Lin, Zhi Yang, Zhonglei Li, T. Han","doi":"10.1109/ICD46958.2020.9341977","DOIUrl":"https://doi.org/10.1109/ICD46958.2020.9341977","url":null,"abstract":"Cross-linked polyethylene (XLPE) plays a significant role in AC power cables. In the cables, the difference in temperatures of conductor and surrounding environment produces a temperature gradient in XLPE, and the electrical and thermal aging accelerate the degradation. When defects exist in the dielectric, an electrical tree may be initiated. Hence, it is necessary to research the electrical tree in XLPE under the temperature gradient. In this paper, XLPE samples were tested under 50 Hz AC voltage with multiple temperature gradients, and the electrical tree was recorded by a digital microscope. To simulate an electrical stress concentration, a pair of needle-plate electrodes was utilized in this experiment. There are two types of temperature gradients in this experiment, one is to set the needle electrode temperature to 100 °C and increase the ground electrode temperature from 30 to 70 °C, and the other is the opposite. The tree structure, growth process, fractal dimension, accumulated damage and tree length were recorded and analyzed. The experiment results indicate that the temperature gradient affects the growth rate and the structure of trees. When the ground electrode temperature is higher than the needle tip, the tree grows faster. The fractal dimension and the accumulated damage increase as the temperature gradient increases.","PeriodicalId":6795,"journal":{"name":"2020 IEEE 3rd International Conference on Dielectrics (ICD)","volume":"23 1","pages":"25-28"},"PeriodicalIF":0.0,"publicationDate":"2020-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78032953","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 : 2020-07-05DOI: 10.1109/ICD46958.2020.9341890
K. Lahti, I. Rytöluoto, Minna Niittymäki, Eetta Saarimäki, M. Paajanen
In this paper a route from laboratory scale samples to full industrial scale production of biaxially oriented silica-PP nanocomposite capacitor films is for the first time shown and verified. Morphological and dielectric characteristics of laboratory scale produced and by full industrial tenter -process produced nanocomposite and neat-PP reference films are presented and compared. In addition to the short-term characteristics also ageing performance of the industrial films are studied. The results show closely comparative dielectric behavior of the films and thus verifies the successful up-scaling of the used nanocomposite recipe. Although certain amount of impurities and voids were observed in both nanocomposite films the low probability dielectric breakdown strength characteristics were considered promising. Modified trap distribution, decreased conductivity and improved dielectric loss behavior has been verified for the nanocomposite film while areas of further development are also recognized.
{"title":"From Laboratory to Industrial Scale: Comparison of Short- and Long-Term Dielectric Performance of Silica-Polypropylene Capacitor Films","authors":"K. Lahti, I. Rytöluoto, Minna Niittymäki, Eetta Saarimäki, M. Paajanen","doi":"10.1109/ICD46958.2020.9341890","DOIUrl":"https://doi.org/10.1109/ICD46958.2020.9341890","url":null,"abstract":"In this paper a route from laboratory scale samples to full industrial scale production of biaxially oriented silica-PP nanocomposite capacitor films is for the first time shown and verified. Morphological and dielectric characteristics of laboratory scale produced and by full industrial tenter -process produced nanocomposite and neat-PP reference films are presented and compared. In addition to the short-term characteristics also ageing performance of the industrial films are studied. The results show closely comparative dielectric behavior of the films and thus verifies the successful up-scaling of the used nanocomposite recipe. Although certain amount of impurities and voids were observed in both nanocomposite films the low probability dielectric breakdown strength characteristics were considered promising. Modified trap distribution, decreased conductivity and improved dielectric loss behavior has been verified for the nanocomposite film while areas of further development are also recognized.","PeriodicalId":6795,"journal":{"name":"2020 IEEE 3rd International Conference on Dielectrics (ICD)","volume":"80 1","pages":"661-664"},"PeriodicalIF":0.0,"publicationDate":"2020-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82304986","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 : 2020-07-05DOI: 10.1109/ICD46958.2020.9342021
E. Matić, M. Meissner, S. Schober, M. Mittelbach
Insulation liquids perform a vital role in protecting power equipment, such as transformers, from thermal, electrical and environmental stress. Considering the poor fire-safety properties and low biodegradability of mineral oil as the leading kind of insulation liquid, alternative insulation liquids are of high interest for their implementation in power equipment. In this experiment we aimed to simulate the processes occurring in faulty power equipment by ageing four different kinds of insulation liquids (mineral oil, GTL-insulation liquid, synthetic ester and natural ester) under laboratory conditions. The use of optimized analytical routine methods has allowed us to monitor as well as quantify volatile acid and polymer formations upon ageing of insulation liquids. The ageing process under aerated conditions has led to the formation of formic, acetic and propionic acid, especially in natural ester, alongside notable polymerization effects. All other types of insulation liquids showed significantly lower amounts of volatile acids. Per contra, the experiments conducted under oxygen-free conditions resulted in minimal volatile acid and polymer build-ups in all four insulation liquids.
{"title":"Volatile Acid and Polymer Formation in Various Insulation Liquids Upon Accelerated Thermal Ageing","authors":"E. Matić, M. Meissner, S. Schober, M. Mittelbach","doi":"10.1109/ICD46958.2020.9342021","DOIUrl":"https://doi.org/10.1109/ICD46958.2020.9342021","url":null,"abstract":"Insulation liquids perform a vital role in protecting power equipment, such as transformers, from thermal, electrical and environmental stress. Considering the poor fire-safety properties and low biodegradability of mineral oil as the leading kind of insulation liquid, alternative insulation liquids are of high interest for their implementation in power equipment. In this experiment we aimed to simulate the processes occurring in faulty power equipment by ageing four different kinds of insulation liquids (mineral oil, GTL-insulation liquid, synthetic ester and natural ester) under laboratory conditions. The use of optimized analytical routine methods has allowed us to monitor as well as quantify volatile acid and polymer formations upon ageing of insulation liquids. The ageing process under aerated conditions has led to the formation of formic, acetic and propionic acid, especially in natural ester, alongside notable polymerization effects. All other types of insulation liquids showed significantly lower amounts of volatile acids. Per contra, the experiments conducted under oxygen-free conditions resulted in minimal volatile acid and polymer build-ups in all four insulation liquids.","PeriodicalId":6795,"journal":{"name":"2020 IEEE 3rd International Conference on Dielectrics (ICD)","volume":"49 1","pages":"317-320"},"PeriodicalIF":0.0,"publicationDate":"2020-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80719830","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 : 2020-07-05DOI: 10.1109/ICD46958.2020.9341858
B. Adam, S. Tenbohlen, M. Beltle
Partial discharges are one of the main reasons of insulation failure in transformers. Multiple partial discharge sources in HV equipment can be active at the same time. Diagnosis is complicated by superimposed or overlapping patterns in the PRPD patterns. In order to classify the fault source correctly, the patterns must be separated first. In this paper we propose a method to separate partial discharge signals from different sources by their impulse waveform. A feature-set is constructed by selecting relevant features from a pool of 700 identified possible features. Then, different sources are separated by clustering techniques. Centroid-based clustering methods like the k-means algorithm are compared to density-based approaches like DBSCAN. After clustering multiple PRPD patterns can be calculated – one for each source. This method is developed on artificial partial discharge data, measured in the laboratory. Four different typical defect types are considered. Through multiple case studies we show, that the separation process works on different kinds of PD problems. This method works for all kinds of PD faults. It is shown, that PD sources not present in the training data used for development can also be separated reliably.
{"title":"Separation of superimposed PRPD Patterns by Signal Clustering","authors":"B. Adam, S. Tenbohlen, M. Beltle","doi":"10.1109/ICD46958.2020.9341858","DOIUrl":"https://doi.org/10.1109/ICD46958.2020.9341858","url":null,"abstract":"Partial discharges are one of the main reasons of insulation failure in transformers. Multiple partial discharge sources in HV equipment can be active at the same time. Diagnosis is complicated by superimposed or overlapping patterns in the PRPD patterns. In order to classify the fault source correctly, the patterns must be separated first. In this paper we propose a method to separate partial discharge signals from different sources by their impulse waveform. A feature-set is constructed by selecting relevant features from a pool of 700 identified possible features. Then, different sources are separated by clustering techniques. Centroid-based clustering methods like the k-means algorithm are compared to density-based approaches like DBSCAN. After clustering multiple PRPD patterns can be calculated – one for each source. This method is developed on artificial partial discharge data, measured in the laboratory. Four different typical defect types are considered. Through multiple case studies we show, that the separation process works on different kinds of PD problems. This method works for all kinds of PD faults. It is shown, that PD sources not present in the training data used for development can also be separated reliably.","PeriodicalId":6795,"journal":{"name":"2020 IEEE 3rd International Conference on Dielectrics (ICD)","volume":"96 1","pages":"858-861"},"PeriodicalIF":0.0,"publicationDate":"2020-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80359020","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 : 2020-07-05DOI: 10.1109/ICD46958.2020.9341815
R. Metz, M. Hassanzadeh
The effect of resistive field grading coatings on the electric field distribution in a medium voltage bushing has been studied. A typical coating is obtained by applying a commercial resistive field grading material and a conductive varnish that we both have previously electrically characterized. The electric field distribution over the bushing surface was computed and analyzed using a finite element method software (Flux 2D). The electric field enhancements at its critical points with and without field grading material were considered and confronted with experimental partial discharge detection. The complementary between the field grading material and the conductive varnish is highlighted: a special care of the true capability of the conductive layer to withdraw the electrical charges is stressed out.
{"title":"Benefit of Nonlinear Resistive Field Grading Materials on Medium Voltage Bushing by Finite Element Modeling (Flux 2D) vs Experimental Partial Discharge Measurements","authors":"R. Metz, M. Hassanzadeh","doi":"10.1109/ICD46958.2020.9341815","DOIUrl":"https://doi.org/10.1109/ICD46958.2020.9341815","url":null,"abstract":"The effect of resistive field grading coatings on the electric field distribution in a medium voltage bushing has been studied. A typical coating is obtained by applying a commercial resistive field grading material and a conductive varnish that we both have previously electrically characterized. The electric field distribution over the bushing surface was computed and analyzed using a finite element method software (Flux 2D). The electric field enhancements at its critical points with and without field grading material were considered and confronted with experimental partial discharge detection. The complementary between the field grading material and the conductive varnish is highlighted: a special care of the true capability of the conductive layer to withdraw the electrical charges is stressed out.","PeriodicalId":6795,"journal":{"name":"2020 IEEE 3rd International Conference on Dielectrics (ICD)","volume":"50 1","pages":"305-308"},"PeriodicalIF":0.0,"publicationDate":"2020-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79046984","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 : 2020-07-05DOI: 10.1109/ICD46958.2020.9341966
Hucheng Liang, B. Du, Jin Li, R. Zhao, Zehua Wang, Miaomiao Zhang, Ang Li, Q. Du
To reduce the electric field (E-field) distortion in a gassolid insulating system, a centrifugation technique is proposed to fabricate the interfacial E-field regulating (IER) insulator. During the curing process of the liquid epoxy/SiC mixture in the mold, a centrifugal force was used to force the SiC particles to the insulator surface, forming a uniform thin surface layer of nonlinear conductivity. After fabrication, electrical evaluations, including numerical simulations and flashover tests, were conducted to verify the E-field regulating effect of the novel insulator. As the thickness of the nonlinear-conductivity layer increases, the maximum E-field in the flashover region of the novel insulator declines and converges to a stable value, but the surface conduction loss continues growing. The flashover voltages of the novel insulator are improved by ~13% and ~21% under positive and negative voltages, respectively. By applying such novel insulators, a higher reliability and compacter structure can be realized for the DC-GIL.
{"title":"Interfacial E-field Regulating Insulator for DC Gas-solid Insulating System","authors":"Hucheng Liang, B. Du, Jin Li, R. Zhao, Zehua Wang, Miaomiao Zhang, Ang Li, Q. Du","doi":"10.1109/ICD46958.2020.9341966","DOIUrl":"https://doi.org/10.1109/ICD46958.2020.9341966","url":null,"abstract":"To reduce the electric field (E-field) distortion in a gassolid insulating system, a centrifugation technique is proposed to fabricate the interfacial E-field regulating (IER) insulator. During the curing process of the liquid epoxy/SiC mixture in the mold, a centrifugal force was used to force the SiC particles to the insulator surface, forming a uniform thin surface layer of nonlinear conductivity. After fabrication, electrical evaluations, including numerical simulations and flashover tests, were conducted to verify the E-field regulating effect of the novel insulator. As the thickness of the nonlinear-conductivity layer increases, the maximum E-field in the flashover region of the novel insulator declines and converges to a stable value, but the surface conduction loss continues growing. The flashover voltages of the novel insulator are improved by ~13% and ~21% under positive and negative voltages, respectively. By applying such novel insulators, a higher reliability and compacter structure can be realized for the DC-GIL.","PeriodicalId":6795,"journal":{"name":"2020 IEEE 3rd International Conference on Dielectrics (ICD)","volume":"268 1","pages":"297-300"},"PeriodicalIF":0.0,"publicationDate":"2020-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77970907","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 : 2020-07-05DOI: 10.1109/ICD46958.2020.9341921
P. Seri, G. Montanari
Designing insulation systems for DC application is not straightforward as under AC, both because electric field can distribute inside the insulation in significantly different ways, and due to the effect on field distribution of voltage transients, such as energizations and the polarity inversions. During and after each voltage variation, the electric field in the insulation is mainly driven by permittivity, as in AC, while at steady-state the electric field profile depends on conductivity and, hence, on dielectric material and load. This can impact on aging phenomena and rate, thus on the electro-thermal life of an insulation system. It is, therefore, important to estimate how long it takes for the electric field to reach its steady state condition (i.e. the transient time) upon voltage-time variations. Different methods for estimating the electric field transient time are discussed in this paper, from conductivity and permittivity measurements at high or low fields, as a function of temperature, to partial discharge time evolution. Specimens made by polymeric materials having different conductivities, and containing artificial defects, are used for the experimental validation of those methods.
{"title":"Modelling the electric field transients in DC insulation systems upon energization and voltage polarity inversion","authors":"P. Seri, G. Montanari","doi":"10.1109/ICD46958.2020.9341921","DOIUrl":"https://doi.org/10.1109/ICD46958.2020.9341921","url":null,"abstract":"Designing insulation systems for DC application is not straightforward as under AC, both because electric field can distribute inside the insulation in significantly different ways, and due to the effect on field distribution of voltage transients, such as energizations and the polarity inversions. During and after each voltage variation, the electric field in the insulation is mainly driven by permittivity, as in AC, while at steady-state the electric field profile depends on conductivity and, hence, on dielectric material and load. This can impact on aging phenomena and rate, thus on the electro-thermal life of an insulation system. It is, therefore, important to estimate how long it takes for the electric field to reach its steady state condition (i.e. the transient time) upon voltage-time variations. Different methods for estimating the electric field transient time are discussed in this paper, from conductivity and permittivity measurements at high or low fields, as a function of temperature, to partial discharge time evolution. Specimens made by polymeric materials having different conductivities, and containing artificial defects, are used for the experimental validation of those methods.","PeriodicalId":6795,"journal":{"name":"2020 IEEE 3rd International Conference on Dielectrics (ICD)","volume":"770 Pt A 1","pages":"485-488"},"PeriodicalIF":0.0,"publicationDate":"2020-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77050146","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 : 2020-07-05DOI: 10.1109/ICD46958.2020.9341867
B. Du, J. Xing, M. Xiao, Jin Li, R. Xu, Z. Ran, H. Liu, H.L. Sun
Ferroelectric polymer P(VDF-TrFE-CFE) is widely employed as energy storage materials of dielectric capacitors, but the discharge energy density of P(VDF-TrFE-CFE) is limited by the lower breakdown strength, which restricts the further development. The paper proposes a solution by preparing P(VDF-TrFE-CFE) composites based on bilayer structure and nanoparticles. Polyimide (PI) with high breakdown strength is used as the bottom layer, and the BaTiO3/Ferroelectric polymer composites BT-P(VDF-TrFE-CFE) with high dielectric constant is used as the top layer, the bilayer composite films PI/BTP(VDF-TrFE-CFE) doped with different content of BaTiO3 (1 vol.%, 3 vol.%, 5 vol.%) were prepared via coating, heat treatment and quenching. The microstructure and energy storage performance of bilayer films were analyzed, the results show that the discharge energy density of composite film doping with 3 vol.% of BaTiO3 can be up to 9.8 J/cm3 at 440 kV/mm, which is higher than pure P(VDF-TrFE-CFE) film (7.2 J/cm3). The energy storage efficiency of composite film is 46% at 440 kV/mm, slightly lower than pure P(VDF-TrFE-CFE) film (49% at 337 kV/mm).
{"title":"Bilayer PI/BaTiO3-P(VDF-TrFE-CFE) composites with high discharge energy density","authors":"B. Du, J. Xing, M. Xiao, Jin Li, R. Xu, Z. Ran, H. Liu, H.L. Sun","doi":"10.1109/ICD46958.2020.9341867","DOIUrl":"https://doi.org/10.1109/ICD46958.2020.9341867","url":null,"abstract":"Ferroelectric polymer P(VDF-TrFE-CFE) is widely employed as energy storage materials of dielectric capacitors, but the discharge energy density of P(VDF-TrFE-CFE) is limited by the lower breakdown strength, which restricts the further development. The paper proposes a solution by preparing P(VDF-TrFE-CFE) composites based on bilayer structure and nanoparticles. Polyimide (PI) with high breakdown strength is used as the bottom layer, and the BaTiO3/Ferroelectric polymer composites BT-P(VDF-TrFE-CFE) with high dielectric constant is used as the top layer, the bilayer composite films PI/BTP(VDF-TrFE-CFE) doped with different content of BaTiO3 (1 vol.%, 3 vol.%, 5 vol.%) were prepared via coating, heat treatment and quenching. The microstructure and energy storage performance of bilayer films were analyzed, the results show that the discharge energy density of composite film doping with 3 vol.% of BaTiO3 can be up to 9.8 J/cm3 at 440 kV/mm, which is higher than pure P(VDF-TrFE-CFE) film (7.2 J/cm3). The energy storage efficiency of composite film is 46% at 440 kV/mm, slightly lower than pure P(VDF-TrFE-CFE) film (49% at 337 kV/mm).","PeriodicalId":6795,"journal":{"name":"2020 IEEE 3rd International Conference on Dielectrics (ICD)","volume":"206 1","pages":"185-188"},"PeriodicalIF":0.0,"publicationDate":"2020-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77060536","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 : 2020-07-05DOI: 10.1109/ICD46958.2020.9342014
B.A. Orton, S. Cottrell, F. Pratt, S. Dodd, N. Chalashkanov
The development of a new technique using implanted 100% spin polarized positive muons to probe the behaviour of charge carriers within dielectrics is described. Muons are a well-established method for probing materials at the atomic level. They offer a local probe sensitive both to bound molecular charges and to free charge carriers in materials. A muon study to investigate the charge distribution within a composite dielectric - consisting of epoxy, mica and glass fibre components- as a function of the externally applied electric field strength (E-field) is reported. Implanted muons react with the host epoxy molecule, undergo chemical addition at specific locations and probe the local electronic structure. Muon spectra are interpreted through a comparison with the electronic structure calculated using Density Functional Theory.It is shown that the application of an external E-field modifies the form of the observed spectra. It is believed that the effect of an E-field on identified bound charges within the molecule is being observed, suggesting muons are an excellent probe for understanding local charge redistributions in polymeric dielectrics.
{"title":"Investigating the Electronic Properties of a Composite Dielectric under an Applied Electric Field by Muon Spectroscopy","authors":"B.A. Orton, S. Cottrell, F. Pratt, S. Dodd, N. Chalashkanov","doi":"10.1109/ICD46958.2020.9342014","DOIUrl":"https://doi.org/10.1109/ICD46958.2020.9342014","url":null,"abstract":"The development of a new technique using implanted 100% spin polarized positive muons to probe the behaviour of charge carriers within dielectrics is described. Muons are a well-established method for probing materials at the atomic level. They offer a local probe sensitive both to bound molecular charges and to free charge carriers in materials. A muon study to investigate the charge distribution within a composite dielectric - consisting of epoxy, mica and glass fibre components- as a function of the externally applied electric field strength (E-field) is reported. Implanted muons react with the host epoxy molecule, undergo chemical addition at specific locations and probe the local electronic structure. Muon spectra are interpreted through a comparison with the electronic structure calculated using Density Functional Theory.It is shown that the application of an external E-field modifies the form of the observed spectra. It is believed that the effect of an E-field on identified bound charges within the molecule is being observed, suggesting muons are an excellent probe for understanding local charge redistributions in polymeric dielectrics.","PeriodicalId":6795,"journal":{"name":"2020 IEEE 3rd International Conference on Dielectrics (ICD)","volume":"64 1","pages":"562-565"},"PeriodicalIF":0.0,"publicationDate":"2020-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75549321","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}
At present, the oil-paper insulation structure is mainly composed of traditional mineral oil and cellulose insulation paper. The hots pot of future research is to select better insulation oil to improve the overall insulation life of the system. Compared with traditional mineral insulation oil, gas to liquid(GTL) oil made from base oil refined by natural gas liquefaction technology by Fischer-Tropsch(FT) method are characterized by high oxidative stability and low sulfur content. In this paper, the space charge accumulation, distribution and attenuation characteristics of oil-impregnated paper composed of GTL oil and traditional mineral oil were studied. The space trap energy level and trap density distribution of two oil-impregnated papers were obtained according to isothermal decay current(IDC) method. The experimental results show that in the voltage-on stage, traditional mineral oil-impregnated paper is more prone to charge injection and the injection speed is faster. In the voltage-off stage, the traditional mineral oil-impregnated paper attenuates the charge faster, and the GTL oil-impregnated paper has more residual charge. Moreover, the trap level of GTL oil-impregnated paper is deeper than that of traditional mineral oil-impregnated paper.
{"title":"Effect of Insulating Oil on Space Charge Characteristics of Oil-impregnated Paper Under DC Voltage","authors":"Ganlin Mao, Shengtao Li, Shijun Li, Zhao Ge, Liuqing Yang, Liuhao Jiang","doi":"10.1109/ICD46958.2020.9341880","DOIUrl":"https://doi.org/10.1109/ICD46958.2020.9341880","url":null,"abstract":"At present, the oil-paper insulation structure is mainly composed of traditional mineral oil and cellulose insulation paper. The hots pot of future research is to select better insulation oil to improve the overall insulation life of the system. Compared with traditional mineral insulation oil, gas to liquid(GTL) oil made from base oil refined by natural gas liquefaction technology by Fischer-Tropsch(FT) method are characterized by high oxidative stability and low sulfur content. In this paper, the space charge accumulation, distribution and attenuation characteristics of oil-impregnated paper composed of GTL oil and traditional mineral oil were studied. The space trap energy level and trap density distribution of two oil-impregnated papers were obtained according to isothermal decay current(IDC) method. The experimental results show that in the voltage-on stage, traditional mineral oil-impregnated paper is more prone to charge injection and the injection speed is faster. In the voltage-off stage, the traditional mineral oil-impregnated paper attenuates the charge faster, and the GTL oil-impregnated paper has more residual charge. Moreover, the trap level of GTL oil-impregnated paper is deeper than that of traditional mineral oil-impregnated paper.","PeriodicalId":6795,"journal":{"name":"2020 IEEE 3rd International Conference on Dielectrics (ICD)","volume":"51 1","pages":"443-446"},"PeriodicalIF":0.0,"publicationDate":"2020-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75709243","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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