Pub Date : 2021-12-12DOI: 10.1109/CEIDP50766.2021.9705362
S. Kumara, T. Hammarström, Xiangdong Xu, A. M. Pourrahimi, Christian Müller, Y. Serdyuk
This study aims at understanding electrical treeing in XLPE due to DC short circuits. A wire-plane type test object has been excited by a series of short circuit events after applying DC voltages of different levels and duration. The development of thin filamentary trees and their morphology was correlated with the inception probability. It was observed that the latter as well as the length of the trees increased with the magnitude of the applied voltage and the number of short circuit events. These observations are in good agreement with the hypothesis that the release of stored energy during short circuit causes electromechanical stresses in the materials giving rise to treeing process analogous to mechanical crack formation. It is suggested that the application of an adequate number of short circuits at a suitable voltage level and a sufficient stress duration can be used as a DC treeing test procedure.
{"title":"DC Electrical Trees in XLPE Induced by Short Circuits","authors":"S. Kumara, T. Hammarström, Xiangdong Xu, A. M. Pourrahimi, Christian Müller, Y. Serdyuk","doi":"10.1109/CEIDP50766.2021.9705362","DOIUrl":"https://doi.org/10.1109/CEIDP50766.2021.9705362","url":null,"abstract":"This study aims at understanding electrical treeing in XLPE due to DC short circuits. A wire-plane type test object has been excited by a series of short circuit events after applying DC voltages of different levels and duration. The development of thin filamentary trees and their morphology was correlated with the inception probability. It was observed that the latter as well as the length of the trees increased with the magnitude of the applied voltage and the number of short circuit events. These observations are in good agreement with the hypothesis that the release of stored energy during short circuit causes electromechanical stresses in the materials giving rise to treeing process analogous to mechanical crack formation. It is suggested that the application of an adequate number of short circuits at a suitable voltage level and a sufficient stress duration can be used as a DC treeing test procedure.","PeriodicalId":6837,"journal":{"name":"2021 IEEE Conference on Electrical Insulation and Dielectric Phenomena (CEIDP)","volume":"38 1","pages":"275-278"},"PeriodicalIF":0.0,"publicationDate":"2021-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73225205","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 : 2021-12-12DOI: 10.1109/CEIDP50766.2021.9705353
O. G. Gnonhoue, A. Velazquez-Salazar, I. Preda, É. David
The presence of defects in the insulating wall of high voltage capacitors can cause early deterioration of the insulating system and can lead to the degradation of electrical properties. The presence of partial discharges (PD) is considered to be one of the main causes of initiation of the degradation of the insulating wall. Accordingly, PD measurement is used as a non-destructive control test in order to assess the quality of a high voltage capacitor. It permits to ensure that the capacitors are free from defects and, in case PD are measured, it can help identifying the types of defects. In this context, the main objective of this work is the identification of Phase-Resolved Partial Discharge (PRPD) patterns and their correlation with the type of defect introduced in the dielectric wall of all-film capacitors impregnated with a thermosetting resin.
{"title":"Measurement and Analysis of partial discharges patterns in high voltage resin impregnated capacitors","authors":"O. G. Gnonhoue, A. Velazquez-Salazar, I. Preda, É. David","doi":"10.1109/CEIDP50766.2021.9705353","DOIUrl":"https://doi.org/10.1109/CEIDP50766.2021.9705353","url":null,"abstract":"The presence of defects in the insulating wall of high voltage capacitors can cause early deterioration of the insulating system and can lead to the degradation of electrical properties. The presence of partial discharges (PD) is considered to be one of the main causes of initiation of the degradation of the insulating wall. Accordingly, PD measurement is used as a non-destructive control test in order to assess the quality of a high voltage capacitor. It permits to ensure that the capacitors are free from defects and, in case PD are measured, it can help identifying the types of defects. In this context, the main objective of this work is the identification of Phase-Resolved Partial Discharge (PRPD) patterns and their correlation with the type of defect introduced in the dielectric wall of all-film capacitors impregnated with a thermosetting resin.","PeriodicalId":6837,"journal":{"name":"2021 IEEE Conference on Electrical Insulation and Dielectric Phenomena (CEIDP)","volume":"9 1","pages":"295-298"},"PeriodicalIF":0.0,"publicationDate":"2021-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75530603","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 : 2021-12-12DOI: 10.1109/CEIDP50766.2021.9705454
Zhuolin Cheng, Yiwei Long, Kangning Wu, Chuang Zhang, Hang Fu, Shihang Wang, Jianying Li, Shenghe Wang
Direct bonding copper (DBC) substrate is employed in high power density modules, improving its reliability is of critical significance for the safety of power electronic system. In this paper, thermal cycling ageing from -55°C to 150°C was conducted on alumina DBC substrate. Both the variation of interface structures and dielectric properties were obtained in the failure process. Based on the experimental results, the substrate damaged at ~70 cycles due to the thermal expansion coefficient (CTE) mismatch between copper and ceramic. After 45 cycles, copper/ceramic interface turned rougher. Equivalent capacitance (Ceq) was found to be almost unchanged at ~115.8 pF. While tanδ increased from 6.2×10−4 to 1.3×10−3 since the initiation of micro cracks. Afterwards, dramatic drop of Ceq and tanδ was noticed, with Ceq decreased from 115.8 pF to 83.0 pF and tanδ declined to 4.5×10−4. Besides, cliff shaped structure was found around the crack point. It is convinced that, propagation of micro cracks broadened the air gap between copper and ceramic, finally diminished the Ceq. Obviously, the turning point of Ceq is an important indicator in thermal cycling fatigue. Dielectric measurement might be an effective non-destructive technique for condition assessment of DBC substrate.
{"title":"A Non-destructive Condition Assessment Method for DBC Substrate: Dielectric Measurement","authors":"Zhuolin Cheng, Yiwei Long, Kangning Wu, Chuang Zhang, Hang Fu, Shihang Wang, Jianying Li, Shenghe Wang","doi":"10.1109/CEIDP50766.2021.9705454","DOIUrl":"https://doi.org/10.1109/CEIDP50766.2021.9705454","url":null,"abstract":"Direct bonding copper (DBC) substrate is employed in high power density modules, improving its reliability is of critical significance for the safety of power electronic system. In this paper, thermal cycling ageing from -55°C to 150°C was conducted on alumina DBC substrate. Both the variation of interface structures and dielectric properties were obtained in the failure process. Based on the experimental results, the substrate damaged at ~70 cycles due to the thermal expansion coefficient (CTE) mismatch between copper and ceramic. After 45 cycles, copper/ceramic interface turned rougher. Equivalent capacitance (Ceq) was found to be almost unchanged at ~115.8 pF. While tanδ increased from 6.2×10−4 to 1.3×10−3 since the initiation of micro cracks. Afterwards, dramatic drop of Ceq and tanδ was noticed, with Ceq decreased from 115.8 pF to 83.0 pF and tanδ declined to 4.5×10−4. Besides, cliff shaped structure was found around the crack point. It is convinced that, propagation of micro cracks broadened the air gap between copper and ceramic, finally diminished the Ceq. Obviously, the turning point of Ceq is an important indicator in thermal cycling fatigue. Dielectric measurement might be an effective non-destructive technique for condition assessment of DBC substrate.","PeriodicalId":6837,"journal":{"name":"2021 IEEE Conference on Electrical Insulation and Dielectric Phenomena (CEIDP)","volume":"2016 1","pages":"522-525"},"PeriodicalIF":0.0,"publicationDate":"2021-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73405542","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 : 2021-12-12DOI: 10.1109/CEIDP50766.2021.9705345
L. Briano, A. Bruzzone, F. Gallesi, F. Guastavino, E. Torello
- Low voltage rotating electrical machines are usually characterized by organic enameled wires windings that can not be subjected to the Partial Discharge (PD) activity since it acts an organic material erosion until the total failure of the electrical equipment. Moreover, to have a good control of the speed and torque of the electric motor, usually they are fed by power electronic drives that generates voltage waveforms with lots of harmonic distortion and fast rise and fall times such as PWM power supply. With sinusoidal voltage waveforms, the PD measure can give useful information about the defect of the device under test. It can be interesting to investigate if it is possible to analyze the PD pattern shape even when the voltage waveform power supply has fast rise and fall time fronts. The purpose of this research work is to acquire the PD pattern with an ad hoc measurement system to study the shape of these graphs even when in the case of fast rise and fall time fronts.
{"title":"PD Pattern Analysis Relevant to PWM-like Voltage Waveforms","authors":"L. Briano, A. Bruzzone, F. Gallesi, F. Guastavino, E. Torello","doi":"10.1109/CEIDP50766.2021.9705345","DOIUrl":"https://doi.org/10.1109/CEIDP50766.2021.9705345","url":null,"abstract":"- Low voltage rotating electrical machines are usually characterized by organic enameled wires windings that can not be subjected to the Partial Discharge (PD) activity since it acts an organic material erosion until the total failure of the electrical equipment. Moreover, to have a good control of the speed and torque of the electric motor, usually they are fed by power electronic drives that generates voltage waveforms with lots of harmonic distortion and fast rise and fall times such as PWM power supply. With sinusoidal voltage waveforms, the PD measure can give useful information about the defect of the device under test. It can be interesting to investigate if it is possible to analyze the PD pattern shape even when the voltage waveform power supply has fast rise and fall time fronts. The purpose of this research work is to acquire the PD pattern with an ad hoc measurement system to study the shape of these graphs even when in the case of fast rise and fall time fronts.","PeriodicalId":6837,"journal":{"name":"2021 IEEE Conference on Electrical Insulation and Dielectric Phenomena (CEIDP)","volume":"75 1","pages":"299-302"},"PeriodicalIF":0.0,"publicationDate":"2021-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82358338","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 : 2021-12-12DOI: 10.1109/CEIDP50766.2021.9705450
C. Nieves, R. Wilke, S. Bishop, M. Lanagan, P. Clem
Electrical conduction in silica-based capacitors under a combined effect of intermediate electric field and temperature (2.5 – 10 kV/mm, 50-300°C) is dominated by localized motion of high mobility ions such as sodium. Thermally stimulated polarization and depolarization current (TSPC/TSDC) characterization was carried out on poled fused silica and AF32 glass samples. Two relaxation mechanisms were found during the depolarization step and an anomalous response for the second TSDC peak was observed. Absorption current measurements were performed on the glass samples and a time-dependent response was observed when subjected to different electro-thermal conditions. It was found that at low temperature (T = 175 °C) and short times, the current follows a linear behavior (I α V) while at high temperature (T = 250 °C), the current follows V0.5. TSPC/TSDC and absorption current measurements results led to the conclusion that (1) Poole-Frenkel dominates conduction at high temperatures and at longer times and that (2) ionic blockage and/or H+/H3O+ injection are responsible for the observed anomalous current response.
{"title":"Electrical conduction and polarization of silica-based capacitors under electro-thermal poling","authors":"C. Nieves, R. Wilke, S. Bishop, M. Lanagan, P. Clem","doi":"10.1109/CEIDP50766.2021.9705450","DOIUrl":"https://doi.org/10.1109/CEIDP50766.2021.9705450","url":null,"abstract":"Electrical conduction in silica-based capacitors under a combined effect of intermediate electric field and temperature (2.5 – 10 kV/mm, 50-300°C) is dominated by localized motion of high mobility ions such as sodium. Thermally stimulated polarization and depolarization current (TSPC/TSDC) characterization was carried out on poled fused silica and AF32 glass samples. Two relaxation mechanisms were found during the depolarization step and an anomalous response for the second TSDC peak was observed. Absorption current measurements were performed on the glass samples and a time-dependent response was observed when subjected to different electro-thermal conditions. It was found that at low temperature (T = 175 °C) and short times, the current follows a linear behavior (I α V) while at high temperature (T = 250 °C), the current follows V0.5. TSPC/TSDC and absorption current measurements results led to the conclusion that (1) Poole-Frenkel dominates conduction at high temperatures and at longer times and that (2) ionic blockage and/or H+/H3O+ injection are responsible for the observed anomalous current response.","PeriodicalId":6837,"journal":{"name":"2021 IEEE Conference on Electrical Insulation and Dielectric Phenomena (CEIDP)","volume":"11 1","pages":"171-174"},"PeriodicalIF":0.0,"publicationDate":"2021-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82396129","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 : 2021-12-12DOI: 10.1109/CEIDP50766.2021.9705372
Takaaki Matsuki, Y. Inoue, K. Hamasuna, M. Kozako, M. Hikita, Naoki Fukumoto, N. Kamei
Dicyclopentadiene (DCP) resin is a hydrocarbon-based thermosetting resin (HTR) with better crack resistance than epoxy (EP) resin, as an organic insulating material used in low-temperature regions such as liquid helium (LHe) and liquid nitrogen (LN2). This paper presents dielectric breakdown strength, Eb, of DCP under AC and standard lightning impulse (Imp) voltage application at room temperature and LN2 temperature while comparing with results of EP resin. It was found that Eb of DCP at LN2 temperature exceeded that at room temperature, indicating ∂Eb∂/T < 0, and larger than that of EP. Experimental results showed that Eb of EP and DCP at room temperature decreased with increasing the sample thickness d, indicating ∂Eb∂/d < 0. Since EP exhibited ∂Eb∂/T < 0 and ∂Eb/∂d < 0, an attempt is made to discuss breakdown mechanism in terms of the electron avalanche breakdown theory as a dominant one in EP. As a result, the ionization coefficient H of EP was evaluated as 1670 kV/mm, the mean free path λ as 195 nm, and the mobility μ as 65.4×10-4 m2/Vs. On the other hand, since DCP shows a negative temperature dependence (∂Eb/∂T < 0) in the low temperature region, the breakdown mechanism is discussed with the electronic thermal breakdown mechanism proposed by Frohlich based on the balance between the energy gain due to the interaction between electrons in the excited impurity level (ΔV) and electrons in the conduction band, and the energy loss to the lattice system. As a result, ΔV was evaluated to be 5.7 meV in DCP.
{"title":"Characteristics of Breakdown Strength of Hydrocarbon Thermosetting Resin in Low Temperature Environment","authors":"Takaaki Matsuki, Y. Inoue, K. Hamasuna, M. Kozako, M. Hikita, Naoki Fukumoto, N. Kamei","doi":"10.1109/CEIDP50766.2021.9705372","DOIUrl":"https://doi.org/10.1109/CEIDP50766.2021.9705372","url":null,"abstract":"Dicyclopentadiene (DCP) resin is a hydrocarbon-based thermosetting resin (HTR) with better crack resistance than epoxy (EP) resin, as an organic insulating material used in low-temperature regions such as liquid helium (LHe) and liquid nitrogen (LN2). This paper presents dielectric breakdown strength, Eb, of DCP under AC and standard lightning impulse (Imp) voltage application at room temperature and LN2 temperature while comparing with results of EP resin. It was found that Eb of DCP at LN2 temperature exceeded that at room temperature, indicating ∂Eb∂/T < 0, and larger than that of EP. Experimental results showed that Eb of EP and DCP at room temperature decreased with increasing the sample thickness d, indicating ∂Eb∂/d < 0. Since EP exhibited ∂Eb∂/T < 0 and ∂Eb/∂d < 0, an attempt is made to discuss breakdown mechanism in terms of the electron avalanche breakdown theory as a dominant one in EP. As a result, the ionization coefficient H of EP was evaluated as 1670 kV/mm, the mean free path λ as 195 nm, and the mobility μ as 65.4×10-4 m2/Vs. On the other hand, since DCP shows a negative temperature dependence (∂Eb/∂T < 0) in the low temperature region, the breakdown mechanism is discussed with the electronic thermal breakdown mechanism proposed by Frohlich based on the balance between the energy gain due to the interaction between electrons in the excited impurity level (ΔV) and electrons in the conduction band, and the energy loss to the lattice system. As a result, ΔV was evaluated to be 5.7 meV in DCP.","PeriodicalId":6837,"journal":{"name":"2021 IEEE Conference on Electrical Insulation and Dielectric Phenomena (CEIDP)","volume":"24 1","pages":"578-581"},"PeriodicalIF":0.0,"publicationDate":"2021-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91044528","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 : 2021-12-12DOI: 10.1109/CEIDP50766.2021.9705339
Pablo Donoso, R. Schurch, J. Ardila-Rey
Electrical treeing is one of the main degradation mechanisms in high voltage polymeric insulation that could lead to electrical equipment failure. Electrical trees grow under partial discharge (PD) activity; therefore, PD measurement is a fundamental tool for electrical insulation diagnosis. In this paper, PDs are analyzed for electrical trees grown in epoxy resin needle-plane samples at very low frequency (VLF) 0.1 Hz and 50 Hz excitation voltages. PD analysis was carried out through the traditional PRPD analysis and with nonlinear time series analysis (NLTSA) tools, which is more recent in this context. For PRPD analysis at VLF, the discharge power and the 95th percentile of PD amplitude showed a nearly linear increase with the tree length. However, at 50 Hz, these parameters showed an oscillatory behavior which could be a consequence of a more conductive structure. For NLTSA, we calculated the correlation dimension and Lyapunov exponent. This last parameter showed positive values for VLF and 50 Hz tests, indicating a deterministic chaotic behavior for both cases.
{"title":"Partial discharges in electrical trees grown at 0.1 (VLF) and 50 Hz analyzed using PRPD and NLTSA","authors":"Pablo Donoso, R. Schurch, J. Ardila-Rey","doi":"10.1109/CEIDP50766.2021.9705339","DOIUrl":"https://doi.org/10.1109/CEIDP50766.2021.9705339","url":null,"abstract":"Electrical treeing is one of the main degradation mechanisms in high voltage polymeric insulation that could lead to electrical equipment failure. Electrical trees grow under partial discharge (PD) activity; therefore, PD measurement is a fundamental tool for electrical insulation diagnosis. In this paper, PDs are analyzed for electrical trees grown in epoxy resin needle-plane samples at very low frequency (VLF) 0.1 Hz and 50 Hz excitation voltages. PD analysis was carried out through the traditional PRPD analysis and with nonlinear time series analysis (NLTSA) tools, which is more recent in this context. For PRPD analysis at VLF, the discharge power and the 95th percentile of PD amplitude showed a nearly linear increase with the tree length. However, at 50 Hz, these parameters showed an oscillatory behavior which could be a consequence of a more conductive structure. For NLTSA, we calculated the correlation dimension and Lyapunov exponent. This last parameter showed positive values for VLF and 50 Hz tests, indicating a deterministic chaotic behavior for both cases.","PeriodicalId":6837,"journal":{"name":"2021 IEEE Conference on Electrical Insulation and Dielectric Phenomena (CEIDP)","volume":"2 1","pages":"200-203"},"PeriodicalIF":0.0,"publicationDate":"2021-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86300417","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 : 2021-12-12DOI: 10.1109/CEIDP50766.2021.9705315
F. Liu, S. Rowland, V. Peesapati, H. Zheng
Electrical tree initiation and growth in low-density polyethylene (LDPE) with a needle-plane geometry under negative DC fields was investigated in this work. Many differences have been found between the cases of the needle being energized positive (positive DC fields) and those in which the needle is negative (negative DC fields). Tree initiation in the latter could occur under a wider range of voltage magnitudes and had a shorter initiation length. Negative trees also tended to initiate more quickly than positive trees, and considerable length propagation was observed to immediately follow the initiation. Furthermore, there were differences in partial discharge signals between the two polarities. These distinctions are thought to be caused by the differences in nature between hole injection and electron injection and the subsequent space charge accumulation in the polymer around the needle tip.
{"title":"Electrical Tree Initiation and Growth in LDPE Under Negative DC Fields","authors":"F. Liu, S. Rowland, V. Peesapati, H. Zheng","doi":"10.1109/CEIDP50766.2021.9705315","DOIUrl":"https://doi.org/10.1109/CEIDP50766.2021.9705315","url":null,"abstract":"Electrical tree initiation and growth in low-density polyethylene (LDPE) with a needle-plane geometry under negative DC fields was investigated in this work. Many differences have been found between the cases of the needle being energized positive (positive DC fields) and those in which the needle is negative (negative DC fields). Tree initiation in the latter could occur under a wider range of voltage magnitudes and had a shorter initiation length. Negative trees also tended to initiate more quickly than positive trees, and considerable length propagation was observed to immediately follow the initiation. Furthermore, there were differences in partial discharge signals between the two polarities. These distinctions are thought to be caused by the differences in nature between hole injection and electron injection and the subsequent space charge accumulation in the polymer around the needle tip.","PeriodicalId":6837,"journal":{"name":"2021 IEEE Conference on Electrical Insulation and Dielectric Phenomena (CEIDP)","volume":"1652 1","pages":"355-358"},"PeriodicalIF":0.0,"publicationDate":"2021-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86513298","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 : 2021-12-12DOI: 10.1109/CEIDP50766.2021.9705334
S. Rohith, Niharika Baruah, S. K. Nayak
Liquid insulation is employed in transformers along with the solid insulation for the reliable operation. The transformer insulation has technologically advanced over time and a number of varieties are explored. Every insulation is found to have some or the other advantages and disadvantages. The application of a particular liquid insulation is chosen based on its properties. Among the insulating oils being studied for transformer application, nanofluids are delivering promising electrical and thermal characteristics compared to the base oils. The dielectric frequency response is one of the non-destructive and offline technique to analyze a few dielectric properties of the insulating oil and it is used to estimate the moisture content of pressboard and the conductivity of the insulating oils, unlike the power frequency test which can only be used for estimating the contaminants. The frequency response is observed over a wide range of frequencies. The low frequency response is very much crucial in characterizing the dipole moment as it is significant at lower frequencies. In this paper, the concentration of the insulating nanoparticle in base oil is varied and the frequency response, polarization, and conductivity are studied at room temperature. The response is a depiction of the condition of the liquid insulation. The conductivity, relative permittivity and the dissipation factor are plotted. All these parameters are in the frequency range from 1 mHz to 10 kHz, which is the suitable range to study the liquid insulation.
{"title":"Influence of Concentration of Nanoparticles on the Dielectric Frequency Response of an Insulating Nanofluid","authors":"S. Rohith, Niharika Baruah, S. K. Nayak","doi":"10.1109/CEIDP50766.2021.9705334","DOIUrl":"https://doi.org/10.1109/CEIDP50766.2021.9705334","url":null,"abstract":"Liquid insulation is employed in transformers along with the solid insulation for the reliable operation. The transformer insulation has technologically advanced over time and a number of varieties are explored. Every insulation is found to have some or the other advantages and disadvantages. The application of a particular liquid insulation is chosen based on its properties. Among the insulating oils being studied for transformer application, nanofluids are delivering promising electrical and thermal characteristics compared to the base oils. The dielectric frequency response is one of the non-destructive and offline technique to analyze a few dielectric properties of the insulating oil and it is used to estimate the moisture content of pressboard and the conductivity of the insulating oils, unlike the power frequency test which can only be used for estimating the contaminants. The frequency response is observed over a wide range of frequencies. The low frequency response is very much crucial in characterizing the dipole moment as it is significant at lower frequencies. In this paper, the concentration of the insulating nanoparticle in base oil is varied and the frequency response, polarization, and conductivity are studied at room temperature. The response is a depiction of the condition of the liquid insulation. The conductivity, relative permittivity and the dissipation factor are plotted. All these parameters are in the frequency range from 1 mHz to 10 kHz, which is the suitable range to study the liquid insulation.","PeriodicalId":6837,"journal":{"name":"2021 IEEE Conference on Electrical Insulation and Dielectric Phenomena (CEIDP)","volume":"34 1","pages":"418-421"},"PeriodicalIF":0.0,"publicationDate":"2021-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82734549","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 : 2021-12-12DOI: 10.1109/CEIDP50766.2021.9705386
M. Jebli, T. Martiré, J. Laurentie, P. Notingher, L. Boyer, J. Castellon
This paper presents space charge measurement technique for dc cables. The principle of the method is measuring a current representative of space charge after applying a thermal step in the cable insulation. For long cables, thermal step method allows the measurement of space charge by perturbing the electrostatic balance using Joule effect in the conductor. The thermal conduction into insulation causes a locally and temporarily modification of electric properties and the circulation of displacement current between the core and outer screen. This paper presents procedure for sizing the power pulse needed to apply the thermal step method. Experimental results obtained using mini-cable confirm space charge measurements in a non-intrusive manner.
{"title":"Non-intrusive technique for measuring space charges in dc cables","authors":"M. Jebli, T. Martiré, J. Laurentie, P. Notingher, L. Boyer, J. Castellon","doi":"10.1109/CEIDP50766.2021.9705386","DOIUrl":"https://doi.org/10.1109/CEIDP50766.2021.9705386","url":null,"abstract":"This paper presents space charge measurement technique for dc cables. The principle of the method is measuring a current representative of space charge after applying a thermal step in the cable insulation. For long cables, thermal step method allows the measurement of space charge by perturbing the electrostatic balance using Joule effect in the conductor. The thermal conduction into insulation causes a locally and temporarily modification of electric properties and the circulation of displacement current between the core and outer screen. This paper presents procedure for sizing the power pulse needed to apply the thermal step method. Experimental results obtained using mini-cable confirm space charge measurements in a non-intrusive manner.","PeriodicalId":6837,"journal":{"name":"2021 IEEE Conference on Electrical Insulation and Dielectric Phenomena (CEIDP)","volume":"8 1","pages":"13-16"},"PeriodicalIF":0.0,"publicationDate":"2021-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86036203","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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