Pub Date : 2025-06-04DOI: 10.1109/TDEI.2025.3576326
Pujan Adhikari;Mona Ghassemi
Incorporating nonlinear resistive field grading materials (FGMs) onto metal-brazed substrates has been widely investigated as an efficient electric field reduction strategy at triple points (TPs) within ultrawide bandgap [(U)WBG] power modules. However, most investigations have been carried out using either dc or sinusoidal ac voltages despite actual (U)WBG power modules operating with high-frequency square voltages featuring high-slew rate (${textit {dv}}/ {textit {dt}}$ ). Thus, this study introduces a field-dependent conductivity (FDC) layer to analyze electric field reduction under high-frequency, high-slew-rate square voltages. Using COMSOL Multiphysics, both coated and uncoated structures were modeled to evaluate electric field reduction. When employing nonlinear FDC coating, the findings demonstrate a notable decrease in field stress, even under square voltages with rapid rise times and high frequencies. However, relying solely on the nonlinear FDC layer may not adequately address the electric field concerns, particularly when factoring in protrusions on metallization layers and reducing layer coverage. In response to this challenge, protrusions at the metal ends are incorporated into a protruding substrate configuration. This entire structure is then coated with a nonlinear FDC layer. The combined impact of the protruding substrate and nonlinear FDC layer effectively reduces the electric field. However, when the rise time is shortened to 75 ns and the frequency is raised to 500 kHz, the electric field stress around TPs exceeds the insulation’s withstand strength. This finding underscores the need for further research into alternative strategies as the prevalent strategies are unable to effectively mitigate electric fields in real-world operating conditions of (U)WBG power modules.
{"title":"Electric Field Mitigation in (U)WBG Power Module Using Nonlinear Field-Dependent Conductivity Layer and Protruding Substrate Under High-Frequency, High-Slew-Rate Square Wave Voltages","authors":"Pujan Adhikari;Mona Ghassemi","doi":"10.1109/TDEI.2025.3576326","DOIUrl":"https://doi.org/10.1109/TDEI.2025.3576326","url":null,"abstract":"Incorporating nonlinear resistive field grading materials (FGMs) onto metal-brazed substrates has been widely investigated as an efficient electric field reduction strategy at triple points (TPs) within ultrawide bandgap [(U)WBG] power modules. However, most investigations have been carried out using either dc or sinusoidal ac voltages despite actual (U)WBG power modules operating with high-frequency square voltages featuring high-slew rate (<inline-formula> <tex-math>${textit {dv}}/ {textit {dt}}$ </tex-math></inline-formula>). Thus, this study introduces a field-dependent conductivity (FDC) layer to analyze electric field reduction under high-frequency, high-slew-rate square voltages. Using COMSOL Multiphysics, both coated and uncoated structures were modeled to evaluate electric field reduction. When employing nonlinear FDC coating, the findings demonstrate a notable decrease in field stress, even under square voltages with rapid rise times and high frequencies. However, relying solely on the nonlinear FDC layer may not adequately address the electric field concerns, particularly when factoring in protrusions on metallization layers and reducing layer coverage. In response to this challenge, protrusions at the metal ends are incorporated into a protruding substrate configuration. This entire structure is then coated with a nonlinear FDC layer. The combined impact of the protruding substrate and nonlinear FDC layer effectively reduces the electric field. However, when the rise time is shortened to 75 ns and the frequency is raised to 500 kHz, the electric field stress around TPs exceeds the insulation’s withstand strength. This finding underscores the need for further research into alternative strategies as the prevalent strategies are unable to effectively mitigate electric fields in real-world operating conditions of (U)WBG power modules.","PeriodicalId":13247,"journal":{"name":"IEEE Transactions on Dielectrics and Electrical Insulation","volume":"32 5","pages":"3078-3088"},"PeriodicalIF":3.1,"publicationDate":"2025-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145210086","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-02DOI: 10.1109/TDEI.2025.3570211
{"title":"IEEE Transactions on Dielectrics and Electrical Insulation Information for Authors","authors":"","doi":"10.1109/TDEI.2025.3570211","DOIUrl":"https://doi.org/10.1109/TDEI.2025.3570211","url":null,"abstract":"","PeriodicalId":13247,"journal":{"name":"IEEE Transactions on Dielectrics and Electrical Insulation","volume":"32 3","pages":"C4-C4"},"PeriodicalIF":2.9,"publicationDate":"2025-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11021256","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144196886","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-02DOI: 10.1109/TDEI.2025.3570205
{"title":"IEEE Transactions on Dielectrics and Electrical Insulation Publication Information","authors":"","doi":"10.1109/TDEI.2025.3570205","DOIUrl":"https://doi.org/10.1109/TDEI.2025.3570205","url":null,"abstract":"","PeriodicalId":13247,"journal":{"name":"IEEE Transactions on Dielectrics and Electrical Insulation","volume":"32 3","pages":"C2-C2"},"PeriodicalIF":2.9,"publicationDate":"2025-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11021278","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144213597","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-02DOI: 10.1109/TDEI.2025.3570207
{"title":"IEEE Dielectrics and Electrical Insulation Society","authors":"","doi":"10.1109/TDEI.2025.3570207","DOIUrl":"https://doi.org/10.1109/TDEI.2025.3570207","url":null,"abstract":"","PeriodicalId":13247,"journal":{"name":"IEEE Transactions on Dielectrics and Electrical Insulation","volume":"32 3","pages":"C3-C3"},"PeriodicalIF":2.9,"publicationDate":"2025-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11021268","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144196744","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-02DOI: 10.1109/TDEI.2025.3574952
Lin Du;Xin Li;Hui Feng
The tangent value of the dielectric loss angle, tan$delta $ , is a crucial electrical parameter that indicates the insulation status of capacitive equipment. The accurate measurement of tan$delta $ is critical for detecting both overall defects and localized large defects in the insulation medium. The equipment voltage and its insulation leakage current serve as the electrical parameters for tan$delta $ calculation. This article examines the factors influencing online monitoring of voltage and current measurements, proposes an equivalent circuit model affecting voltage and current measurements, and conducts an error analysis of tan$delta $ . The study identifies current sensors, insulation of signal cable, spatial electromagnetic field coupling, cable parameters, and signal conditioning unit characteristics as the main factors affecting insulation leakage current measurements. Additionally, the insulation and temperature characteristics of capacitor units in capacitive voltage transformers (CVTs) are identified as the primary factors influencing voltage measurement. By establishing multifactor equivalent circuit models for current and voltage measurement channels, this article theoretically and experimentally analyzes the effects of various factors on tan$delta $ . This work not only provides a detailed explanation of the various sources of errors in online monitoring of the dielectric loss angle but also offers valuable theoretical guidance for the online measurement of tan$delta $ under complex operating conditions.
{"title":"Analysis of Online Monitoring Error and Equivalent Circuit Model for Dielectric Loss Angle of Capacitive Equipment","authors":"Lin Du;Xin Li;Hui Feng","doi":"10.1109/TDEI.2025.3574952","DOIUrl":"https://doi.org/10.1109/TDEI.2025.3574952","url":null,"abstract":"The tangent value of the dielectric loss angle, tan<inline-formula> <tex-math>$delta $ </tex-math></inline-formula>, is a crucial electrical parameter that indicates the insulation status of capacitive equipment. The accurate measurement of tan<inline-formula> <tex-math>$delta $ </tex-math></inline-formula> is critical for detecting both overall defects and localized large defects in the insulation medium. The equipment voltage and its insulation leakage current serve as the electrical parameters for tan<inline-formula> <tex-math>$delta $ </tex-math></inline-formula> calculation. This article examines the factors influencing online monitoring of voltage and current measurements, proposes an equivalent circuit model affecting voltage and current measurements, and conducts an error analysis of tan<inline-formula> <tex-math>$delta $ </tex-math></inline-formula>. The study identifies current sensors, insulation of signal cable, spatial electromagnetic field coupling, cable parameters, and signal conditioning unit characteristics as the main factors affecting insulation leakage current measurements. Additionally, the insulation and temperature characteristics of capacitor units in capacitive voltage transformers (CVTs) are identified as the primary factors influencing voltage measurement. By establishing multifactor equivalent circuit models for current and voltage measurement channels, this article theoretically and experimentally analyzes the effects of various factors on tan<inline-formula> <tex-math>$delta $ </tex-math></inline-formula>. This work not only provides a detailed explanation of the various sources of errors in online monitoring of the dielectric loss angle but also offers valuable theoretical guidance for the online measurement of tan<inline-formula> <tex-math>$delta $ </tex-math></inline-formula> under complex operating conditions.","PeriodicalId":13247,"journal":{"name":"IEEE Transactions on Dielectrics and Electrical Insulation","volume":"32 4","pages":"2143-2152"},"PeriodicalIF":3.1,"publicationDate":"2025-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144739960","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-28DOI: 10.1109/TDEI.2025.3564931
Yiwei Wang;Li Zhang;Bilal Iqbal Ayubi;Guowei Hou
High-frequency transformers play a crucial role in power electronic transformers for renewable energy systems, enabling compact designs and efficient energy conversion. However, under high-frequency electrical stress (10–40 kHz), their insulation systems face serious challenges such as excessive heating and intense partial discharges (PDs), potentially resulting in premature insulation failure. Currently, no unified international standard exists for high-frequency transformer insulation, and conventional power frequency tests fail to accurately reflect performance under high-frequency conditions. This study establishes a method for determining equivalent test voltages between power frequency and high frequency by conducting PD measurements and analyzing material dielectric strength equivalency. From these analyses, power frequency-high frequency conversion factors (p and ${p}1$ ) are derived, yielding recommended test voltages for high-frequency transformers. To capture the complexity of PD phenomena, innovative entropy-based features—both 1-D and 2-D [amplitude distribution entropy (ADE), circular distribution entropy (CDE), and 2D phase-ADE (2D-PADE)]—and multifractal spectrum (MFS) features [amplitude MFS (AMFS), phase MFS (PMFS), and amplitude PMFS (APMFS)] are comprehensively investigated at varying voltage amplitudes and frequencies. Notably, 2D-PADE and APMFS exhibit distinct trends under high-frequency conditions, reflecting the evolution from single-peak to multicluster discharge patterns. While 2D-PADE first rises and then declines—indicating changes in global distribution randomness—APMFS initially decreases and later increases, highlighting enhanced multiscale complexity at higher frequencies. These complementary indicators facilitate more precise characterization of PD mechanisms, enabling meaningful comparisons of power- and high-frequency discharge patterns. Practical tests on high-frequency transformer confirm the reliability and effectiveness of the proposed method. The findings furnish essential reference data and methodological guidance for factory insulation testing and condition assessment of high-frequency power equipment.
{"title":"Experimental Methods for Power Frequency–High-Frequency Equivalency Based on Dielectric Strength and Partial Discharge Characteristics of Insulation Materials","authors":"Yiwei Wang;Li Zhang;Bilal Iqbal Ayubi;Guowei Hou","doi":"10.1109/TDEI.2025.3564931","DOIUrl":"https://doi.org/10.1109/TDEI.2025.3564931","url":null,"abstract":"High-frequency transformers play a crucial role in power electronic transformers for renewable energy systems, enabling compact designs and efficient energy conversion. However, under high-frequency electrical stress (10–40 kHz), their insulation systems face serious challenges such as excessive heating and intense partial discharges (PDs), potentially resulting in premature insulation failure. Currently, no unified international standard exists for high-frequency transformer insulation, and conventional power frequency tests fail to accurately reflect performance under high-frequency conditions. This study establishes a method for determining equivalent test voltages between power frequency and high frequency by conducting PD measurements and analyzing material dielectric strength equivalency. From these analyses, power frequency-high frequency conversion factors (p and <inline-formula> <tex-math>${p}1$ </tex-math></inline-formula>) are derived, yielding recommended test voltages for high-frequency transformers. To capture the complexity of PD phenomena, innovative entropy-based features—both 1-D and 2-D [amplitude distribution entropy (ADE), circular distribution entropy (CDE), and 2D phase-ADE (2D-PADE)]—and multifractal spectrum (MFS) features [amplitude MFS (AMFS), phase MFS (PMFS), and amplitude PMFS (APMFS)] are comprehensively investigated at varying voltage amplitudes and frequencies. Notably, 2D-PADE and APMFS exhibit distinct trends under high-frequency conditions, reflecting the evolution from single-peak to multicluster discharge patterns. While 2D-PADE first rises and then declines—indicating changes in global distribution randomness—APMFS initially decreases and later increases, highlighting enhanced multiscale complexity at higher frequencies. These complementary indicators facilitate more precise characterization of PD mechanisms, enabling meaningful comparisons of power- and high-frequency discharge patterns. Practical tests on high-frequency transformer confirm the reliability and effectiveness of the proposed method. The findings furnish essential reference data and methodological guidance for factory insulation testing and condition assessment of high-frequency power equipment.","PeriodicalId":13247,"journal":{"name":"IEEE Transactions on Dielectrics and Electrical Insulation","volume":"33 1","pages":"769-779"},"PeriodicalIF":3.1,"publicationDate":"2025-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146102990","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-22DOI: 10.1109/TDEI.2025.3563165
Leena Gautam;T. V. Shraddha;R. Sarathi;I. Fofana;T. Jayasree;U. Mohan Rao
This study investigates the impact of Dibenzyl Disulfide (DBDS) on the aging and insulating properties of the pressboard used in transformer systems under varying ambient conditions. While DBDS acts as an antioxidant during the initial stages of aging, its thermal decomposition generates corrosive sulfur compounds that contribute to the chemical degradation of both the oil and pressboard insulation. These sulfur interactions in the transformer lead to the formation of copper sulfide (Cu2S), which subsequently diffuses into the pressboard, altering its thermal and electrical characteristics. Laser-induced breakdown spectroscopy (LIBS) is employed to confirm the presence of elemental copper and sulfur, indicating the Cu2S diffusion in the pressboard. The study correlates the heat trap density of the pressboard with the effects of DBDS and ambient gases on dielectric parameters. Heat trap density is identified as a critical parameter influencing the material’s electrical behavior, affecting charge storage and dissipation processes. Additionally, heat dissipation properties of the aged pressboard are evaluated using laser flash analysis (LFA) highlighting differences in thermal behavior under air and nitrogen aging conditions.
{"title":"Impact of Cu₂S Activity on Dielectric Properties of Oil-Paper Insulation Under Different Ambient Conditions","authors":"Leena Gautam;T. V. Shraddha;R. Sarathi;I. Fofana;T. Jayasree;U. Mohan Rao","doi":"10.1109/TDEI.2025.3563165","DOIUrl":"https://doi.org/10.1109/TDEI.2025.3563165","url":null,"abstract":"This study investigates the impact of Dibenzyl Disulfide (DBDS) on the aging and insulating properties of the pressboard used in transformer systems under varying ambient conditions. While DBDS acts as an antioxidant during the initial stages of aging, its thermal decomposition generates corrosive sulfur compounds that contribute to the chemical degradation of both the oil and pressboard insulation. These sulfur interactions in the transformer lead to the formation of copper sulfide (Cu2S), which subsequently diffuses into the pressboard, altering its thermal and electrical characteristics. Laser-induced breakdown spectroscopy (LIBS) is employed to confirm the presence of elemental copper and sulfur, indicating the Cu2S diffusion in the pressboard. The study correlates the heat trap density of the pressboard with the effects of DBDS and ambient gases on dielectric parameters. Heat trap density is identified as a critical parameter influencing the material’s electrical behavior, affecting charge storage and dissipation processes. Additionally, heat dissipation properties of the aged pressboard are evaluated using laser flash analysis (LFA) highlighting differences in thermal behavior under air and nitrogen aging conditions.","PeriodicalId":13247,"journal":{"name":"IEEE Transactions on Dielectrics and Electrical Insulation","volume":"32 4","pages":"1979-1986"},"PeriodicalIF":3.1,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144739897","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-22DOI: 10.1109/TDEI.2025.3563164
Idris Ozdemir;Halil Ibrahim Uckol;Suat Ilhan;Yazid Hadjadj;Gurkan Soykan;Abdullah Aydogan;Refat Atef Ghunem
This article investigates the erosion suppression mechanisms of zinc borate (ZB) in high-temperature vulcanized silicone rubber (SiR) using the IEC 60587 inclined plane test and simultaneous thermogravimetric (TGA)-differential thermal analysis (DTA). Alumina tri-hydrate (ATH) is employed in this study as a reference filler for comparison with ZB filler. The dehydration of ZB is reported to start around $350~^{circ }$ C, whereas ATH starts dehydration at lower temperatures around $230~^{circ }$ C. An insignificant difference is shown in the erosion resistance between the ATH and ZB-filled composites. Both fillers are shown viable in preventing the tracking and erosion failure in the IEC 60587 inclined plane test under the critical 4.5 kV ACrms voltage. ZB is found to suppress failure with the formation of residue acting as a shield against the progression of erosion. Whereas, ATH alleviates surface temperature by promoting an internal oxidation mechanism that suppresses combustion of SiR. This study’s findings highlight the potential application of ZB as a cost-effective filler in high-temperature vulcanized SiR for outdoor insulation, particularly in regions where this filler is readily available.
{"title":"Erosion Suppression of Zinc Borate Filler in HTV Silicone Rubber Under AC Dry-Band Arcing","authors":"Idris Ozdemir;Halil Ibrahim Uckol;Suat Ilhan;Yazid Hadjadj;Gurkan Soykan;Abdullah Aydogan;Refat Atef Ghunem","doi":"10.1109/TDEI.2025.3563164","DOIUrl":"https://doi.org/10.1109/TDEI.2025.3563164","url":null,"abstract":"This article investigates the erosion suppression mechanisms of zinc borate (ZB) in high-temperature vulcanized silicone rubber (SiR) using the IEC 60587 inclined plane test and simultaneous thermogravimetric (TGA)-differential thermal analysis (DTA). Alumina tri-hydrate (ATH) is employed in this study as a reference filler for comparison with ZB filler. The dehydration of ZB is reported to start around <inline-formula> <tex-math>$350~^{circ }$ </tex-math></inline-formula>C, whereas ATH starts dehydration at lower temperatures around <inline-formula> <tex-math>$230~^{circ }$ </tex-math></inline-formula>C. An insignificant difference is shown in the erosion resistance between the ATH and ZB-filled composites. Both fillers are shown viable in preventing the tracking and erosion failure in the IEC 60587 inclined plane test under the critical 4.5 kV ACrms voltage. ZB is found to suppress failure with the formation of residue acting as a shield against the progression of erosion. Whereas, ATH alleviates surface temperature by promoting an internal oxidation mechanism that suppresses combustion of SiR. This study’s findings highlight the potential application of ZB as a cost-effective filler in high-temperature vulcanized SiR for outdoor insulation, particularly in regions where this filler is readily available.","PeriodicalId":13247,"journal":{"name":"IEEE Transactions on Dielectrics and Electrical Insulation","volume":"32 4","pages":"2221-2228"},"PeriodicalIF":3.1,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144739789","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-18DOI: 10.1109/TDEI.2025.3562536
Himanshu Gupta;Mukul Srivastava;Prabhat K. Agnihotri;Sumit Basu;Nandini Gupta
Using available data from the literature and our own results, we critically examine the multifunctionality of epoxy-multiwalled carbon nanotube (MWCNT) composites. A major advantage of adding MWCNTs is that the key properties of the pristine epoxy are largely retained or even bettered. How the synthesis process affects the dispersion of the nanofillers and their properties is studied. Ideas from percolation theory are used to study and understand the nature of the variation of dc electrical conductivity with filler content and that of ac conductivity with both filler content and frequency. The electromagnetic shielding effectiveness over a broad microwave frequency range is investigated. Tensile strength, fracture properties, and thermal conductivity of the nanocomposites are also investigated. Thus, the multifunctionality of MWCNT-epoxy composites is critically assessed. Overall, we demonstrate that a deep understanding of the conduction mechanisms has been achieved. Also, the limitations of these materials have been identified and potential applications are mapped out. Their use as tough and durable electrically conductive adhesives (ECAs) is indicated. It is also shown that the major impediments to more versatile applications of these materials are their poor thermal conductivity and loss of flowability with increasing MWCNT content.
{"title":"A Critical Assessment of Electrical Conductivity and Multifunctionality of MWCNT/Epoxy Nanocomposites","authors":"Himanshu Gupta;Mukul Srivastava;Prabhat K. Agnihotri;Sumit Basu;Nandini Gupta","doi":"10.1109/TDEI.2025.3562536","DOIUrl":"https://doi.org/10.1109/TDEI.2025.3562536","url":null,"abstract":"Using available data from the literature and our own results, we critically examine the multifunctionality of epoxy-multiwalled carbon nanotube (MWCNT) composites. A major advantage of adding MWCNTs is that the key properties of the pristine epoxy are largely retained or even bettered. How the synthesis process affects the dispersion of the nanofillers and their properties is studied. Ideas from percolation theory are used to study and understand the nature of the variation of dc electrical conductivity with filler content and that of ac conductivity with both filler content and frequency. The electromagnetic shielding effectiveness over a broad microwave frequency range is investigated. Tensile strength, fracture properties, and thermal conductivity of the nanocomposites are also investigated. Thus, the multifunctionality of MWCNT-epoxy composites is critically assessed. Overall, we demonstrate that a deep understanding of the conduction mechanisms has been achieved. Also, the limitations of these materials have been identified and potential applications are mapped out. Their use as tough and durable electrically conductive adhesives (ECAs) is indicated. It is also shown that the major impediments to more versatile applications of these materials are their poor thermal conductivity and loss of flowability with increasing MWCNT content.","PeriodicalId":13247,"journal":{"name":"IEEE Transactions on Dielectrics and Electrical Insulation","volume":"32 3","pages":"1324-1332"},"PeriodicalIF":2.9,"publicationDate":"2025-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144213643","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-18DOI: 10.1109/TDEI.2025.3562533
Qian Wang;Rui Liu;Zeli Ju;Sichen Qin;Zhe Hou;Huan Lian;Rong Shi
With the continuous progress of urbanization, cross-linked polyethylene (XLPE) cable has been widely used in the construction of urban power grids. XLPE cable will deteriorate under the action of electricity, heat, and other factors for a long time, endangering the operation safety of the power grid. The trap characteristic is a significant means to reveal the mechanism of cable deterioration. To explore the relationship between cable deterioration and trap characteristics, this article uses the pulsed electroacoustic (PEA) method to analyze the trap characteristics of XLPE cables with the service life of 0, 15, and 30 years, respectively, and the sound velocity of XLPE was carried out under different temperature profiles. With the increase in operating life, the internal defects of the XLPE gradually expand, and the accumulation of charge increases significantly. The sound velocity increases gradually at the same temperature and the breakdown field strength gradually decreases. Taking 293 K as an example, compared with 0 A, the breakdown field strength of 15 and 30 A decreased by about 16.0% and 16.4%, respectively, and the corresponding medium sound velocity increased by about 5.89% and 13.71%, respectively. The results take the increase degree of sound velocity of polymer insulating medium as the characteristic parameter to characterize the deterioration level of cable, which provides a theoretical basis for evaluating the deterioration level of cable.
{"title":"The Relationship Between the Sound Velocity and Deterioration Degree of Long-Term Operation XLPE","authors":"Qian Wang;Rui Liu;Zeli Ju;Sichen Qin;Zhe Hou;Huan Lian;Rong Shi","doi":"10.1109/TDEI.2025.3562533","DOIUrl":"https://doi.org/10.1109/TDEI.2025.3562533","url":null,"abstract":"With the continuous progress of urbanization, cross-linked polyethylene (XLPE) cable has been widely used in the construction of urban power grids. XLPE cable will deteriorate under the action of electricity, heat, and other factors for a long time, endangering the operation safety of the power grid. The trap characteristic is a significant means to reveal the mechanism of cable deterioration. To explore the relationship between cable deterioration and trap characteristics, this article uses the pulsed electroacoustic (PEA) method to analyze the trap characteristics of XLPE cables with the service life of 0, 15, and 30 years, respectively, and the sound velocity of XLPE was carried out under different temperature profiles. With the increase in operating life, the internal defects of the XLPE gradually expand, and the accumulation of charge increases significantly. The sound velocity increases gradually at the same temperature and the breakdown field strength gradually decreases. Taking 293 K as an example, compared with 0 A, the breakdown field strength of 15 and 30 A decreased by about 16.0% and 16.4%, respectively, and the corresponding medium sound velocity increased by about 5.89% and 13.71%, respectively. The results take the increase degree of sound velocity of polymer insulating medium as the characteristic parameter to characterize the deterioration level of cable, which provides a theoretical basis for evaluating the deterioration level of cable.","PeriodicalId":13247,"journal":{"name":"IEEE Transactions on Dielectrics and Electrical Insulation","volume":"32 3","pages":"1263-1270"},"PeriodicalIF":2.9,"publicationDate":"2025-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144213644","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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