Pub Date : 2025-04-15DOI: 10.1109/TDEI.2025.3561093
R. Madavan;Abderrahmane Beroual;C. Thirumurugan
The insulation degradation in electrical machines is a critical concern, especially under the influence of modern power electronics-based variable frequency drives. Hence, it increases the occurrence of fast and repetitive voltage pulses on the insulation system. This review article offers a comprehensive perspective on the mechanisms and factors contributing to insulation degradation under these conditions. Review on two decades of research and development in the field, this article synthesizes findings from key studies, highlighting critical degradation processes, such as partial discharges, electrical treeing, and thermomechanical stresses are the highlights of this article. Additionally, it discusses recent advancements in mitigation strategies and design improvements aimed at enhancing insulation resilience. The insights presented herein are pivotal for improving the reliability and extending the operational lifespan of electrical machines in modern industrial applications.
{"title":"Insulation Degradation Analysis on Electrical Machines Under Fast and Repetitive Voltage Pulses: A Review","authors":"R. Madavan;Abderrahmane Beroual;C. Thirumurugan","doi":"10.1109/TDEI.2025.3561093","DOIUrl":"https://doi.org/10.1109/TDEI.2025.3561093","url":null,"abstract":"The insulation degradation in electrical machines is a critical concern, especially under the influence of modern power electronics-based variable frequency drives. Hence, it increases the occurrence of fast and repetitive voltage pulses on the insulation system. This review article offers a comprehensive perspective on the mechanisms and factors contributing to insulation degradation under these conditions. Review on two decades of research and development in the field, this article synthesizes findings from key studies, highlighting critical degradation processes, such as partial discharges, electrical treeing, and thermomechanical stresses are the highlights of this article. Additionally, it discusses recent advancements in mitigation strategies and design improvements aimed at enhancing insulation resilience. The insights presented herein are pivotal for improving the reliability and extending the operational lifespan of electrical machines in modern industrial applications.","PeriodicalId":13247,"journal":{"name":"IEEE Transactions on Dielectrics and Electrical Insulation","volume":"32 4","pages":"2485-2492"},"PeriodicalIF":3.1,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144739811","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 : 2025-04-11DOI: 10.1109/TDEI.2025.3559908
Jinru Sun;Zijia Jiao;Haoliang Liu;Zhiqiang Chen;Yupeng Chai;Xueling Yao
The peaking capacitor is a crucial component in the high-altitude electromagnetic pulse (HEMP) device. One of the significant challenges faced by the peaking capacitor is the reduction in the flashover tolerance strength of the dielectric film. This article simulates the electromagnetic environment of dielectric film and carries out flashover experiments to study the degradation characteristics of polypropylene (PP) and polyethylene terephthalate (PET) films under nanosecond pulse current injection. The effects of damage type and degree on the flashing process are analyzed by particle-in-cell Monte-Carlo-collision (PIC-MCC) method. The results show that the deformation characteristics of the film surface under nanosecond pulse current have a key influence on the flashing tolerance strength. Specifically, the raised and folded deformation of the PP film can increase the electron emission coefficient of the surface and expand the ionization range of the gas, which significantly enhances the number of electrons and reduces the flashover voltage. The microporous deformation of PET film increases the area of electron collision, but the pitted deformation restricts the diffusion of low-energy electrons. As a result, the number of electrons remains balanced, leading to a more stable flashover strength. The simulation can predict the flashover voltage of dielectric films and highly consistent with the experiments, revealing the deterioration mechanism of the film’s flashover tolerance under the action of multiple flashovers. This provides analytical methods and a theoretical basis for improving the flashover tolerance strength of dielectric films.
{"title":"Degradation Characteristics of Dielectric Film Under Nanosecond Pulse Current and the Mechanism Based on PIC-MCC Simulation","authors":"Jinru Sun;Zijia Jiao;Haoliang Liu;Zhiqiang Chen;Yupeng Chai;Xueling Yao","doi":"10.1109/TDEI.2025.3559908","DOIUrl":"https://doi.org/10.1109/TDEI.2025.3559908","url":null,"abstract":"The peaking capacitor is a crucial component in the high-altitude electromagnetic pulse (HEMP) device. One of the significant challenges faced by the peaking capacitor is the reduction in the flashover tolerance strength of the dielectric film. This article simulates the electromagnetic environment of dielectric film and carries out flashover experiments to study the degradation characteristics of polypropylene (PP) and polyethylene terephthalate (PET) films under nanosecond pulse current injection. The effects of damage type and degree on the flashing process are analyzed by particle-in-cell Monte-Carlo-collision (PIC-MCC) method. The results show that the deformation characteristics of the film surface under nanosecond pulse current have a key influence on the flashing tolerance strength. Specifically, the raised and folded deformation of the PP film can increase the electron emission coefficient of the surface and expand the ionization range of the gas, which significantly enhances the number of electrons and reduces the flashover voltage. The microporous deformation of PET film increases the area of electron collision, but the pitted deformation restricts the diffusion of low-energy electrons. As a result, the number of electrons remains balanced, leading to a more stable flashover strength. The simulation can predict the flashover voltage of dielectric films and highly consistent with the experiments, revealing the deterioration mechanism of the film’s flashover tolerance under the action of multiple flashovers. This provides analytical methods and a theoretical basis for improving the flashover tolerance strength of dielectric films.","PeriodicalId":13247,"journal":{"name":"IEEE Transactions on Dielectrics and Electrical Insulation","volume":"32 3","pages":"1297-1304"},"PeriodicalIF":2.9,"publicationDate":"2025-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144213523","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 : 2025-04-07DOI: 10.1109/TDEI.2025.3558494
Madjid Meziani;Abdelouahab Mekhaldi;Madjid Teguar
The aim of this work is to investigate the effect of frequency and the physical properties of water trees, namely, conductivity and permittivity, on the evolution of the space charge and the associated electric field distribution in the cross-linked polyethylene (XLPE) insulation under direct current (dc)and ac voltages. For this purpose, we have considered a 12-kV electric cable model with XLPE internal insulation, coated with two semiconductor layers, one inside and one outside. A pair of vented water trees, denoted as w1 and w2, is developed from these semiconductor layers. It is assumed that the permittivity and the conductivity are homogeneously distributed within the two water trees. Our study was carried out under COMSOL MULTIPHYSICS environment, using the finite element method. As main results under ac voltage, the increase of applied frequency blocks the ability of the space charge to move through the insulation, affecting both space charge density dynamic motion and electric field distribution. On the contrary, a water trees conductivity increase releases the space charge accumulated at the interfaces of the two semiconductor layers. In fact, this process amplifies the activity and dynamic behavior of such charge, facilitating its penetration into the insulation through the semiconductor layers before completely moving to two water tree tips. The same phenomenon, resulting in the complete migration of the accumulated charge from the semiconductor layers to the tips of the water trees, has also been observed in dc. The amount of this accumulated space charge leads to the electric field reinforcement especially at the XLPE insulation/water trees tips critical interfaces. This situation could generate an ac or dc electrical tree. This latter can only be initiated from the water tree tip.
{"title":"Space Charge and Associated Electric Field Distribution in Presence of Water Trees in XLPE Insulation Under DC and AC Voltages","authors":"Madjid Meziani;Abdelouahab Mekhaldi;Madjid Teguar","doi":"10.1109/TDEI.2025.3558494","DOIUrl":"https://doi.org/10.1109/TDEI.2025.3558494","url":null,"abstract":"The aim of this work is to investigate the effect of frequency and the physical properties of water trees, namely, conductivity and permittivity, on the evolution of the space charge and the associated electric field distribution in the cross-linked polyethylene (XLPE) insulation under direct current (dc)and ac voltages. For this purpose, we have considered a 12-kV electric cable model with XLPE internal insulation, coated with two semiconductor layers, one inside and one outside. A pair of vented water trees, denoted as w1 and w2, is developed from these semiconductor layers. It is assumed that the permittivity and the conductivity are homogeneously distributed within the two water trees. Our study was carried out under COMSOL MULTIPHYSICS environment, using the finite element method. As main results under ac voltage, the increase of applied frequency blocks the ability of the space charge to move through the insulation, affecting both space charge density dynamic motion and electric field distribution. On the contrary, a water trees conductivity increase releases the space charge accumulated at the interfaces of the two semiconductor layers. In fact, this process amplifies the activity and dynamic behavior of such charge, facilitating its penetration into the insulation through the semiconductor layers before completely moving to two water tree tips. The same phenomenon, resulting in the complete migration of the accumulated charge from the semiconductor layers to the tips of the water trees, has also been observed in dc. The amount of this accumulated space charge leads to the electric field reinforcement especially at the XLPE insulation/water trees tips critical interfaces. This situation could generate an ac or dc electrical tree. This latter can only be initiated from the water tree tip.","PeriodicalId":13247,"journal":{"name":"IEEE Transactions on Dielectrics and Electrical Insulation","volume":"32 3","pages":"1343-1352"},"PeriodicalIF":2.9,"publicationDate":"2025-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144213586","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}
The design of lightweight, high-power medium-voltage direct current (MVdc) cables is crucial for future all-electric aircraft (AEA) to ensure reliable performance and durability under harsh environmental conditions. These cables must effectively mitigate partial discharge (PD) and insulation degradation to support the high-power demands of next-generation aviation. In our previous work, we developed multilayer multifunctional electrical insulation (MMEI) systems to tackle these challenges. This article presents the detailed experimental studies conducted on these MMEI structures, both as flat samples and cable prototypes. Among all the designed MMEI structures, previously designed ARC-SC-T-MMEI was selected for PD study due to its multifunctionality. First, the flat sample for the selected MMEI design is fabricated, and the fabrication process is optimized by analyzing the PD characteristics observed under different fabrication conditions. Building upon these findings, a cable prototype is created using the optimized MMEI samples. Subsequently, the PD behavior of the optimized fabricated samples is investigated under varying pressure levels to replicate the actual conditions encountered in an aircraft environment. The PD behavior of this cable prototype is rigorously studied and analyzed using the Pearson correlation coefficient to assess its performance and reliability in operational conditions. Furthermore, the dielectric strength of these samples is examined under dc voltage. A two-parameter Weibull distribution is used to analyze the effect of pressure on the breakdown of the fabricated samples. This article provides detailed insights into the fabrication and performance analysis of MMEI systems under dc voltage at atmospheric and low pressures.
{"title":"Analysis of Partial Discharge Characteristics and Dielectric Strength in Multilayer Insulation Systems for MVDC Cables in Future All-Electric Wide-Body Aircraft","authors":"Anoy Saha;Saikat Chowdhury;Md Asifur Rahman;Mona Ghassemi","doi":"10.1109/TDEI.2025.3557779","DOIUrl":"https://doi.org/10.1109/TDEI.2025.3557779","url":null,"abstract":"The design of lightweight, high-power medium-voltage direct current (MVdc) cables is crucial for future all-electric aircraft (AEA) to ensure reliable performance and durability under harsh environmental conditions. These cables must effectively mitigate partial discharge (PD) and insulation degradation to support the high-power demands of next-generation aviation. In our previous work, we developed multilayer multifunctional electrical insulation (MMEI) systems to tackle these challenges. This article presents the detailed experimental studies conducted on these MMEI structures, both as flat samples and cable prototypes. Among all the designed MMEI structures, previously designed ARC-SC-T-MMEI was selected for PD study due to its multifunctionality. First, the flat sample for the selected MMEI design is fabricated, and the fabrication process is optimized by analyzing the PD characteristics observed under different fabrication conditions. Building upon these findings, a cable prototype is created using the optimized MMEI samples. Subsequently, the PD behavior of the optimized fabricated samples is investigated under varying pressure levels to replicate the actual conditions encountered in an aircraft environment. The PD behavior of this cable prototype is rigorously studied and analyzed using the Pearson correlation coefficient to assess its performance and reliability in operational conditions. Furthermore, the dielectric strength of these samples is examined under dc voltage. A two-parameter Weibull distribution is used to analyze the effect of pressure on the breakdown of the fabricated samples. This article provides detailed insights into the fabrication and performance analysis of MMEI systems under dc voltage at atmospheric and low pressures.","PeriodicalId":13247,"journal":{"name":"IEEE Transactions on Dielectrics and Electrical Insulation","volume":"32 4","pages":"2284-2293"},"PeriodicalIF":3.1,"publicationDate":"2025-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144739914","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 : 2025-04-02DOI: 10.1109/TDEI.2025.3551404
{"title":"IEEE Transactions on Dielectrics and Electrical Insulation Information for Authors","authors":"","doi":"10.1109/TDEI.2025.3551404","DOIUrl":"https://doi.org/10.1109/TDEI.2025.3551404","url":null,"abstract":"","PeriodicalId":13247,"journal":{"name":"IEEE Transactions on Dielectrics and Electrical Insulation","volume":"32 2","pages":"C4-C4"},"PeriodicalIF":2.9,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10947663","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143783202","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 : 2025-04-02DOI: 10.1109/TDEI.2025.3551410
{"title":"IEEE Transactions on Dielectrics and Electrical Insulation Publication Information","authors":"","doi":"10.1109/TDEI.2025.3551410","DOIUrl":"https://doi.org/10.1109/TDEI.2025.3551410","url":null,"abstract":"","PeriodicalId":13247,"journal":{"name":"IEEE Transactions on Dielectrics and Electrical Insulation","volume":"32 2","pages":"C2-C2"},"PeriodicalIF":2.9,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10947643","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143761565","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 : 2025-04-02DOI: 10.1109/TDEI.2025.3551408
{"title":"IEEE Dielectrics and Electrical Insulation Society Information","authors":"","doi":"10.1109/TDEI.2025.3551408","DOIUrl":"https://doi.org/10.1109/TDEI.2025.3551408","url":null,"abstract":"","PeriodicalId":13247,"journal":{"name":"IEEE Transactions on Dielectrics and Electrical Insulation","volume":"32 2","pages":"C3-C3"},"PeriodicalIF":2.9,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10947667","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143783270","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 : 2025-04-02DOI: 10.1109/TDEI.2025.3557368
Kenedy Marconi G. Santos;Marcelo B. Perotoni;Elvio P. Silva;Amélia M. Santos;Marcela S. Novo;Tagleorge M. Silveira;Polyane A. Santos;Décio R. M. Faria;Ronaldo M. Lima;Leonardo S. Caires;Marcos R. Gallego;Sérgio M. O. Tavares;Rui A. S. Moreira
Ensuring proper shielding is essential for the electromagnetic compatibility of electronic devices and systems. This article investigates the shielding effectiveness (SE) of coaxial cables and connectors using an electric field probe (EFP). This study aims to identify shielding failures early to prevent costly fixes later. A method for measuring the electric field radiated by connectors and cables in both near-field and far-field conditions is presented. Additionally, an electromagnetic virtual model of the connector and cable is developed, incorporating the dimensions and properties of the dielectric material. The simulations focus on the impact of different dielectrics on the resonant frequency of the electric field, specifically common-mode energy. The results indicate that the dielectric properties do not affect the resonant frequency in the presence of a common-mode current distribution.
{"title":"Measurement of Shielding Effectiveness in Coaxial Cables and Connectors With Various Dielectrics Using an Electric Field Probe","authors":"Kenedy Marconi G. Santos;Marcelo B. Perotoni;Elvio P. Silva;Amélia M. Santos;Marcela S. Novo;Tagleorge M. Silveira;Polyane A. Santos;Décio R. M. Faria;Ronaldo M. Lima;Leonardo S. Caires;Marcos R. Gallego;Sérgio M. O. Tavares;Rui A. S. Moreira","doi":"10.1109/TDEI.2025.3557368","DOIUrl":"https://doi.org/10.1109/TDEI.2025.3557368","url":null,"abstract":"Ensuring proper shielding is essential for the electromagnetic compatibility of electronic devices and systems. This article investigates the shielding effectiveness (SE) of coaxial cables and connectors using an electric field probe (EFP). This study aims to identify shielding failures early to prevent costly fixes later. A method for measuring the electric field radiated by connectors and cables in both near-field and far-field conditions is presented. Additionally, an electromagnetic virtual model of the connector and cable is developed, incorporating the dimensions and properties of the dielectric material. The simulations focus on the impact of different dielectrics on the resonant frequency of the electric field, specifically common-mode energy. The results indicate that the dielectric properties do not affect the resonant frequency in the presence of a common-mode current distribution.","PeriodicalId":13247,"journal":{"name":"IEEE Transactions on Dielectrics and Electrical Insulation","volume":"32 5","pages":"3097-3104"},"PeriodicalIF":3.1,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10947599","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145210026","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 : 2025-03-30DOI: 10.1109/TDEI.2025.3574950
Saeideh Alipoori;Keyvan Firuzi
Compared to conventional insulation materials, nanocomposite (NC)-based insulation systems represent novel progress in high-voltage (HV) systems, offering superior electrical, thermal, and mechanical properties. This review comprehensively analyzes the materials and fabrication methods used to develop NC insulation systems with a well-defined application, such as energy storage devices, power transmission lines, transformers, and capacitors. Nanoparticles (NPs) such as carbon nanotubes (CNTs), graphene, alumina, and boron nitride (BN) can enhance dielectric breakdown strength, mechanical robustness, and thermal conductivity. NCs offer reduced dielectric loss and adjustable permittivity, making them ideal candidates for energy storage and capacitive applications. However, some challenges remain in the large-scale fabrication of NC insulation systems. Cost considerations, controlling filler-matrix interactions, preventing NP agglomeration, achieving uniform NP dispersion within the polymer matrix, and scaling up production are key issues. Agglomeration, which leads to uneven NP distribution, negatively affects the material’s properties and performance, making it one of the major tasks to solve for improving NC systems. Developing biodegradable and recyclable NCs and exploring new nanomaterials are the future perspectives of hybrid insulation systems. This progress could result in more sustainable, multifunctional insulation materials and efficient systems for next-generation HV applications. This review outlines both the current state and prospects of NC insulation systems in power systems.
{"title":"Nanocomposite-Based Insulation Systems: A Review of Materials and Techniques for High-Voltage Applications","authors":"Saeideh Alipoori;Keyvan Firuzi","doi":"10.1109/TDEI.2025.3574950","DOIUrl":"https://doi.org/10.1109/TDEI.2025.3574950","url":null,"abstract":"Compared to conventional insulation materials, nanocomposite (NC)-based insulation systems represent novel progress in high-voltage (HV) systems, offering superior electrical, thermal, and mechanical properties. This review comprehensively analyzes the materials and fabrication methods used to develop NC insulation systems with a well-defined application, such as energy storage devices, power transmission lines, transformers, and capacitors. Nanoparticles (NPs) such as carbon nanotubes (CNTs), graphene, alumina, and boron nitride (BN) can enhance dielectric breakdown strength, mechanical robustness, and thermal conductivity. NCs offer reduced dielectric loss and adjustable permittivity, making them ideal candidates for energy storage and capacitive applications. However, some challenges remain in the large-scale fabrication of NC insulation systems. Cost considerations, controlling filler-matrix interactions, preventing NP agglomeration, achieving uniform NP dispersion within the polymer matrix, and scaling up production are key issues. Agglomeration, which leads to uneven NP distribution, negatively affects the material’s properties and performance, making it one of the major tasks to solve for improving NC systems. Developing biodegradable and recyclable NCs and exploring new nanomaterials are the future perspectives of hybrid insulation systems. This progress could result in more sustainable, multifunctional insulation materials and efficient systems for next-generation HV applications. This review outlines both the current state and prospects of NC insulation systems in power systems.","PeriodicalId":13247,"journal":{"name":"IEEE Transactions on Dielectrics and Electrical Insulation","volume":"32 4","pages":"1867-1879"},"PeriodicalIF":3.1,"publicationDate":"2025-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144739992","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}
To reduce the potential threat of water in electrical equipment, it is crucial to study the mechanisms of water accumulation in insulating oil under electrical manipulation. This study established an oil-water mixture model using molecular dynamics (MDs) simulations to quantitatively explore the dynamic evolution of water clusters under different electric fields. Key findings indicate that under a direct current (dc) electric field, polar water molecules align with the field. At dc electric field strengths (${E} _{text {DC}}$ ) below 0.50 V/nm, interactions between water molecules strengthen, leading to tighter aggregation and increased nucleation and growth rates. As ${E} _{text {DC}}$ increases, polarization intensifies, enhancing oil-water interactions, restricting water mobility, and inhibiting new nucleation. Existing droplets stretch and grow rapidly, with reduced internal density, causing structural instability. Under an alternating current (ac) electric field, water molecule orientation adjusts periodically. At electric field amplitudes $text {(}{E}_{{0}}text {)}$ below 0.50 V/nm, weak polarization and depolarization effects reduce water molecule migration. However, stronger intermolecular attraction tightens molecular aggregation, leading to increased collision frequency, which subsequently enhances nucleation and growth rates. As a result, the formed water clusters tend to hover near the center of the electric field. As ${E}_{{0}}$ exceeds 0.50 V/nm, stronger periodic polarization enhances aggregation, resulting in more vigorous motion and the formation of larger, more stable droplets. Relatively speaking, the ac field shows stronger dynamic regulation, accelerating water molecule aggregation and nucleation, particularly at ${E}_{{0}}=2.00$ V/nm. This study provides key insights into the dynamic behavior of water in electrical equipment.
{"title":"Electrically Manipulated Water Accumulation in Insulating Oil: Insights From Molecular Dynamics Simulations","authors":"Shaoqi Wang;Qiaogen Zhang;Jiahe Zhu;Tonglei Wang;Zhicheng Wu","doi":"10.1109/TDEI.2025.3571384","DOIUrl":"https://doi.org/10.1109/TDEI.2025.3571384","url":null,"abstract":"To reduce the potential threat of water in electrical equipment, it is crucial to study the mechanisms of water accumulation in insulating oil under electrical manipulation. This study established an oil-water mixture model using molecular dynamics (MDs) simulations to quantitatively explore the dynamic evolution of water clusters under different electric fields. Key findings indicate that under a direct current (dc) electric field, polar water molecules align with the field. At dc electric field strengths (<inline-formula> <tex-math>${E} _{text {DC}}$ </tex-math></inline-formula>) below 0.50 V/nm, interactions between water molecules strengthen, leading to tighter aggregation and increased nucleation and growth rates. As <inline-formula> <tex-math>${E} _{text {DC}}$ </tex-math></inline-formula> increases, polarization intensifies, enhancing oil-water interactions, restricting water mobility, and inhibiting new nucleation. Existing droplets stretch and grow rapidly, with reduced internal density, causing structural instability. Under an alternating current (ac) electric field, water molecule orientation adjusts periodically. At electric field amplitudes <inline-formula> <tex-math>$text {(}{E}_{{0}}text {)}$ </tex-math></inline-formula> below 0.50 V/nm, weak polarization and depolarization effects reduce water molecule migration. However, stronger intermolecular attraction tightens molecular aggregation, leading to increased collision frequency, which subsequently enhances nucleation and growth rates. As a result, the formed water clusters tend to hover near the center of the electric field. As <inline-formula> <tex-math>${E}_{{0}}$ </tex-math></inline-formula> exceeds 0.50 V/nm, stronger periodic polarization enhances aggregation, resulting in more vigorous motion and the formation of larger, more stable droplets. Relatively speaking, the ac field shows stronger dynamic regulation, accelerating water molecule aggregation and nucleation, particularly at <inline-formula> <tex-math>${E}_{{0}}=2.00$ </tex-math></inline-formula> V/nm. This study provides key insights into the dynamic behavior of water in electrical equipment.","PeriodicalId":13247,"journal":{"name":"IEEE Transactions on Dielectrics and Electrical Insulation","volume":"32 5","pages":"2722-2729"},"PeriodicalIF":3.1,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145189973","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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