IEEE Transactions on Dielectrics and Electrical Insulation最新文献

{"title":"Ultrathin Films of Liquid Crystal Obtained via Organic Molecular Beam Deposition Method","authors":"Anna Drzewicz;Michael Wübbenhorst","doi":"10.1109/TDEI.2025.3546175","DOIUrl":"https://doi.org/10.1109/TDEI.2025.3546175","url":null,"abstract":"The miniaturization of devices causes an increase in scientists’ interest in the possibility of creating and characterizing ultrathin layers of liquid crystals. Using organic molecular beam deposition (OMBD), organic thin layers are produced in ultrahigh vacuum by single molecule deposition on a cold substrate. In this article, we verify the possibility of creating thin films of liquid crystal below the glass transition temperature by the OMBD method. We also investigated the effect of various OMBD deposition parameters on the layer thickness and the <inline-formula> <tex-math>$alpha $ </tex-math></inline-formula>-relaxation dynamics of the compound under study. Some striking differences in relaxation dynamics related to glass-forming behavior are observed in ultrathin films compared to the bulk. We show that real time, in situ dielectric relaxation spectroscopy can be successfully applied to study the dynamic glass transition in geometric confinement, not only for simple glass-forming liquids but also for glass-forming liquid crystals using OMBD.","PeriodicalId":13247,"journal":{"name":"IEEE Transactions on Dielectrics and Electrical Insulation","volume":"32 3","pages":"1631-1638"},"PeriodicalIF":2.9,"publicationDate":"2025-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144206183","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}

{"title":"Benzydamine-Loaded Casein Nanospheres Embedded in Polyelectrolyte Multilayers","authors":"Asya Viraneva;Maria Marudova;Bissera Pilicheva;Aleksandar Grigorov;Nikolay Zahariev;Sofia Milenkova;Temenuzhka Yovcheva","doi":"10.1109/TDEI.2025.3542349","DOIUrl":"https://doi.org/10.1109/TDEI.2025.3542349","url":null,"abstract":"Polyelectrolyte multilayers (PEMs) films containing benzydamine hydrochloride (Benz)-loaded casein nanoparticles are developed aiming to increase the structure drug loading efficiency and to prolong the drug release. The multilayers are built on biodegradable polyester substrates, which are previously charged in a corona discharge. Medium viscosity sodium alginate (SA) is used as a partner in the multilayer formulation. The SA and the casein nanoparticles are deposited on the substrate using the layer-by-layer (LbL) deposition technique. The drug loading efficiency and the release kinetics in artificial saliva are determined spectrophotometrically.","PeriodicalId":13247,"journal":{"name":"IEEE Transactions on Dielectrics and Electrical Insulation","volume":"32 3","pages":"1599-1605"},"PeriodicalIF":2.9,"publicationDate":"2025-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144206129","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}

{"title":"A Methodology for Accelerated Thermal Aging of an Automotive Hairpin Stator","authors":"Juan M. Gonzalez;Leon K. Rodrigues;Filippos Beza-Florentin;Claudiu Butnaru;Mariusz Mikula;Ana Neves;João V. Sarrico","doi":"10.1109/TDEI.2025.3543806","DOIUrl":"https://doi.org/10.1109/TDEI.2025.3543806","url":null,"abstract":"This study presents a comprehensive exploration of the thermal aging of hairpin stators from a newly commissioned assembly line, tailored for automotive applications. The novelties in this article include a methodological approach that preserves material and process representativeness by testing stators directly from production. To increase sample size and stress the turn-to-turn failure mode, the star point connection is removed. Accelerated thermal aging is achieved by selecting the most aggressive set of temperatures, and expediting thermal index (TI) calculations without compromising accuracy. A detailed examination of the control parameters in the diagnostic sub-cycle is undertaken, including visual inspection, withstand voltage, capacitance, and step-by-step (SBS) impulse test with partial discharge inception voltage detection. Winding capacitance emerges as a crucial variable for tracking sample degradation, with its aging trend influenced by the measurement voltage. The introduction of the Physics of Failure (PoF) prompts an investigation into the impregnation resin as a potential factor contributing to the relatively low attained TI. The fault isolation process is generalized in a flowchart applicable to various motor types, extending its utility beyond the automotive domain.","PeriodicalId":13247,"journal":{"name":"IEEE Transactions on Dielectrics and Electrical Insulation","volume":"32 4","pages":"2195-2204"},"PeriodicalIF":3.1,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144739987","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}

{"title":"Characteristic of Surface Streamer Discharge Under the AC–DC Composite Voltage","authors":"Xiaobo Meng;Lin Lin;Hao Li;Hongwei Mei;Liming Wang","doi":"10.1109/TDEI.2025.3543792","DOIUrl":"https://doi.org/10.1109/TDEI.2025.3543792","url":null,"abstract":"The external insulation of the equipment in the valve hall of ultra high voltage (UHV) dc converter station must be able to withstand ac-dc combined voltage influences. Investigating the surface discharge characteristics of external insulation under ac-dc combined voltage is currently a significant research topic. The investigation into the surface streamer characteristics under ac-dc combined voltage is instrumental in elucidating the mechanism of surface flashover. The streamer characteristics of different phases in a single cycle under ac-dc combined voltage were determined by conducting surface streamer discharge tests. The relationship between surface streamer characteristics and different phases under ac-dc combined voltage was summarized. By comparing the test results of surface streamer discharge under dc voltage, this study analyzed the effect mechanism of ac-dc combined voltage on surface streamer characteristics. The directional motion of space charge under ac-dc combined voltage was identified as the primary determinant of surface streamer characteristics.","PeriodicalId":13247,"journal":{"name":"IEEE Transactions on Dielectrics and Electrical Insulation","volume":"32 3","pages":"1373-1379"},"PeriodicalIF":2.9,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144213641","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}

{"title":"Mechanisms for DC Breakdown Strength Degradation in Epoxy/Glass Fiber Composites Under Long-Term Aging","authors":"Ji Liu;Pengfei Wang;Chao Zhang;Zuning Huang;Longfei Zhang;Zhen Li","doi":"10.1109/TDEI.2025.3543794","DOIUrl":"https://doi.org/10.1109/TDEI.2025.3543794","url":null,"abstract":"In modern power systems, the proportion of epoxy/glass fiber (EP/GF) composites that served as the primary insulation composites in electrical equipment is steadily increasing. These devices suffer long-term electrical, thermal, and vibrational stresses during operation, leading to degradation and finally insulation failures. However, the underlying electrical-thermal–vibrational aging mechanisms of the dc breakdown performance of EP/GF composites remain unclear. In this work, combined electrical-thermal–vibrational aging experiments (1080 h) were performed on the prepared EP/GF composites. Infrared spectrum, dielectric spectrum, surface potential decay (SPD), and breakdown tests were used to characterize the functional groups, side-chain dynamics, trap levels, and dc breakdown strength of aged EP/GF composites. The research indicates that after long-term aging, the dc breakdown strength of EP/GF composites first increases by 5.8% at 72 h and then decreases by 20.6% at 1080 h. The aging of EP/GF composites is divided into recrosslinking and degradation stages. The recrosslinking stage enhances the dc breakdown strength of the EP/GF composites by reducing free volume before 72 h. While in the degradation stage, chain breaking and oxidation of epoxy chains steadily occur, introducing abundant short chains and polar groups (carbonyl and ester groups), improving free volume fraction, and accelerating chains’ dynamic. The improved free volume fraction accelerates electron avalanche in the electric field, stimulating charges to escape from traps and causing dc breakdown strength to considerably decrease during 72–1080 h.","PeriodicalId":13247,"journal":{"name":"IEEE Transactions on Dielectrics and Electrical Insulation","volume":"32 3","pages":"1498-1507"},"PeriodicalIF":2.9,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144206130","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}

{"title":"Molecular Insights Into the Effects of Thermal Oxidative Aging on the Insulation Properties of Cross-Linked Polyethylene","authors":"Wenyu Ye;Chenyu Gao;Xinhan Qiao;Haolun Che;Jianwen Zhang;Jian Hao","doi":"10.1109/TDEI.2025.3543802","DOIUrl":"https://doi.org/10.1109/TDEI.2025.3543802","url":null,"abstract":"The degradation of the insulation performance of cross-linked polyethylene (XLPE) during thermal oxidative aging is a crucial factor affecting the safe operation of cables. Investigating the influence of the structural degradation process of XLPE on its insulation properties from a molecular structure and microscopic parameter perspective can provide a better understanding of the molecular mechanisms behind insulation performance degradation during thermal oxidative aging. In this study, the reaction kinetics of XLPE were simulated using the Ab initio molecular dynamics (AIMDs), resulting in the extraction of five XLPE structures with varying degrees of aging. Density functional theory (DFT) simulations were employed to analyze the variation patterns and differences in discharge-related microscopic parameters of these five different XLPE structures under varying electric field intensities. The results show that there are significant differences in the structure and dipole moment of XLPE with different aging degrees, resulting in large changes in its microscopic parameters. In particular, the formation of carbonyl groups in XLPE has a significant impact on its structure and microscopic parameters. As the aging degree of XLPE increases, the ionization of XLPE molecules and the activity of electron affinity (EA) molecules intensify. The structural evolution of XLPE during the aging process markedly influences the excitation process and molecular orbitals of its molecules, facilitating the release of numerous photons, creating conditions for secondary electron collapse, and enhancing molecular conductivity. The simulation results of the molecular surface electrostatic potential (ESP) reveal that deeper aging of XLPE increases the likelihood of electrophilic and nucleophilic reactions, as well as electron accumulation and collision. Overall, the electric field exerts a minimal effect on the molecular structure and microscopic parameters of different XLPE molecules.","PeriodicalId":13247,"journal":{"name":"IEEE Transactions on Dielectrics and Electrical Insulation","volume":"32 4","pages":"1915-1922"},"PeriodicalIF":3.1,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144739996","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}

{"title":"Aging Failure Mechanism of Graft Modified Polypropylene Cable Insulation","authors":"Yunjian Wu;Danfeng Zhang;Yifan Guo;Fanwu Chu;Guangke Li;Xiaoxing Zhang","doi":"10.1109/TDEI.2025.3543154","DOIUrl":"https://doi.org/10.1109/TDEI.2025.3543154","url":null,"abstract":"The performance of polypropylene (PP) insulation material used in high-voltage power cables is crucial for ensuring the safe and reliable operation of the cables. To deeply understand the aging and failure mechanisms of graft-modified PP cable insulation, accelerated aging experiments were conducted on the cable insulation layer. The ac breakdown field strength and elongation at break were tested, the density functional theory calculations were performed on the graft-modified PP molecular chains, and further analyses of the physicochemical properties, such as the microstructure and molecular structure changes of the insulation material, were conducted. The results show that when the insulation material reaches the aging failure point, the breakdown performance significantly decreases, the perfection of the crystalline region structure of PP deteriorates with aging time, the content of C=O carbonyl groups significantly increases with aging time, and thermal-oxidative aging accelerates the destruction of PP spherulites. The appearance of oxidation products, structure loosening, and decreased crystallinity during the aging process are the main reasons for the reduction in mechanical performance and breakdown strength. This study provides new insights into the research on the aging mechanism, structure, and performance relationship of PP cable insulation and has important guiding significance for the design of PP insulation materials.","PeriodicalId":13247,"journal":{"name":"IEEE Transactions on Dielectrics and Electrical Insulation","volume":"32 4","pages":"2205-2212"},"PeriodicalIF":3.1,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144739899","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}

{"title":"Transformer Dissolved Gas Concentration Prediction Based on Quadratic Decomposition Reconstruction and BKA-BiLSTM","authors":"Can Ding;Donghai Yu;Xianqiao Li;Daomin Min","doi":"10.1109/TDEI.2025.3542749","DOIUrl":"https://doi.org/10.1109/TDEI.2025.3542749","url":null,"abstract":"For the prediction of each gas concentration in oil-immersed transformers, in this article, improved complete ensemble empirical mode decomposition with adaptive noise (ICEEMDAN) is first applied to the original gas data, and the sample entropy (SE) value of each subsequence is computed, the high-frequency sequences with the highest SE are subjected to quadratic variational mode decomposition (VMD) to further reduce the degree of its instability, that is, the ICEEMDAN-SE-VMD decomposition model is formed. Second, reconstruction operations are performed on the subsequences with close SE values after ICEEMDAN decomposition to reduce the prediction time while ensuring the accuracy. Finally, a bidirectional long short-term memory with attention mechanism (Bi-LSTM-AT) is used to predict each subsequence separately; for the optimization of the parameters in prediction algorithms, the latest black-winged kite algorithm (BKA) is used in this article for optimization of the parameters, and the prediction results of the subsequence are superimposed to be the final prediction value for the gas concentration. The prediction results of the six gases produced by the transformer show that compared with other methods, the prediction method used in this article reduces the prediction time, while the prediction accuracy is also guaranteed.","PeriodicalId":13247,"journal":{"name":"IEEE Transactions on Dielectrics and Electrical Insulation","volume":"32 4","pages":"2433-2442"},"PeriodicalIF":3.1,"publicationDate":"2025-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144739863","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}

{"title":"Analytical Model for Transient Space Charge in Low-Density Polyethylene","authors":"Purnabhishek Muppala;C. C. Reddy","doi":"10.1109/TDEI.2025.3541613","DOIUrl":"https://doi.org/10.1109/TDEI.2025.3541613","url":null,"abstract":"Despite being an experimentally well-studied phenomena, a consistent lacuna has always persisted in the theoretical and mathematical understanding of space charge dynamics in low-density polyethylene (LDPE). The macroscopic models reported so far in the literature seem to be insufficient and fail to predict the formation of homo- and hetero-charges near the electrodes and transport of charge packets. On the other hand, while microscopic models such as bipolar charge transport (BCT) model were able to explain homo-charge accumulation and movement of charge packets to a limited success, they are often fraught with assumptions such as neglection of diffusion phenomena and are structurally complicated when compared to macroscopic models. In this work, the authors have derived analytical solutions for space charge dynamics based on Maxwell’s equations and transient space charge limited current (TSLC)-based volumetric current models, which take into consideration the measured absorption (slow polarization) and steady-state volumetric currents. The proposed analytical (macroscopic) model can thus predict the homo- and hetero-charge accumulation in LDPE, which is validated through comparisons with the experimentally measured space charge, wherein a remarkable agreement was observed. Furthermore, the relation between the transient volumetric current and space charge dynamics is reaffirmed.","PeriodicalId":13247,"journal":{"name":"IEEE Transactions on Dielectrics and Electrical Insulation","volume":"32 3","pages":"1567-1574"},"PeriodicalIF":2.9,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144205931","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}

{"title":"Enhancing Insulator String Performance: Pollution and Icing Flashover Analysis Through Artificial Neural Network-Based Layout Optimization for Inverted T-Type String","authors":"Mahmoud A. Ali;Xingliang Jiang;Salah Kamel;Asad Awan","doi":"10.1109/TDEI.2025.3542009","DOIUrl":"https://doi.org/10.1109/TDEI.2025.3542009","url":null,"abstract":"This study explores the impact of various high-voltage insulator string configurations on pollution and icing flashover characteristics under different environmental conditions. The inverted T-string design is suggested, offering improvements over the traditional I-string configuration. An experimental investigation is conducted using high-voltage glass-type disks (LD-160), along with the development of two artificial neural network (ANN) models to simulate and predict flashover voltages. The results demonstrate that the inverted T-string arrangement enhances the flashover voltage for polluted insulator strings by approximately 7% and increases the icing flashover voltage by 3.43%–5.01% compared to standard I-strings. The ANN models successfully determine optimal insulator configurations, demonstrating their potential to enhance high-voltage insulation performance with minimal experimentation. This study emphasizes the innovative use of ANN in optimizing insulator string arrangements, providing a practical solution for tackling pollution and icing issues in power systems.","PeriodicalId":13247,"journal":{"name":"IEEE Transactions on Dielectrics and Electrical Insulation","volume":"32 3","pages":"1653-1659"},"PeriodicalIF":2.9,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144205972","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}