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":"Locating Water-Tree Degraded Cable Section by Measuring Residual Charges Induced by Voltage Pulse Wave","authors":"May Thin Khaing;Koki Watanabe;Tatsuya Sakoda;Toru Takayama;Kazunori Miyazaki","doi":"10.1109/TDEI.2025.3545010","DOIUrl":"https://doi.org/10.1109/TDEI.2025.3545010","url":null,"abstract":"A residual charge method is useful for measuring water tree in 22-kV crosslinked polyethylene (XLPE) cable systems. However, the conventional residual charge method cannot locate a water-tree degraded cable section because the time-resolved signal response from a water-tree degradation section cannot be obtained. In this study, we inject a sine wave pulse with a frequency of 1 MHz into measuring object cables when ac voltage is applied to the cables to release trapped charges due to the water-tree. We examine to locate a water-tree degraded cable section in 22-kV XLPE cable systems, including water-tree degraded cables and a Y-branch cable joint. The time-resolved residual charges induced by the voltage pulse induced by an injection coil (IJ coil) can locate a water-tree degraded cable section.","PeriodicalId":13247,"journal":{"name":"IEEE Transactions on Dielectrics and Electrical Insulation","volume":"32 5","pages":"2915-2921"},"PeriodicalIF":3.1,"publicationDate":"2025-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145189982","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":"Two-Dimensional Charge Characteristics in HVDC GIL Insulators: A Simulation Study","authors":"Xi Pang;Peng Liu;Pengfei Zhang;Zongliang Xie;Tianlei Xu;Dingxin Wei;Zongren Peng","doi":"10.1109/TDEI.2025.3544165","DOIUrl":"https://doi.org/10.1109/TDEI.2025.3544165","url":null,"abstract":"The long-term synergistic effects of high-voltage direct current (HVDC) and temperature gradients inevitably stimulate charge accumulation in gas-insulated transmission line (GIL) insulators, which significantly increases the risk of insulation failure. Due to the limitations in charge measurement techniques, it is crucial to develop effective methods for accurately simulating and evaluating the dynamic charge behaviors of GIL insulators under complex operating conditions. In this study, we present a 2-D bipolar charge transport and interaction (2-D BCTI) model that accounts for both space charge and surface charge dynamics. Such a model is employed to investigate the charge behaviors of HVDC GIL insulators under varying electric fields, polarization time, and voltage polarities. Our findings indicate that higher voltages and extended polarization time lead to increased charge migration and localized accumulation within the insulator. Further analysis reveals that the surface potential at the high-voltage terminal interface is predominantly influenced by the tangential current (<inline-formula> <tex-math>${J}_{text {s}}$ </tex-math></inline-formula>) along the insulator’s surface and bulky current (<inline-formula> <tex-math>${J}_{text {v}}$ </tex-math></inline-formula>) passing through the insulator. In other regions of the basin insulator, such as the shielding ring and grounding terminal, <inline-formula> <tex-math>${J}_{text {s}}$ </tex-math></inline-formula> is the dominant factor. This study provides valuable theoretical insights into the interaction between surface and space charge, offering a foundation for optimizing the insulation design of HVDC GIL systems.","PeriodicalId":13247,"journal":{"name":"IEEE Transactions on Dielectrics and Electrical Insulation","volume":"32 5","pages":"3039-3048"},"PeriodicalIF":3.1,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145189969","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 Method of Kernel Principal Component Analysis and Machine Learning Algorithms for Fault Diagnosis of Power Transformers","authors":"Zhou Li;Fanrong Wang","doi":"10.1109/TDEI.2025.3543337","DOIUrl":"https://doi.org/10.1109/TDEI.2025.3543337","url":null,"abstract":"As one of the most important equipment in the power system, it is of great significance to conduct fault diagnosis research on transformers. Aiming at the problem of difficult selection of parameters for support vector machine (SVM) in transformer fault diagnosis, a fault diagnosis model based on the improved pelican optimization algorithm (IPOA) optimized SVM is proposed. First, the standard pelican optimization algorithm (POA) is enhanced by introducing the Tent chaotic mapping, Levy flight strategy, and adaptive weighting strategy, and the superiority of the IPOA algorithm is verified by comparing its performance with other intelligent algorithms across four test functions. Second, feature dimensionality reduction of the data samples is performed using kernel principal component analysis (KPCA), and the IPOA algorithm is used to optimize the SVM parameters and then establish the transformer fault diagnosis model based on IPOA-SVM. Finally, the POA-SVM, northern goshawk optimization (NGO)-SVM, GWO-SVM, whale optimization algorithm (WOA)-SVM, and particle swarm optimization (PSO)-SVM models are used to conduct comparative experiments with the proposed method. The results show that the diagnostic accuracy of the IPOA-SVM model reaches 95%, which is 3.75%, 5.0%, 6.25%, 7.5%, and 8.75% higher than that of the POA-SVM, NGO-SVM, GWO-SVM, WOA-SVM, and PSO-SVM diagnostic models, respectively; and the proposed model exhibits better stability and greater adaptability.","PeriodicalId":13247,"journal":{"name":"IEEE Transactions on Dielectrics and Electrical Insulation","volume":"32 5","pages":"3068-3077"},"PeriodicalIF":3.1,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145210034","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":"Analysis and Diagnosis of Optical and UHF Partial Discharges in GIS Based on Guided Filtering Fusion","authors":"Ze Li;Yiming Zang;Chenglin Wang;Yanshu Tang;Tongyang Ren;Xiuchen Jiang","doi":"10.1109/TDEI.2025.3543147","DOIUrl":"https://doi.org/10.1109/TDEI.2025.3543147","url":null,"abstract":"The optical method and ultrahigh frequency (UHF) method are important techniques for detecting partial discharge (PD) in gas-insulated switchgear (GIS). However, optical signals and UHF signals may suffer from different degrees of signal loss or interference for different PD types, which leads to incomplete feature information in the optical or UHF patterns and reduces the accuracy of pattern recognition. In this article, a PD detection device in GIS based on the UHF and light guide rod (LGR) technologies is designed. An experimental platform for electrical and optical PD detection in GIS is set up, and measurements of typical PD are carried out. Optical and UHF time-domain signals of corona discharge, floating discharge, and particle discharge are obtained. Then, an image fusion algorithm based on guided filtering fusion (GFF) is proposed to fuse the optical and UHF phase-resolved pulse sequence (PRPS) patterns. Subsequently, a feature extraction method based on speeded-up robust features (SURFs) for PD images is proposed. Finally, the recognition effects of multiple classifiers are compared. The results show that the image fusion and feature extraction method for UHF and optical PD proposed in this article can improve the accuracy of fault diagnosis up to 97.1%.","PeriodicalId":13247,"journal":{"name":"IEEE Transactions on Dielectrics and Electrical Insulation","volume":"32 5","pages":"2978-2985"},"PeriodicalIF":3.1,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145189970","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}