IEEE Transactions on Dielectrics and Electrical Insulation最新文献

{"title":"Discharge Monitoring and Aging Assessment Method for Metallized Film Capacitor Based on Acoustic Signal","authors":"Linzi Zheng;Shengchang Ji;Xinyi Yan;Zhili Li;Qiming Sun;Lingyu Zhu","doi":"10.1109/TDEI.2024.3460733","DOIUrl":"10.1109/TDEI.2024.3460733","url":null,"abstract":"In modular multilevel converters (MMCs) of HVDC systems, metallized film capacitors (MFCs) are commonly used as dc-link capacitors. Based on the unique feature of the self-healing discharge, MFCs can clear internal defects and maintain operation stability. However, self-healing discharge can cause continuous aging of MFCs due to the accumulation of electrode area loss. Although electrical parameters are sufficiently investigated to monitor the operating states of MFCs, the correlation between discharge characteristics and aging states remains unclear based on these parameters. To address this issue, this article provides a novel perspective by proposing a discharge monitoring and aging assessment method based on the acoustic signal. First, an accelerated aging platform is established to obtain MFC samples in different aging degrees. Then, the acoustic signal and the pulse current signal of MFC samples are detected to demonstrate the feasibility of using acoustic signals as characteristic parameters. Furthermore, the processed discharge data are subject to cluster analysis to investigate the relationship between discharge statistic characteristics and the aging states of MFCs. The results indicate that the aging states of MFCs can be assessed using the frequency spectrum characteristics and the cluster ratio of acoustic signals, guiding future research on the monitoring methods of MFCs using nonelectrical parameters.","PeriodicalId":13247,"journal":{"name":"IEEE Transactions on Dielectrics and Electrical Insulation","volume":"32 1","pages":"11-19"},"PeriodicalIF":2.9,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142261352","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":"Surface Partial Discharge Characteristics Under Repeated Positive Triangular High Voltages (1 kV/s)","authors":"Pantelis N. Mikropoulos;Pavlos K. Samaras","doi":"10.1109/TDEI.2024.3460735","DOIUrl":"10.1109/TDEI.2024.3460735","url":null,"abstract":"In DC insulation systems, surface partial discharge activity is of major concern, in addition to the normal operating conditions, under transient stress conditions relating to energization and de-energization, voltage polarity reversal, and overvoltage surges. In this study, surface partial discharges in a short sphere-plane gap bridged by polymeric insulating surfaces are investigated under positive triangular high voltages. Discharge modes and their salient characteristics as affected by the applied electric field and insulating material are evaluated and discussed based on current measurements. Emphasis is further given to assess the dependence of surface partial discharge activity on the rise and fall of the applied voltage, repeated testing as well as upon surface charging. Surface discharges are initiated in pulse mode at significantly lower voltages than that observed in air alone; however, the stable glow discharge is established and maintained at markedly higher voltages although related to lower continuous current with greater fluctuation, especially for insulating materials with lower relative permittivity. These are attributed to space and surface charges associated with preceding discharges.","PeriodicalId":13247,"journal":{"name":"IEEE Transactions on Dielectrics and Electrical Insulation","volume":"32 2","pages":"958-966"},"PeriodicalIF":2.9,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142261355","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":"Catalytic Effects of Iron and Copper on Degradation of Natural Esters at Different Temperatures","authors":"Xuefeng Hu;Haoxi Cong;Xuan Zhang;Yuxuan Wang;Yulin Du;Qingmin Li","doi":"10.1109/TDEI.2024.3460732","DOIUrl":"10.1109/TDEI.2024.3460732","url":null,"abstract":"Natural esters are renewable, highly available, and have a high ignition point. It is considered a suitable alternative to mineral oil in the future development of low-carbon networks and smart grids. The bare silicon steel and copper used in transformers can promote aging of natural esters and shorten their service life. In this article, natural esters containing copper and iron are used for accelerated thermal aging at 100 °C, 120 °C, and 140 °C, and the physicochemical and electrical properties of the natural esters are tested. It is shown that the physicochemical and electrical properties of natural esters are substantially destroyed with increasing temperature. Copper is more catalytic and conductive, resulting in natural esters containing copper having inferior physicochemical and electrical property indices than those containing iron. However, the measured content of iron ions in the oil is much higher than that of copper ions in the oil. It can be seen that the catalytic ability of metals mainly depends on the elemental species rather than the elemental content. The above studies can provide theoretical guidance to reveal the mechanism of deterioration of natural esters by temperature and transition metals in transformers with bare copper and steel.","PeriodicalId":13247,"journal":{"name":"IEEE Transactions on Dielectrics and Electrical Insulation","volume":"32 1","pages":"342-348"},"PeriodicalIF":2.9,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142261353","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":"Nanodielectric Fluids for Power Transformer Insulation and Cooling: A Review Identifying Challenges and Future Research Needs","authors":"Sai Pavan Kalakonda;Mona Ghassemi","doi":"10.1109/TDEI.2024.3459861","DOIUrl":"10.1109/TDEI.2024.3459861","url":null,"abstract":"It is becoming increasingly common for many oil-immersed power transformers (PTs) in many countries, including USA, to reach the end of their designed service life. Insulation issues fundamentally cause transformer failure. Due to the significant capital cost, customized design, and long lead time for delivery, it is less desirable to replace these essential element assets, especially for large ones. Instead, exploring novel insulation systems that may be used to upgrade existing oil-immersed transformers is considered. On the other hand, novel insulation systems that improve electrical insulation and thermal management are also attractive for new PTs, which lead to higher density designs. This review investigates nanodielectric fluids (NDFs) as alternatives to transformer oils. NDFs are nanofluids (NFs) wherein the base fluid is dielectric. Adding different nanoparticles (NPs) to the dielectric liquids will result in nanodielectric liquids. Choi and Eastman in 1995 revolutionized the area of PT oil research by inventing NFs that are said to have enhanced thermal transport properties. Similar investigations on PT oils led to the discovery that NPs are capable of enhancing the dielectric properties as well. This revolutionary research field has piqued the interest of many researchers, scientists, and industrialists all over the world. However, it is not easy to synthesize an NDF just by mixing any NP with PT oils. Several factors, such as NDF stability, NP concentration, size, shape, NDF viscosity, choice of surfactant, concentration of surfactant, time of ultrasonication, and cost, should be considered while synthesizing an NDF. Although many studies have been conducted using various base fluids and NPs, commercial NDFs for PTs have yet to be realized. This article critically reviews investigations done on NDFs for PTs, identifies technical gaps, and highlights future research needs. As a result, it can be a valuable source for further research.","PeriodicalId":13247,"journal":{"name":"IEEE Transactions on Dielectrics and Electrical Insulation","volume":"32 1","pages":"349-366"},"PeriodicalIF":2.9,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10679660","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142212987","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}

{"title":"Simulation Study of the Measurement Characteristics of Equipotential Shielding Capacitor Voltage Divider","authors":"Fanghui Yin;Shilin Shi;Jianchao Li;Bo Li;Liming Wang;Jianchao Zheng;Masoud Farzaneh","doi":"10.1109/TDEI.2024.3457511","DOIUrl":"10.1109/TDEI.2024.3457511","url":null,"abstract":"The online measurement of transient voltages is crucial for maintaining the reliability and safety of ac power systems. With the construction of UHV/EHV ac power systems, the voltage levels of ac equipment continue to increase, and traditional capacitor voltage dividers (CVDs) become unreliable due to the instability of their ground capacitance. This article proposes an equipotential shielding CVD (ES-CVD) and conducts simulation research on its measurement characteristics. The results show that a stable measurement can be guaranteed when the distance to the ground is greater than ten times the diameter of the measuring spherical conductor. The ES-CVD can effectively prevent the electric field strength on the surface of the measuring spherical conductor from exceeding the critical discharge field strength. The high-voltage wire to be measured and adjacent high-voltage wires have a significant impact on the ground capacitance of the measuring spherical conductor. However, the shielding electrode can significantly reduce their impact. Compared to a CVD without a shielding electrode, a divider with a shielding electrode can reduce the measurement error by one order of magnitude, which meets the measurement requirements of transient voltage. The research results in this article can provide a reference for measuring high-voltage ac transient voltage.","PeriodicalId":13247,"journal":{"name":"IEEE Transactions on Dielectrics and Electrical Insulation","volume":"32 2","pages":"849-858"},"PeriodicalIF":2.9,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142212881","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":"Improved Dielectric Properties of Polypropylene Films by Electron-Beam Irradiation Modification for Power Capacitor","authors":"Meng Xiao;Yuyan Chen;Haoliang Liu;Boxue Du","doi":"10.1109/TDEI.2024.3457534","DOIUrl":"10.1109/TDEI.2024.3457534","url":null,"abstract":"The dielectric properties of polypropylene (PP) for metalized film capacitors (MFCs) decrease significantly at high temperatures, affecting the reliable operation of capacitors. In this article, a method of improving the high-temperature dielectric properties of PP films based on electron-beam (EB) irradiation modification is proposed. PP films doped with pentaerythritol triacrylate (PETA) are prepared and irradiated with doses of 0–20 kGy under EB rays. The intrinsic correlation among the irradiation dose, crosslinking structure, and the dielectric properties of PP films is investigated. The improvement in dielectric strength is most significant for the PP film samples with a crosslinking degree of up to 17.4%. The dc breakdown strength and conductivity of PP15 are 561 kV/mm and <inline-formula> <tex-math>$1.12times 10^{-{13}}$ </tex-math></inline-formula> at 125° C, respectively. The discharged energy density is 2.96 J/cm3 with the charge-discharge efficiency of 75.0%. The results show that the rigid structure impedes the bending and slipping of molecular chains at high temperatures, improving the heat resistance of PP. This study illustrates that the application of irradiation crosslinking modification improves the dielectric properties of PP films.","PeriodicalId":13247,"journal":{"name":"IEEE Transactions on Dielectrics and Electrical Insulation","volume":"32 2","pages":"699-706"},"PeriodicalIF":2.9,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142212991","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":"Microscopic Mechanism Effect of Oxygen and Moisture on Pyrolysis of Transformer Insulating Paper","authors":"Haoxi Cong;Shaomin Quan;Xuefeng Hu;Xuan Zhang;Qingmin Li;Mingrong Xu","doi":"10.1109/TDEI.2024.3456771","DOIUrl":"10.1109/TDEI.2024.3456771","url":null,"abstract":"Cellulose paper constitutes a crucial element of oil-paper insulation, crucially influencing the lifespan of transformers. Throughout its aging process, the cellulose paper generates moisture, while the insulating oil contains varying levels of oxygen. Understanding the aging mechanism of cellulose paper necessitates an exploration of the synergistic interplay between moisture and oxygen. This article establishes models incorporating varying moisture, oxygen, and cellobiose concentrations. Molecular dynamics simulations employing the reactive force field (ReaxFF) are employed to investigate the effects of moisture and oxygen addition on the decomposition of cellobiose. The mechanisms underlying the effects of moisture and oxygen on cellobiose decomposition are examined. The changes in the content of the major end products, including H2O, CO2, CO, HCHO, and HCOOH, are also analyzed. It is found that oxygen promotes the formation of C = O bonds and the production of free H from cellobiose. Moisture provides free H and promotes further reactions. The synergistic effect of moisture and oxygen accelerates the aging process of cellulose paper. This investigation provides theoretical support for further research into the aging mechanism of cellulose paper.","PeriodicalId":13247,"journal":{"name":"IEEE Transactions on Dielectrics and Electrical Insulation","volume":"32 2","pages":"1008-1016"},"PeriodicalIF":2.9,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142226980","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":"Voltage Endurance Characteristics of Cross-Linked Polyethylene–Silicone Rubber Interface Subjected to DC and AC Voltages","authors":"Xiaodong Li;Hao Hu;Kairun Song;Zhengxue Wang;Zhidong Jia","doi":"10.1109/TDEI.2024.3456773","DOIUrl":"10.1109/TDEI.2024.3456773","url":null,"abstract":"When designing and inspecting power equipment, it is crucial to consider not only the distinctions between ac, dc, and ac–dc hybrid systems but also the voltage endurance characteristics. However, scientific design and research on the mechanism responsible for the breakdown of solid-solid interfaces (e.g., cable joints), which are weak points in electrical insulation, is lacking. Therefore, in this study, the insulating strength of the interface in relation to the electric field form and voltage endurance time is examined. Specifically, the increase in the insulation strength and the ablation of cross-linked polyethylene–silicone rubber (XLPE–SiR) interfaces are investigated based on the ramped breakdown and step-stress methods. The results illustrate that the dc breakdown strength surpasses the ac breakdown strength, while the ac field fails to reach the composite (ac–dc) electric field breakdown strength. Furthermore, the interfacial breakdown strength is influenced by both long-term and transient stresses. The interfacial breakdown process can be divided into three stages. The breakdown voltage increases in the short term with decreasing step-up rate. Step-stress tolerance experiments and simulations indicate that the highly distorted electric field at asperity contacts leads to cavity discharges and electrothermal losses, resulting in the ablation of the asperities on the rough surface. The electric field distortion decreases with decreasing interface roughness, leading to an increase in breakdown strength. Moreover, as the endurance time increases, the improvement of the ac breakdown strength is more significant than that of the composite electric field, while the dc breakdown strength shows the least improvement.","PeriodicalId":13247,"journal":{"name":"IEEE Transactions on Dielectrics and Electrical Insulation","volume":"32 2","pages":"690-698"},"PeriodicalIF":2.9,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142212989","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":"Effect of Isotacticity on Thermal Oxidative Aging Performance of Polypropylene Films for HVDC Capacitors","authors":"Meng Xiao, X. D. Du, B. X. Du","doi":"10.1109/tdei.2024.3456786","DOIUrl":"https://doi.org/10.1109/tdei.2024.3456786","url":null,"abstract":"","PeriodicalId":13247,"journal":{"name":"IEEE Transactions on Dielectrics and Electrical Insulation","volume":"8 1","pages":""},"PeriodicalIF":3.1,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142212990","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 Novel Dual-Stage Semi-Supervised Learning Model for Fault Diagnosis in Transformers with Limited Imbalanced Labeled Data","authors":"Yanfei Sun, Tao Zhao, Shuguo Gao","doi":"10.1109/tdei.2024.3456777","DOIUrl":"https://doi.org/10.1109/tdei.2024.3456777","url":null,"abstract":"","PeriodicalId":13247,"journal":{"name":"IEEE Transactions on Dielectrics and Electrical Insulation","volume":"107 1","pages":""},"PeriodicalIF":3.1,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142212988","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}