IEEE Transactions on Dielectrics and Electrical Insulation最新文献

{"title":"Rubber Particles Motion in Mineral Oil Under AC Voltage by Schlieren Imaging and Numerical Simulation","authors":"Yun Liao;Wenfu Wei;Zefeng Yang;Wenlong Liao;Jiazhao Lian;Kaifang Jiang;Jie Yong;Guangning Wu","doi":"10.1109/TDEI.2024.3503542","DOIUrl":"https://doi.org/10.1109/TDEI.2024.3503542","url":null,"abstract":"Transformer oil is inevitably contaminated with impurity particles during actual transformer operations. The motion of these impurity particles in transformer oil poses a potential threat to the insulation performance. While many studies have researched the motion of fibers, metals, and carbon particles causing breakdown in transformer oil, research on rubber particles remains unexplored. Due to aging, rubber components in transformers partially detach and suspend in the transformer oil in the form of particles. This study establishes the breakdown test platform for the mineral oil under ac voltage. Using the high-speed camera and Schlieren imaging method, the motion characteristics of rubber particles in the mineral oil and their impact on mineral oil breakdown are investigated. Meanwhile, through fluid-electric field coupling simulation, the motion characteristics of rubber particles from individual motion to collective behavior are analyzed. The results indicate that the particles outside the electrode gap presented different movement trends, determined by their initial spatial location and size, whereas rubber particles inside the electrode gap begin to reciprocate and aggregate into walls, raising the breakdown probability. This study is helpful for a better understanding of the impact of impurity particles on the insulation performance of transformers.","PeriodicalId":13247,"journal":{"name":"IEEE Transactions on Dielectrics and Electrical Insulation","volume":"32 3","pages":"1508-1517"},"PeriodicalIF":2.9,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144205930","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":"Partial Discharge Aging of Epoxy Insulation at Different High-Frequency Pulse Parameters and Environmental Stresses","authors":"Xingyu Shang;Lei Pang;Qinhao Bu;Qiaogen Zhang","doi":"10.1109/TDEI.2024.3502581","DOIUrl":"https://doi.org/10.1109/TDEI.2024.3502581","url":null,"abstract":"The voltage stress on high-frequency transformers (HFTs) features higher levels of repetition frequency, operating voltage, voltage dV/dt, and grid voltage superposition, which challenges the epoxy insulation of HFTs exposed to partial discharges (PDs). Wide ranges of voltage parameters (frequency, voltage, rising edge, and dc bias) and environmental stresses (temperature, humidity, gas, and pressure) are applied to the sphere-gap-insulation-plate structure for PD aging analysis. New patterns are found in this study. For example, the shape of the rising edge affects the lifetime, and the influences of humidity and dc bias are nonmonotonic. Surface charge decay and voltage dV/dt have key effects on the discharge pattern. Early failures with pulse frequencies of 50 and 100 kHz are attributed to the interaction of humidity and electric field. The erosion rate is lower at oxygen-free ambient, while higher with CO2 gas. PD parameters (PD number, PD amplitude, PD delay, PD ignition voltage, and PD frequency) and phase-resolved PD (PRPD) patterns are measured with the ultrahigh-frequency (UHF) method and discussed for all aging conditions. Cumulative PD amplitude and cumulative PD energy have a good correlation to experimental lifetime values. However, due to the transition of the PD regime, the fit model has less explainability on the influence of voltage, humidity, gas, and pressure on the lifetime, which is rarely revealed before.","PeriodicalId":13247,"journal":{"name":"IEEE Transactions on Dielectrics and Electrical Insulation","volume":"32 1","pages":"45-54"},"PeriodicalIF":2.9,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143106314","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 Crosslinking Agent Content on Dielectric Properties of PP Films Modified by EB Irradiation for HVDC Capacitor","authors":"Meng Xiao;Yuyan Chen;Haoliang Liu;Boxue Du","doi":"10.1109/TDEI.2024.3502000","DOIUrl":"https://doi.org/10.1109/TDEI.2024.3502000","url":null,"abstract":"The decline in breakdown strength and the rise in dielectric loss of polypropylene (PP) film at high temperatures are the key factors restricting the application of metalized film capacitors (MFCs). This article proposed a modification method using electron-beam (EB) irradiation to improve the high-temperature insulation performance of PP film for capacitors. The influence of crosslinking agent contents on the dielectric properties of irradiated crosslinked PP is investigated. The results show that the conductivity of EB-irradiated films doped with 0–2 wt% pentaerythritol triacrylate (PETA) is reduced by 26.9%–60.8% and the breakdown strength is enhanced by 2.8%–21.2% at <inline-formula> <tex-math>$125~^{circ }$ </tex-math></inline-formula>C, resulting in better dielectric properties compared to pure PP films. The formation of a 3-D network structure by crosslinking can inhibit the thermal motion of molecular chains and improve their thermal stability, consequently limiting the transport behavior of carriers. Irradiation crosslinking modification can improve the high-temperature dielectric properties of PP films. This research provides a valuable reference for the crosslinking modification of PP films serving in MFCs.","PeriodicalId":13247,"journal":{"name":"IEEE Transactions on Dielectrics and Electrical Insulation","volume":"32 2","pages":"734-741"},"PeriodicalIF":2.9,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143761393","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":"Accelerated Laboratory Aging of Synthetic Ester Dielectric Liquid","authors":"Veronika Haramija;Dijana Vrsaljko;Vedran Ðurina;Domagoj Vrsaljko","doi":"10.1109/TDEI.2024.3501995","DOIUrl":"https://doi.org/10.1109/TDEI.2024.3501995","url":null,"abstract":"Synthetic esters are liquids used in the lubricant industry, but also in the electrical industry for insulation and heat transfer. In this work, the synthetic ester is exposed to high temperatures to initiate and propagate the degradation reactions, study the degradation process, and investigate the effect of paper and water on thermal degradation. After 672 h of thermal exposure, there is no sludge, but the color of the samples is significantly changed. Fourier transform infrared spectroscopy (FTIR) is used to assess the occurrence of degradation products, the neutralization value is used to determine the total acidity, and the relative permittivity is used to correlate the influence of degradation products on the dielectric properties of the synthetic ester. Nuclear magnetic resonance (NMR) and color analysis are used to investigate the appearance and composition of the degradation products of seven selected samples. The NMR study shows that the change observed in the FTIR spectra, the neutralization value, and the relative permittivity as a function of aging conditions correspond very well with the size and shape of the 1 H NMR peak of 3.51 ppm, confirming that the formation of alcohols, ethers, and cross-links is responsible for the aging of the ester. It is found that the color change is misleading when it comes to the degradation of the synthetic ester dielectric liquid.","PeriodicalId":13247,"journal":{"name":"IEEE Transactions on Dielectrics and Electrical Insulation","volume":"32 1","pages":"367-374"},"PeriodicalIF":2.9,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143106308","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":"Space Charge Simulation Model for Bilayer Oil-Impregnated Paper Insulation Based on Multiple Discrete Trap Energy Levels","authors":"Meng Huang;Lu Wang;Zilu Wang;Shilonng Niu;Weiguang You;Bo Qi","doi":"10.1109/TDEI.2024.3501999","DOIUrl":"https://doi.org/10.1109/TDEI.2024.3501999","url":null,"abstract":"Space charge-induced electric field distortion seriously threatens dielectric insulation properties. However, there are fewer simulation studies on the interfacial charge of the same dielectric structure, such as bilayer oil-impregnated paper. In this article, based on the bipolar carrier transport model, a multiple discrete trap energy levels carrier transport model is proposed to simulate the space charge distribution of the bilayer oil-impregnated paper structure, taking the fast charge migration process into account. The results show that the maximum error of charge distribution under positive and negative polarity applied voltage is about 7.42% and 3.93%, respectively, and the simulation results are in good agreement with the experimental results. The effect of relaxation polarization on the polarization current is analyzed, and the polarization current simulation values considering relaxation polarization agree well with the experimental values, with a maximum error of about 7.3%. We find that the fast charge migration process is the root cause and the main source of the interfacial charge accumulation of the same medium. The introduction of the fast migration process ensures that the polarity of the interfacial charge accumulation is the same as that of the semi-conducting electrode, and the interfacial charge peaks all have a tendency to shift from the semi-conducting electrode side to the metal electrode side. The study in this article can provide a mechanism explanation for characterizing the migration mechanism of bilayer oil-impregnated paper structure and the origin of interfacial charge accumulation.","PeriodicalId":13247,"journal":{"name":"IEEE Transactions on Dielectrics and Electrical Insulation","volume":"32 3","pages":"1442-1450"},"PeriodicalIF":2.9,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144213521","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":"Effects of Thermo-Oxidative Aging on the Dielectric Property and Electrical Breakdown of Epoxy Resin Using in High-Voltage Equipment","authors":"Xiaoxiao Kong;Chong Zhang;H. S. Du;H. Miyake;Y. Tanaka;Boxue Du","doi":"10.1109/TDEI.2024.3501997","DOIUrl":"https://doi.org/10.1109/TDEI.2024.3501997","url":null,"abstract":"In this article, the effects of thermo-oxidative aging on the dielectric properties of epoxy resin are investigated at 180 °C under different durations. In the early stage of aging (0–168 h), the dielectric properties of epoxy resin are slightly improved, which are characterized by the reduction of dielectric loss and conductivity and the slightly enhancement of breakdown strength. These are attributed to the molecular rearrangement and postcuring reactions inside the epoxy resin, as evidenced by the improved glass transition temperature. With the continuous increase of thermal aging time, oxidative decomposition and scission reactions start to dominate. The cross-linked network of epoxy resin is gradually destroyed, leading to the increase of carrier quantity and the reduction of trap energy level and density. The dielectric polarization and charge injection are intensified, while the partial discharge initiation voltage (PDIV) and breakdown strength are decreased significantly. After aging for 1440 h, the conductivity could be increased by 59.64%, and the breakdown strength is decreased by 18.14%. The insulation performance of epoxy resin is determined by the competition results of the molecular rearrangement, postcuring, and oxidative cleavage reactions during thermal aging, which could provide a theoretical basis for the aging assessment of epoxy resin for high-voltage applications.","PeriodicalId":13247,"journal":{"name":"IEEE Transactions on Dielectrics and Electrical Insulation","volume":"32 1","pages":"254-262"},"PeriodicalIF":2.9,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143106402","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":"Acoustic Emission and Propagation Characteristics of Metal Particles in GIS","authors":"Hao Liu;Wei-Xing Han;Zhen-Xing Fan;Ji-Hang Sun;Wei-Qi Qin;Xiang-Dong Liao;Si-Han Wang;Guo-Ming Ma","doi":"10.1109/TDEI.2024.3499895","DOIUrl":"https://doi.org/10.1109/TDEI.2024.3499895","url":null,"abstract":"Metal particle pollution was one of the significant factors that endangered the reliability of the gas-insulated switchgears (GISs). The detection of metal particles in GIS was crucial for ensuring the safe operation of GIS. This article established a calculation model for the cut-off frequency of acoustic emission (AE) generated by the metal particle collision with the GIS enclosure. The effects of metal particle materials, the Gaussian equivalent radius, and the bounce heights on the cut-off frequency of the AE signal were obtained. Through the AE measurement experiments of metal particle colliding with an aluminum plate, the accuracy of the cut-off frequency calculation model was verified. Besides, the experiment confirmed that the propagation mode of the AE signal on GIS enclosure was primarily the S0 mode Lamb wave. The attenuation of the AE signal was analyzed. The geometric attenuation and the energy loss attenuation were determined as the primary attenuation processes. A calculation model for the attenuation of AE signal was established. Based on this, the variation of the cut-off frequency after propagation on the GIS enclosure was clarified. The AE and propagation characteristic proposed in this article provided guidance for optimizing the frequency band of ultrasonic sensors and setting up the measurement points.","PeriodicalId":13247,"journal":{"name":"IEEE Transactions on Dielectrics and Electrical Insulation","volume":"32 1","pages":"20-27"},"PeriodicalIF":2.9,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143106412","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 Insulating Oil Type on Double Electric Layer at Oil-Paper Interface","authors":"Lu Gao;Yuqi Chen;Zepeng Lv;Jun Zhou;Kai Wu","doi":"10.1109/TDEI.2024.3496613","DOIUrl":"https://doi.org/10.1109/TDEI.2024.3496613","url":null,"abstract":"The oil-paper insulation system is the most frequently used insulation in transformers. For a long time, mineral oil has been the predominant choice due to its cost-effectiveness and commendable insulation performance, but it still has the disadvantages of low ignition point and low biodegradation rate. Vegetable insulating oil, as an environmentally friendly liquid dielectric with a high ignition point, is considered a promising substitute for mineral insulating oil. Our previous research found that the electric double layer (EDL) at the oil-paper interface hinders the charge transport and cause extra charge accumulation at the interface under dc stress, but there is still a lack of comparative studies on EDL involving various types of insulating oils. Employing Kelvin probe force microscopy (KPFM) and first-principles calculation, the charge distribution of EDL at the oil-paper interface is investigated in this work. The charge distribution of EDL at the oil-paper interface shows that negative charges gather on the insulating paper surface and positive charges diffuse in the insulating oil, and it is derived from the electron affinity discrepancy between the insulating oil and paper. In contrast to mineral oil, which is composed of diverse hydrocarbons, the molecular composition of vegetable oil closely resembles cellulose. Therefore, vegetable oil has a closer electron affinity to cellulose paper than mineral oils, which causes fewer negative charges to gather on the insulating paper surface, thereby weakening the effect of interface barrier and reducing the interface charge accumulation under dc stress, which is beneficial to the operation stability of transformers.","PeriodicalId":13247,"journal":{"name":"IEEE Transactions on Dielectrics and Electrical Insulation","volume":"32 3","pages":"1484-1491"},"PeriodicalIF":2.9,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144205935","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 Thermodynamic Evaluation of Various Cu-Doped ZIF-8 Ratios for SF6 Catalysis","authors":"Fuping Zeng;Kexin Zhu;Langlang Lv;Guangzhi Chen;Hua Jiang;Zichun Xue;Ju Tang","doi":"10.1109/TDEI.2024.3495588","DOIUrl":"https://doi.org/10.1109/TDEI.2024.3495588","url":null,"abstract":"SF6 is a greenhouse gas with strong greenhouse effect. How to rationally deal with waste SF6 has become an extensive research topic for scholars at home and abroad. Studies have shown that ZIF-8 has certain superiority as a catalyst, while metal doping in ZIF-8 may promote its catalytic ability. In this article, the undoped ZIF-8 model and the Cu-doped ZIF-8 model (Zn:Cu =1:5; Zn:Cu =3:3) were constructed, and the most stable adsorption structures of SF6 at three typical sites were obtained based on density-functional theory (DFT), with the 6-membered ring (6MR) window as the optimal adsorption site. The stable adsorption energy was the largest in the Zn:Cu =5:1 doped model (−98.352 kcal/mol), and during the adsorption process, the SF6 molecular bond lengths changed most drastically, and even the bond breaking phenomenon appeared. The catalytic ability of the Zn:Cu =3:3 doping model was in between that of the ZIF-8 and Zn:Cu =1:5 doping models. The results of the Mulliken charge transfer and the HOMO-LUMO energy level showed that in the Zn:Cu =5:1 doping model, the Cu atom can both transfer a large number of electrons (−0.606 e) to SF6 and enhance the ability of Zn atoms to lose electrons, effectively weakening the S-F bond strength of SF6 gas molecules and thus promoting SF6 gas molecule catalysis. The highest occupied molecular orbital (HOMO) wave function in the system is mainly distributed around the doped Cu atoms, the energy gap is significantly reduced, and the catalyst reactivity is enhanced.","PeriodicalId":13247,"journal":{"name":"IEEE Transactions on Dielectrics and Electrical Insulation","volume":"32 1","pages":"408-415"},"PeriodicalIF":2.9,"publicationDate":"2024-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143106360","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":"Cumulative Effect on Properties of Transformer Insulating Paper Under Multiple Short-Circuit Impacts","authors":"Huaze Sui;Peng Li;Ke Wang;Zhengyu Xu;Linda Li;Zuoxian Wang;Shuqi Zhang;Zhigang Zhao;Yuwei Zhong","doi":"10.1109/TDEI.2024.3495582","DOIUrl":"https://doi.org/10.1109/TDEI.2024.3495582","url":null,"abstract":"The insulating paper for transformer windings is an essential component in power transformers, serving the purpose of electrical insulation and mechanical support. The stability of the mechanical properties of insulating paper determines the reliable operation of the transformer. The cumulative effect properties of insulating paper under multiple short-circuit impacts remain unclear. In this article, a dynamic short-circuit force platform is built, which can generate impact forces with a transient component at 50 Hz to simulate real short-circuit forces. Cumulative plastic deformation of insulating paper under different conditions, such as the magnitude of short-circuit force, degree of aging, type of short circuit, and number of short-circuit occurrences, is obtained. The results indicate that the cumulative deformation of insulating paper is positively correlated with the magnitude of short-circuit force, with a maximum difference of 114.05%. The cumulative deformation of insulating paper exhibits a growth-saturation characteristic with increasing short-circuit occurrences, showing a saturation hysteresis effect, and the mathematical model conforms to the power function relationship. The cumulative deformation is positively correlated with the degree of aging, with a maximum increase of 202.78%. For aged insulating paper, the cumulative deformations caused by long-interval short circuits are greater than those caused by short-interval short circuits, with a maximum difference of 15.40%. The algorithm model of the equivalent relationship between short-circuit impacts with different magnitudes is proposed. The elastic modulus of insulating paper increases with the raising amplitude of short-circuit forces and decreases with the deepening of aging. This study demonstrates the cumulative effect properties of transformer insulating paper under multiple short-circuit impacts, which supports the calculation of transformer short-circuit dynamic response and differentiation assessment of transformer short-circuit withstand capability under various conditions.","PeriodicalId":13247,"journal":{"name":"IEEE Transactions on Dielectrics and Electrical Insulation","volume":"32 3","pages":"1668-1678"},"PeriodicalIF":2.9,"publicationDate":"2024-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144206007","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}