IEEE Transactions on Dielectrics and Electrical Insulation最新文献

{"title":"Measurement and Analysis of Corona Current Pulses in Needle-Plate Air Gap Under Negative Switching Impulse Voltages","authors":"Xiangrui Meng;Tiebing Lu;Xuebao Li","doi":"10.1109/TDEI.2024.3461675","DOIUrl":"https://doi.org/10.1109/TDEI.2024.3461675","url":null,"abstract":"With the development of offshore wind power, the insulation reliability of converter equipment has been paid more attention. The metal protrusion of converter equipment will lead to corona discharge or even breakdown under negative switching impulse (SI) voltages. The study of corona current pulses under negative SI voltages will be helpful to the monitoring and location of insulation defects in converter equipment. In this article, the corona current pulses of needle-plate gap in air under negative SI voltages were investigated by experiments and theoretical calculations. The first current pulse has a large crest value and mostly occurs at the wavefront of negative SI voltages. The subsequent current pulses have a small crest value and mostly occur at the wave tail of negative SI voltages. The voltage-time delay of corona current pulses under negative SI voltages were obtained by experiment, and the effect of wavefront time and voltage amplitude on the average discharge voltage and average time delay of current pulses were analyzed. The average time delay of the first current pulse decreases and the average discharge voltage of the first current pulse increases as the amplitude of negative SI voltages increase. The calculation model of theoretical time delay of the first current pulse was established, and the theoretical voltage-time delay curves of the first current pulse were calculated. The influence of particle volume fraction and air humidity on the voltage-time delay of the first current pulse were investigated by theoretical calculations. The theoretical discharge voltage and theoretical time delay of the first current pulse increase slightly as the air humidity increases and decrease as the particle volume fraction increases.","PeriodicalId":13247,"journal":{"name":"IEEE Transactions on Dielectrics and Electrical Insulation","volume":"32 2","pages":"983-991"},"PeriodicalIF":2.9,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143761437","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 Segment Insulation Diagnosis Method of Power Cable Based on Attenuation Coefficient in Frequency Domain","authors":"Zhirong Tang;Kai Zhou;Yefei Xu;Pengfei Meng;Yuan Li;Hongzhou Zhang;Kuangyi Jiang","doi":"10.1109/TDEI.2024.3461680","DOIUrl":"https://doi.org/10.1109/TDEI.2024.3461680","url":null,"abstract":"In recent years, the frequency domain reflection (FDR) method has been widely used in power cable defect location detection. However, the FDR method only diagnoses the change of insulation state at the defect and ignores that of the cable body. Thus, based on the mathematical model of the reflected wave of the power cable, a method to diagnose the insulation state of each segment of the power cable by using the attenuation coefficient is proposed in this article. In the method, the reflection coefficient spectrum (RCS) of a power cable and the location of defects are obtained by the traditional FDR method, and the power cable is divided into several segments based on the location of defects. Then, the two-point interpolation fast Fourier transform (I2pFFT) algorithm is used to estimate the attenuation coefficient of each segment in the RCS. Theoretically, the value of the attenuation coefficient is a characteristic of the change of the dielectric constant of the cable, thus the insulation state of the power cable can be diagnosed by attenuation coefficient. Finally, the feasibility and validity of the proposed method are verified by simulation and field 2 km/27.5 kV cable, respectively. The experimental results show that the proposed method can effectively diagnose the insulation state of each segment of the power cable.","PeriodicalId":13247,"journal":{"name":"IEEE Transactions on Dielectrics and Electrical Insulation","volume":"32 2","pages":"717-724"},"PeriodicalIF":2.9,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143761463","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":"Multiparameter Weight Analysis and Comprehensive Performance Evaluation of EPDM Rubber Under Ultraviolet Environment","authors":"Wenhao Deng;Hao Feng;Hao Guo;Yongjie Nie;Guochang Li;Yuanwei Zhu;Shengtao Li;Yanhui Wei","doi":"10.1109/TDEI.2024.3460729","DOIUrl":"10.1109/TDEI.2024.3460729","url":null,"abstract":"With the implementation of the “double carbon” strategy, much attention has been paid to the development and utilization of clean and renewable energy, such as offshore wind energy. Ethylene propylene diene monomer (EPDM) cables are widely used in power transmission of offshore wind turbines due to its excellent electrical and mechanical properties. Ultraviolet (UV) radiation has a great destructive effect on cable insulation materials under marine conditions. First, the effects of UV radiation on the electrical and mechanical properties of EPDM were studied by artificial accelerated aging experiments. Furthermore, several parameters, such as breakdown strength and tensile strength, were analyzed, and the effect of UV radiation on the comprehensive properties of EPDM was analyzed. The results show that EPDM undergoes recrosslinking, oxidation, and degradation reaction in the process of UV radiation aging, resulting in varying degrees of changes in resistivity, dielectric properties, breakdown strength, tensile strength, and other parameters. The improved gray relation analysis (GRA) is used to further analyze that the comprehensive properties under UV radiation of EPDM decreased rapidly from 0 to 480 h, with a decrease of 27.67%, and the comprehensive properties of the samples remained stable with the extension of aging time. This work has an important guiding significance for the long-term reliability evaluation of cable insulation materials for offshore wind power.","PeriodicalId":13247,"journal":{"name":"IEEE Transactions on Dielectrics and Electrical Insulation","volume":"32 2","pages":"950-957"},"PeriodicalIF":2.9,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142261356","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":"Charge Injection Barrier at the Metal/Oil-Paper Insulated Interface Based on First Principles","authors":"Yuqi Chen;Dayou Liu;Mrutyunjay Maharana;Jiacheng Zhou;Kai Wu;Ricardo Albarracín Sánchez;Niharika Baruah","doi":"10.1109/TDEI.2024.3460731","DOIUrl":"10.1109/TDEI.2024.3460731","url":null,"abstract":"In order to elucidate the mechanism of charge injection from metal into insulators, a comparative study of charge injection in oil-paper systems is carried out using the first-principles calculation. In this work, the hole and electron injection barriers in the electronic structure of metal-dielectric and interface dipole are studied by using different interfaces, including metals such as aluminum and copper and dielectrics, such as mineral oil (MO), vegetable oil (VO), and cellulose kraft paper. The above interface was simulated by molecular dynamics and measured by density functional theory (DFT). The results show that the hole injection barrier is smaller than the electron injection barrier for all interfaces, which is in good agreement with the experimental results of insulation oil injection barrier measurement. Moreover, feasible dielectric models containing various chemical traps are measured.","PeriodicalId":13247,"journal":{"name":"IEEE Transactions on Dielectrics and Electrical Insulation","volume":"32 2","pages":"751-759"},"PeriodicalIF":2.9,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142261354","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":"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}