Article
Engineering, Electrical & Electronic
Jin Li, Yuhuai Wang, Xiaohui Duan, Jianwei Wei, Yaxiang Wang, Hucheng Liang, Boxue Du
Summary: In this article, the surface charge distribution and flashover characteristics of epoxy basin insulators in a down-sized dc-gas-insulated switchgear were studied under ac-dc composite voltage. The results indicated that higher composite voltage amplitude led to more heteropolar charges on the surface of the insulator, which tended to diffuse towards the central high-voltage electrode. Higher prestressing resulted in a decline in the ac component but an increase in the absolute amplitude of the flashover voltage. Direct ramp voltage stressing showed higher flashover voltage compared to prestressing. The surface modification of the insulators through direct fluorination improved the surface charge distribution and flashover voltage.
IEEE TRANSACTIONS ON DIELECTRICS AND ELECTRICAL INSULATION
(2023)
Article
Physics, Applied
Pu Han, Zijun Pan, Shiyi Mao, Yuhan Ye, Ju Tang, Cheng Pan
Summary: Charge accumulation at the insulator surface can significantly change the electric field distribution and cause unpredictable flashover under DC voltage. This study proposed a method to judge the moment approaching flashover and investigated the dynamic distributions of surface charges, including the charge distribution approaching flashover occurrence. The analysis of flashover on insulators coated in SiC/epoxy revealed a reversal of charge polarity during voltage rising and a relationship between charge distribution approaching flashover and flashover voltage, where an increase in SiC content resulted in greater charge accumulation and enhanced flashover voltage through weakening the electric field.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2023)
Article
Chemistry, Multidisciplinary
Jun Xie, Chaoxuan Xiao, Shuai Shao, Qijun Duan, Qing Xie, Fangcheng Lu
Summary: Doping bismuth ferrite nanoparticles can improve the flashover voltage of epoxy resin composites, with La + Cr elements co-doped composites showing higher flashover voltage. Additionally, appropriately reducing the surface charge dissipation rate of epoxy resin composites can increase the flashover voltage.
Article
Physics, Applied
Bo Qi, Zhuodong Yang, Xiao Yang, Meng Huang, Chunjia Gao, Yi Zhang, Yuan Luo, Licheng Lu, Chengrong Li
Summary: Epoxy post-insulator is a crucial component in SF6 gas-insulated DC wall bushing and plays an irreplaceable role in high voltage direct current transmission projects. Flashovers occur frequently on the post-insulators due to the presence of numerous tiny metal particles, which alter the insulation state of the surface. However, the relationship between the microstructure of the material and the macroscopic electrical properties during flashovers remains controversial. To investigate the impact of particles on flashover characteristics, particles generated from wear of the spring in the DC wall bushing were selected. The study measured the surface potential decay and the DC flashover voltage of epoxy attached with particles.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2023)
Article
Engineering, Electrical & Electronic
Zijun Pan, Cheng Pan, Ju Tang, Boli Hu, Yi Luo, Yuriy Serdyuk
Summary: This article investigates the dissipation of predeposited surface charges on SiC/epoxy coated insulators. Similar to Part I, the analysis considers a system of finger-shaped metallic electrodes on flat material samples with different types of material precharging. The study examines two cases based on different types of electrode-sample contacts as well as surface charging by external corona. The results show that the rate of charge dissipation is influenced by the content of SiC filler in the coating material.
IEEE TRANSACTIONS ON DIELECTRICS AND ELECTRICAL INSULATION
(2022)
Correction
Engineering, Electrical & Electronic
Muhammad Zeeshan Khan, Aurang Zaib, Asim Khan, Muhammad Arshad Shehzad Hassan, Umar Farooq, Zahir Javed Paracha
Summary: There was a spelling error in the name of one of the co-authors in the original version of the article, which has been corrected by publishing a correction article. The original article has been updated to reflect the correct name.
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
(2021)
Article
Engineering, Electrical & Electronic
Inzamam Ul Haq, Feipeng Wang, Shakeel Akram, Yuyang Yan
Summary: The effect of ion beam treatment on surface flashover characteristics of epoxy is evaluated and explored. The results show that ion beam treatment can enhance the flashover properties of epoxy by increasing the flashover voltage, changing the physicochemical characteristics, accelerating surface charge decay, reducing surface trap depth, increasing surface conductivity, and promoting charge migration and transport.
IEEE TRANSACTIONS ON DIELECTRICS AND ELECTRICAL INSULATION
(2022)
Article
Physics, Applied
Zhengyong Huang, Yingfan Zhang, Haohuan Wang, Jian Li
Summary: This paper investigates the use of oriented hBN composites with anisotropic thermal conductivity to improve electrical resistivity-temperature characteristics and inhibit the occurrence of DC surface flashover under temperature gradient. The study shows that the out-of-plane oriented hBN composite exhibits better electrical resistivity-temperature characteristics compared to polymer filled with ceramic particles. The results suggest that the least rise in carrier mobility and electric field intensity near the GND electrode is the main factor in inhibiting the occurrence of DC surface flashover of the oriented hBN composites at high temperatures.
APPLIED PHYSICS LETTERS
(2023)
Article
Engineering, Electrical & Electronic
Lu Fan, Yi Yin, Yalin Wang
Summary: An online surface potential measurement method is proposed and verified in this article to explore the dc flashover characteristics and evaluate the dc flashover resistance of epoxy resin. The results show that positive and negative flashover exhibit different surface potential evolution characteristics, with positive flashover being more severe than negative flashover.
IEEE TRANSACTIONS ON DIELECTRICS AND ELECTRICAL INSULATION
(2022)
Article
Engineering, Electrical & Electronic
Zijun Pan, Cheng Pan, Ju Tang, Boli Hu, Yi Luo, Yuriy Serdyuk
Summary: This study investigated the surface charge accumulation on silicon carbide (SiC)/epoxy coatings with different contents of SiC filler (3%, 5%, 7%, and 10%). The results showed that different patterns of charge distribution appeared on the material surface depending on the contact type, charging duration, and filler content.
IEEE TRANSACTIONS ON DIELECTRICS AND ELECTRICAL INSULATION
(2022)
Article
Engineering, Electrical & Electronic
Bo Qi, Zhuodong Yang, Xiao Yang, Chunjia Gao, Licheng Lu, Yi Zhang, Li Li, Caixin Sun, Chengrong Li
Summary: This article investigates the flashover characteristics of epoxy samples in SF6 gas in DC wall bushing and analyzes the flashover process through surface charge distribution measurement and electric field computation.
IEEE TRANSACTIONS ON DIELECTRICS AND ELECTRICAL INSULATION
(2022)
Article
Engineering, Electrical & Electronic
Zhenlian An, Jingpeng Sun, Yong Yang, Fang Liu, Xuguang Liu
Summary: The direct fluorination process significantly improves the dc flashover performance of gas insulated switchgear (GIS) by increasing the flashover voltage and reducing voltage dispersion. The fluorination temperature has a significant impact on the enhancement of the flashover voltage. The improvement in flashover performance is mainly attributed to the increase in surface conduction, which suppresses surface charge accumulation.
IEEE TRANSACTIONS ON DIELECTRICS AND ELECTRICAL INSULATION
(2022)
Article
Physics, Applied
Jianyi Xue, Zhu Zhang, Lijian Ding, Junbo Deng, Guan-Jun Zhang
Summary: A graded conductivity coating method is proposed in this study, which can effectively suppress the randomly distributed surface charges on insulators, improving surface charge accumulation and electric field distribution to enhance DC flashover performance.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2021)
Review
Physics, Multidisciplinary
Shaocong Wu, Hao Xu, Xuanning Zhang, Yanyu Liang, Yuming Shao, Cong Wang, Youping Tu, Yongsheng Xu
Summary: This paper focuses on the surface flashover induced by solid-gas interface charge accumulation in DC GIL/GIS. The distribution of the electric field and its impact on flashover voltage are analyzed, along with the influence of metal particles on charge and surface flashover.
Article
Engineering, Electrical & Electronic
Bingbing Dong, Ben Wu, Zhizheng Wang, Xingliang Jiang
Summary: This paper analyzes the mechanical characteristics of local arc propagation on the surface of suspension insulators during AC and DC pollution flashover, and concludes that the propagation of the local arc mainly depends on the electrostatic force and thermal buoyancy. The effect of thermal buoyancy is more significant in DC arc wandering, and with the increase in altitude, the effect of thermal buoyancy also increases, leading to a decrease in flashover voltage of polluted insulators.
IET GENERATION TRANSMISSION & DISTRIBUTION
(2022)
Article
Energy & Fuels
Songyuan Li, Pengxian Song, Zhanpeng Wei, Xu Li, Qinghua Tang, Zhengzheng Meng, Ji Li, Songtao Liu, Yuhuai Wang, Jin Li
Summary: The complex structure of gas-insulated switchgear (GIS) cable terminals often leads to electric field concentration, which is a common fault position in high-voltage cable systems. Currently, there are differences in the frequency bands of sensors used in various partial discharge detection technologies, resulting in a low defect detection rate in GIS cable terminals. This paper proposes a comprehensive diagnosis scheme that integrates transient earth voltage (TEV), ultra-high frequency (UHF), high frequency (HF), and ultrasonic methods. The proposed scheme was applied to track and monitor two abnormal discharge defects in GIS terminals at two 220 kV substations in Tianjin, determining the type and phase sequence of the defects and using UHV for precise defect location and analysis. Through disassembly analysis and electric field simulation, the accuracy and effectiveness of the discharge detection and location method were verified.
Article
Engineering, Electrical & Electronic
Zhonglei Li, Heyu Wang, Boxue Du
Summary: This article examines the impact of poly cyclic aromatic compounds (PACs) on the electrical treeing of cross-linked polyethylene (XLPE) insulation in high voltage (HV) cables. The study finds that the inclusion of PACs in XLPE insulation inhibits the growth of electrical trees and reduces the amplitude of partial discharges (PDs) during treeing. Additionally, under cyclic temperature conditions, the growth of electrical trees in XLPE/PACs composites stagnates as the temperature decreases. The research suggests that PACs enhance the resistance of XLPE/PACs composites against electrical treeing.
IEEE TRANSACTIONS ON DIELECTRICS AND ELECTRICAL INSULATION
(2023)
Article
Engineering, Electrical & Electronic
Jin Li, Pengxiang Guo, Xiaoxiao Kong, Yifang Wang, Yong Yang, Fang Liu, Boxue Du
Summary: In this study, the effect of the curing accelerator Tris-(dimethylaminomethyl) phenol (DMP-30) content on the curing behavior and dielectric properties of DGEBA/MHHPA system was investigated. It was found that the accelerator content has a saturation effect on the dielectric properties, and excessive content leads to an increase in dielectric constant and loss, and a decrease in breakdown strength. The cured sample with 0.5% accelerator addition showed the best dielectric properties and the highest breakdown strength, indicating that the optimum accelerator content allows for a more rational curing crosslinking network.
IEEE TRANSACTIONS ON DIELECTRICS AND ELECTRICAL INSULATION
(2023)
Review
Biochemistry & Molecular Biology
Jin Li, Hein Htet Aung, Boxue Du
Summary: This paper introduces the curing kinetic models of anhydride-cured bisphenol-A epoxy resin, determines the primary curing regime, discusses the influences of curing regime on insulation performance, and investigates the relationship between curing regime and microstructure.
Article
Materials Science, Composites
Renyong Zhao, Yun Chen, Jin Li, Songtao Liu, Yuhuai Wang, Xiaoxiao Kong, Boxue Du
Summary: In this study, the L-shaped needle-wire electrode was used to simulate the coupling direction of mechanical stress and electric field in GFRP composites. The effects of equivalent tension and compression load on the electrical tree degradation of GFRP were obtained. It was found that both tension and compression load aggravated the electrical tree degradation, and the combined action of high temperature and high pressure and external mechanical load accelerated the degradation process.
COMPOSITES SCIENCE AND TECHNOLOGY
(2023)
Article
Engineering, Electrical & Electronic
Jin Li, Yufan Wang, Yuhuai Wang, Qinghua Tang, Pengxian Song, Hucheng Liang, Boxue Du
Summary: In this article, the electrical breakdown characteristics of epoxy/Al2O3 composites under different temperature gradients are tested, and a phase-field simulation model of epoxy/Al2O3 composites with needle-plate electrodes is established. The influences of particle aggregation states on the breakdown characteristics under temperature gradient are analyzed. The results indicate that the breakdown process is accelerated with the increase of temperature gradient, while the high content of Al2O3 particle, especially the aggregation near needle electrode, can suppress the electrical breakdown of the composites. Particle aggregation can change the development route of electrical tree channels and affect the overall breakdown time of composites.
IEEE TRANSACTIONS ON DIELECTRICS AND ELECTRICAL INSULATION
(2023)
Article
Engineering, Electrical & Electronic
Jin Li, Yuhuai Wang, Xiaohui Duan, Jianwei Wei, Yaxiang Wang, Hucheng Liang, Boxue Du
Summary: In this article, the surface charge distribution and flashover characteristics of epoxy basin insulators in a down-sized dc-gas-insulated switchgear were studied under ac-dc composite voltage. The results indicated that higher composite voltage amplitude led to more heteropolar charges on the surface of the insulator, which tended to diffuse towards the central high-voltage electrode. Higher prestressing resulted in a decline in the ac component but an increase in the absolute amplitude of the flashover voltage. Direct ramp voltage stressing showed higher flashover voltage compared to prestressing. The surface modification of the insulators through direct fluorination improved the surface charge distribution and flashover voltage.
IEEE TRANSACTIONS ON DIELECTRICS AND ELECTRICAL INSULATION
(2023)
Article
Physics, Applied
Jianan Dong, Boxue Du, Hucheng Liang, Hang Yao
Summary: This paper develops a multi-dimensional functionally graded material (MFGM) to improve the insulation performance of the epoxy insulator. Results show that the MFGM insulator has higher AC and DC flashover voltages compared to the uniform insulator, making it suitable for gas insulated switchgear in high voltage direct current systems.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2023)
Review
Engineering, Electrical & Electronic
Shuaibing Li, Binglei Cao, Jin Li, Yi Cui, Yongqiang Kang, Guangning Wu
Summary: Composited cable terminals are crucial for reliable power delivery in power supply systems. The changing operating conditions and various factors can lead to defects or failures, making condition monitoring and defect detection imperative. This review provides an overview of cable terminal condition assessment, including monitoring methods, defect detection approaches, and future research directions.
Article
Mechanics
Jin Li, Renyong Zhao, Yuhuai Wang, Yun Chen, Xiaoxiao Kong, Boxue Du
Summary: Glass fiber-reinforced epoxy composites (GFREC) are commonly used in electrical and electronic devices due to their lightweight, high strength, excellent insulation properties, and corrosion resistance. Researching the electrical degradation dynamics of GFREC is crucial in preventing insulation failure. In this study, composite samples were prepared using vacuum impregnation, and the morphology and statistical characteristics of electrical degradation were discussed. The results showed that electrical trees in GFREC develop towards the fiber side and grow rapidly along the interface, with interfacial orientation affecting tree growth. The electric field distribution and fiber orientations were found to be related to electrical degradation.
COMPOSITE STRUCTURES
(2023)
Article
Engineering, Electrical & Electronic
Boxue Du, Zhijun Guo, Hucheng Liang
Summary: This study experimentally investigates the breakdown mechanism of tri-post insulators under electromechanical coupling and explores the effects of external force, fixing mode, and defect location on the breakdown morphologies. The results show that initial defects can lead to partial discharges that develop into bursting breakdown, and mechanical stress distribution and defect location influence the breakdown morphology.
IEEE TRANSACTIONS ON DIELECTRICS AND ELECTRICAL INSULATION
(2023)
Article
Polymer Science
You Wu, Boxue Du, Zhonglei Li, Heyu Wang, Zhong Zheng
Summary: This paper focuses on using α-nucleating agents to modulate the heterogeneous mesoscopic structure of polypropylene insulation, which effectively improves its dielectric strength. Experimental results show that the addition of α-nucleating agents reduces spherocrystal size, increases density, and enhances electric field uniformity. Moreover, the increase in spherocrystal density inhibits electrical tree growth, leading to an increase in breakdown strength. Simulation results demonstrate that the difference in dielectric properties between crystal and amorphous regions triggers electric field distortion and insulating degradation.
Article
Computer Science, Information Systems
Mingyang Wang, Xuegong Yin, Yuhao Liu, Boxue Du, Congzhao Xue
Summary: This paper investigates the effects of high magnetic field on electrical treeing of silicone rubber (SiR). The experimental results show that high magnetic field makes it easier for electrical trees to initiate and spread. Moreover, when the direction of high magnetic field is perpendicular to that of electric field, a higher magnetic flux density leads to a larger accumulated damage area. The splitting of energy band structure and changes in polarization characteristics contribute to a lower interface barrier and more serious partial discharge in high magnetic field, weakening the resistance to electrical treeing. Based on the insulation degradation mechanism, SiR was modified by adding ferroferric oxide (Fe3O4) nanoparticles to improve its insulation performance in high magnetic field. A moderate addition amount of Fe3O4 nanoparticles is found to suppress electrical treeing by forming quantum dots and modifying polarization properties and partial discharge behavior. However, excessive addition of Fe3O4 nanoparticles has negative effects due to the magnetization of the nanocomposites.
Article
Computer Science, Information Systems
Mingyang Wang, Yao Zhang, Congzhao Xue, Boxue Du, Yunqi Xing
Summary: High magnetic field leads to premature insulation failure. Addition of different filler contents of ferroferric oxide (Fe3O4) nanoparticles improves the AC breakdown strength of silicone rubber (SiR) by 5.40% in 12 T magnetic field due to their ability to regulate dielectric polarization and partial discharge (PD) behavior. However, the magnetization of Fe3O4 nanoparticles decreases the DC breakdown strength by 3.33% with 2 wt% filler content in 12 T magnetic field. Fluorination treatment can enhance the DC breakdown strength of SiR/Fe3O4 nanocomposites by 8.84% in 12 T magnetic field by regulating surface traps. Adding an appropriate amount of ferromagnetic nanoparticles before fluorination can improve both AC and DC breakdown strength by 0.64% and 8.81% respectively in high magnetic field.
