IEEE TRANSACTIONS ON DIELECTRICS AND ELECTRICAL INSULATION
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2024
·
IF 2.9
Qi Li,Boxue Du,WenBo Zhu,Xiaoxiao Kong
In this article, a simulation model of 110 kV cable termination based on COMSOL is established, and electro thermal coupling characteristics at different temperatures are simulated. Obvious uneven thermal stress distribution inside the termination is found at temperatures below −20 ∘ C, due to the difference in thermal expansion coefficients between different materials. Stress concentration at the interface between the metal insert and epoxy resin occurs. Tensile stress along the direction of the electric field in the epoxy increases as the temperature decreases, with a maximum value of 66.7 MPa at −40 ∘ C. The electrical treeing and partial discharge (PD) characteristics are investigated in epoxy resin under various thermal stress conditions. It is found that the electrical tree growth is accelerated under low temperatures, which is attributed to the increase in thermal stress and decrease in the toughness of the epoxy bushing. In such circumstances, the electrical tree growth rate is greatly increased, frequently accompanied by a sudden enhancement in PDs and expansion of deterioration channels, which is proved by a phase field model considering the induced thermal stress.
研究领域:
电气工程
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材料科学
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产品关联
DOI
高影响因子
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
·
2024
·Vol. 26
·期 7
·6429-6435
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IF 2.9
Yaru Zhang,Wenjia Zhang,Shixun Hu,Juan Li,Mingti Wang,Qi Zhang,Hao Yuan,Changlong Yang,Qi Li,Jinliang He
The electrical tree in grafted polypropylene (PP) is inhibited compared with that of pure PP. To understand the free radicals that are generated during the treeing process, we study the electron paramagnetic resonance (EPR) spectra. Additionally, to provide a clearer explanation of the suppression of electrical trees, this research uses electroluminescence (EL) and excitation computation. These methods help us to observe the movement of electrons and to understand the geometric and electronic structures involved. In pure PP, the energy required to excite the electrons is approximately the same as the band gap of PP while electrons are easier to be excited in grafted PP than in pure PP, because the band gap is narrower. As a result, though the electrical tree length is shorter in PP-g-MMA, the EPR signal is more intense because of the uneven distribution of electrons.
研究领域:
材料科学
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电气工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
POLYMER DEGRADATION AND STABILITY
·
2023
·
IF 5.9
Xiaoxing Zhang,Hui Lin,Yiran Hu,Dalin Ding,Fujin Cai,Yunjian Wu
Epoxy resin is one of the most commonly used insulating materials for electricians. Nevertheless, the emergence of localized damage or subtle microcracks within the material poses a formidable challenge in terms of detection and subsequent repair. The safe operation of power equipment is seriously jeopardized. In this study, driven by the need for self-healing insulating materials in power equipment applications, the successful synthesis of high-performance epoxy insulating materials featuring varying disulfide bond contents was achieved. Mechanical properties such as tensile strength and elongation at the break of epoxy insulations are enhanced by small amounts of disulfide bond. While an elevated content of disulfide bond diminishes the heat resistance and electrical characteristics of epoxy insulating materials, it is noteworthy that the prerequisites of epoxy resins for electrical applications remain adequately fulfilled. The results of the mechanical damage Self-healing test showed that the optimal repair efficiency reached 81.23 %. Simultaneously, the differentiation of electric tree branches can be inhibited by a disulfide bond. The diminishment of electric tree damage extent within epoxy resin is optimized, and the impairments of electric trees are repaired. Grounded in a disulfide bond, the viability of utilizing self-healing epoxy resins as insulating materials for electrical equipment is substantiated in this paper.
研究领域:
材料科学
·
电气工程
✓ 已验证
产品关联
DOI
高影响因子
Journal of Materials Chemistry C
·
2020
·Vol. 8
·期 18
·6025-6033
·
IF 7.059
Jiaye Xie,Lei Gao,Jun Hu,Qi Li,Jinliang He
Electrical treeing is regarded as the major factor that results in electrical damage of polymer insulation and thus shortens the lifetime and compromises the reliability of electrical power systems and power electronics. In bulk thermoset polymers, which are widely used as electrical insulation, self-healing of the electrical damage caused by treeing has rarely been reported. In this work, self-healing of electrical damage in a thermoset polymer, i.e., epoxy, is achieved through an anionic polymerization-based microcapsule approach. The epoxy matrix is modified with 2-ethyl-4-methylimidazole that initiates anionic polymerization of the healing agents and thereby repairs the electrical tree channels. The anionic polymerization is designed to be favoured in a moderate temperature range that matches with the working condition of many polymer insulation materials in electrical power systems, eliminating the need of additional stimuli that are usually required to trigger the healing reaction. It is substantialized that the electrical tree channels in the self-healing epoxy are re-built once they encounter and rupture the microcapsules, and the dielectric properties are completely recovered. This design of a self-healing material offers new possibilities for smart dielectrics that are needed in future electrical power systems and power electronics with a longer service lifetime and improved reliability.
研究领域:
材料科学
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电气工程
✓ 已验证
产品关联
DOI
高影响因子
Materials
·
2021
·Vol. 14
·期 8
·1811
·
IF 3.623
Peng Zhang,Xuan Wang,Jiaming Yang,Yongqi Zhang
Blending polypropylene (PP) with thermoplastic elastomer SEBS can effectively improve the mechanical toughness of PP, thus leading to the promise of SEBS/PP as the primary insulation material for high voltage alternating current (HVAC) cables. However, the growth of electrical trees during cable operation limits the application of SEBS/PP. In this paper, acetylation reaction is used to construct acetophenone group at the end of the benzene ring on SEBS so that it has the effect of both a toughening agent and a voltage stabilizer. Then PP was melt blended with acetylated SEBS (Ac-SEBS), and the effects of Ac-SEBS on the mechanical properties, electrical tree resistance, alternating current (AC) breakdown strength, and dielectric spectrum of PP were mainly investigated with reference to PP and SEBS/PP. The results showed that Ac-SEBS with 30% content could enhance the mechanical toughness of PP and improve the electrical tree resistance and AC breakdown strength of SEBS/PP. The AC breakdown field strength of Ac-SEBS/PP reached the highest when the acetylation level was 4.6%, which was 9.2% higher than that of SEBS/PP. At this time, Ac-SEBS was also able to absorb high-energy electrons through the keto-enol interchange isomerization reaction, which inhibited the initiation and growth of electric trees and caused the development of electric dendrites in a jungle-like manner. Moreover, the dielectric loss factor of AC-SEBS/PP in power frequency is within the allowable range of industry. Therefore, Ac-SEBS/PP is expected to be applied to HVAC cables, thus further improving the efficiency of HVAC power transmission.
研究领域:
材料科学
·
电气工程
✓ 已验证
DOI
高影响因子
High Voltage
·
2024
·
IF 4.4
Yunxiao Zhang,Wenxin Lin,Yuanxiang Zhou,Weiwei Xing,Jiayu Cheng,Chenyuan Teng
Electrical tree degradation is one of the main causes of insulation failure in high-frequency transformers. Electrical tree degradation is studied on pure epoxy resin (EP) and MgO/EP composites at frequencies ranging from 50 Hz to 130 kHz. The results show that the tree initiation voltage of EP decreases, while the growth rate and the expansion coefficient increase with frequency. Moreover, the bubble phenomenon at high frequencies in EP composites is discussed. Combined with trap distribution characteristics within the material, the intrinsic mechanism of epoxy composites to inhibit the growth of the electrical tree at different frequencies is discussed. It can be concluded that more deep traps and blocking effect are introduced by doping nano-MgO into EP bulks, which can improve the electrical tree resistance performance of EP composites in a wide frequency range.
研究领域:
电气工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF POLYMER RESEARCH
·
2022
·Vol. 29
·期 11
·1-11
·
IF 3.061
Li Mingyue,Chen Yidong,Xu Qingwen,Chen Yilin,Ren Xiancheng,Zhou Kai
Underground power cables are prone to electrical tree aging and additives loss due to the harsh working environment. In this work, the thermal aged cross-linked polyethylene (XLPE) cables were restored by injecting a newly synthesized voltage stabilizer containing hydrolyzable siloxane groups. The voltage stabilizer functionalized siloxane groups greatly enhanced the electrical tree initiation voltage, significantly reduced the direct current (DC) conductivity and dielectric loss factor. The results of scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS) indicated that the voltage stabilizer molecules were distributed in the electrical tree channels of the restored cables. After secondary thermal aging at 150 °C for 360 h, the characteristic electrical tree initiation voltage of the restored cable reached 12.10 kV, which was 66.90% higher than that of the unrestored cable. This indicated that the migration of voltage stabilizers could be inhibited by introducing hydrolyzable groups. This investigation provided a new approach to improve the migration resistance of the voltage stabilizer and the inhibitory effect of the rejuvenation liquid on the electrical tree.
研究领域:
材料科学
·
电气工程
✓ 已验证
产品关联
DOI
高影响因子
Journal of Materials Chemistry A
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2024
·
IF 10.7
Xueying Liu,Weibo Li,Yingjie Jiang,Nanying Ning,Ming Tian
Dielectric elastomer generators (DEGs) based on silicone rubber composites have received considerable attention in recent years. However, the addition of traditional rigid dielectric fillers not only increases the modulus of composites but also leads to interface debonding between the filler and elastomer matrix under high stretching conditions, thereby limiting the energy harvesting performance. Here, gel-like ester group grafted butadiene rubber (GEBR) with a relatively low modulus was synthesized and used as a “soft filler” to enhance energy harvesting performance of PMVS-based DE composites. The GEBR filler with a high concentration of polar groups could lead to an increase in the dielectric constant of GEBR/PMVS composites by the introduction of interfacial polarizability and the improvement of dipole polarizability. Most notably, compared with TiO2 as the rigid filler, the combination of GEBR's deformability under stretching and strong interfacial interaction between the GEBR filler and PMVS matrix could effectively prevent weak interface formation under high strain conditions, and thus hinder the propagation of electrical treeing. As a result, benefiting from the GEBR filler with a low modulus, 5 vol% GEBR/PMVS DEG exhibits an excellent maximal energy density (65.4 mJ g−1) and outstanding power conversion efficiency (38.4%), achieving a high energy density at relatively low input mechanical force. This study presents a pioneering methodology to fabricate high-performance all-organic DE composites for DEGs through designing a soft dielectric filler with exceptional deformability under stretching.
研究领域:
材料科学
·
能源技术
✓ 已验证
产品关联
DOI
高影响因子
POLYMER
·
2025
·
IF 4.5
Bo Zhu,Xu Sun,Yu Feng,Ji Liu,Xinyu Tao,Bo Yang
A microcapsule/XLPE composite material based on reversible Diels-Alder(DA) reaction was designed to solve the problem of electro-hydro hybrid tree aging in cross-linked polyethylene (XLPE) cables during long-term operation. Light-water dual-responsive microcapsules were prepared by in-situ polymerization using hyperbranched polysiloxane containing furan functional groups and linear polysiloxane containing furan and maleimide functional groups introduced by C C covalent bond as core materials and urea-formaldehyde resin as wall materials. A series of composites was prepared by regulating the doping concentration of microcapsules, and their insulation properties were tested. The effect of the doping content of microcapsules on the properties of materials was analyzed, and the multiple self-healing mechanism of microcapsule/XLPE composite was revealed. The results show that when the microcapsule doping concentration is 1 wt%, the composite material can self-heal while maintaining the intrinsic insulation performance of XLPE. Under the condition of thermal triggering, the dynamic reconstruction of the reversible bond enables the material to achieve dual repair of water tree and electrical tree damage, and maintains more than 80 % of the insulation performance after three times of damage-repair, which provides a new strategy for the intelligent design and life extension of high voltage cable insulation materials.
研究领域:
高分子材料科学
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电气绝缘工程
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功能复合材料
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智能材料
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电力电缆技术
✓ 已验证
产品关联
DOI
高影响因子
Polymers
·
2019
·Vol. 11
·期 1
·176
·
IF 3.164
Wei Dong,Xuan Wang,Bo Tian,Yuguang Liu,Zaixing Jiang,Zhigang Li,Wei Zhou
Aromatic voltage stabilizers can improve the dielectric properties of cross-linked polyethylene (XLPE); however, their poor compatibility with XLPE hinders their practical application. Improving the compatibility of aromatic voltage stabilizers with XLPE has, therefore, become a new research goal. Herein 1-(4-vinyloxy)phenylethenone (VPE) was prepared and characterized. It can be grafted onto polyethylene molecules during the cross-linking processes to promote stability of the aromatic voltage stabilizers in XLPE. Fourier transform infrared spectroscopy confirmed that VPE was successfully grafted onto XLPE, and effectively inhibited thermal migration. Thermogravimetric analysis showed that the grafted VPE/XLPE composite exhibits a better thermal stability than a VPE/PE blend composite. Evaluation of the electrical properties showed that the breakdown strength and electrical tree initiation voltage of the VPE/XLPE composite were increased by 15.5% and 39.6%, respectively, when compared to those of bare XLPE. After thermal aging, the breakdown strength and electrical tree initiation voltage of the VPE/XLPE composite were increased by 9.4% and 25.8%, respectively, in comparison to those of bare XLPE, which indicates that the grafted voltage stabilizer can effectively inhibit its migration and enhance the stability of the composite material.Keywords:cross-linked polyethylene;grafted voltage stabilizer;breakdown strength;electrical tree initiation voltage
研究领域:
材料科学
·
电气工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Materials Chemistry C
·
2023
·Vol. 11
·期 41
·14217-14225
·
IF 6.4
Potao Sun,Zeyan Shi,Wenxia Sima,Xinyu Tang,Tao Yuan,Ming Yang,Hang Xu,Zhaoping Li
Microscale damage, including cracks and electrical trees, is inevitably generated in the polymer insulation materials used in the packaging of power equipment and power electronic devices during long-term operation, which leads to premature insulation failure or even widespread power outages. Self-healing insulation materials are the most promising way to solve this problem. However, the mechanical/electrical strength or the dimensional stability of the materials could be sacrificed during the repair process, which has limited their application as insulation materials. In this study, we report an intrinsic self-healing epoxy resin based on reversible anthracene photodimerization (ISEP-RAP) that remains mechanically robust while ensuring efficient healing via a reversible reaction. The damaged area is decrosslinked by 254 nm UV and thermal excitation, which accelerates the molecular chain diffusion to the damaged area to fill and repair the damaged channels. The ISEP-RAP is recrosslinked by 365 nm UV to restore the mechanical and electrical properties after self-healing. Due to the combined action of the epoxy-amine permanent crosslinking sites and the anthracene reversible crosslinking sites, high crosslinked ISEP-RAP possesses excellent tensile and dielectric strength similar to that of standard epoxy resin and a lower permittivity constant. Importantly, the decrosslinked ISEP-RAP still possesses sufficiently high strength to keep the macrostructure unchanged. ISEP-RAP achieves high-efficiency, repeatable, non-contact intrinsic self-healing of scratches and electrical trees with whole-process dimensional stability. This work provides a new method for intrinsic self-healing in mechanically robust insulation materials to eliminate microdamage with repeatability, high reliability, and high efficiency.
研究领域:
材料科学
·
电气工程
✓ 已验证
产品关联
DOI
高影响因子
IEEE TRANSACTIONS ON DIELECTRICS AND ELECTRICAL INSULATION
·
2024
·
IF 2.9
Yongqiang Wang,Fengxiao Zhang,Yaqi Deng,Jing Shang
The introduction of micro- and nanoparticles is an important means to improve the electrical dendritic properties of epoxy resin (EP) composites. Aiming at the problem that the waste aramid powder generated during the production process of aramid fiber products is difficult to be effectively utilized, the paper adopts both dopamine modification and co-modification with dopamine and 2-(3,4-Epoxycyclohexyl)ethyltrimethoxysilane in the treatment of micrometer-sized aramid fiber powders. The untreated powder(AP), dopamine-modified powder(DAP), and co-modified powder(SDAP) were prepared into composite specimens with EP, and the trap properties, electrical trees initiation, and growth characteristics of the three specimens with different doping concentrations were investigated for the first time. Tests and analyses show that the powder inside AP/EP is mostly agglomerated and entangled, the shallow phenomenon of deep traps is serious, electrical trees properties have declined. With the increase of doping concentration, the energy level and density of deep traps of DAP/EP and SDAP/EP specimens increased, which helped to improve the initiation and growth characteristics of the electrical trees. The results of the study expanded the application forms of aramid products and provided new ideas and choices for the search of high quality fillers to improve the electrical dendrite properties of epoxy resins.
研究领域:
材料科学
·
电气工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）