scholarly journals Repair Performance of Self-Healing Microcapsule/Epoxy Resin Insulating Composite to Physical Damage

2019 ◽  
Vol 9 (19) ◽  
pp. 4098 ◽  
Author(s):  
Youyuan Wang ◽  
Yudong Li ◽  
Zhanxi Zhang ◽  
Haisen Zhao ◽  
Yanfang Zhang
Keyword(s):  
Epoxy Resin ◽  
Molecular Diffusion ◽  
Breakdown Strength ◽  
Mechanical Damage ◽  
Electrical Equipment ◽  
Physical Structure ◽  
Self Healing ◽  
Physical Damage ◽  
Repair Rate ◽  
Electrical Tree

Minor physical damage can reduce the insulation performance of epoxy resin, which seriously threatens the reliability of electrical equipment. In this paper, the epoxy resin insulating composite was prepared by a microcapsule system to achieve its self-healing goal. The repair performance to physical damage was analyzed by the tests of scratch, cross-section damage, electric tree, and breakdown strength. The results show that compared with pure epoxy resin, the composite has the obvious self-healing performance. For mechanical damage, the maximum repair rate of physical structure is 100%, and the breakdown strength can be restored to 83% of the original state. For electrical damage, microcapsule can not only attract the electrical tree and inhibit its propagation process, but also repair the tubules of electrical tree effectively. Moreover, the repair rate is fast, which meets the application requirements of epoxy resin insulating material. In addition, the repair behavior is dominated by capillarity and molecular diffusion on the defect surface. Furthermore, the electrical properties of repaired part are greatly affected by the characteristics of damage interface and repair product. In a word, the composite shows better repair performance to physical damage, which is conducive to improving the reliability of electrical insulating materials.

scholarly journals Effect of Doping Microcapsules on Typical Electrical Performances of Self-Healing Polyethylene Insulating Composite

2019 ◽  
Vol 9 (15) ◽  
pp. 3039 ◽  
Author(s):  
Youyuan Wang ◽  
Yudong Li ◽  
Zhanxi Zhang ◽  
Yanfang Zhang
Keyword(s):  
Space Charge ◽  
Structural Damage ◽  
Carrier Transport ◽  
Breakdown Strength ◽  
Mechanical Damage ◽  
Electrical Performance ◽  
Self Healing ◽  
Nucleation Effect ◽  
Electrical Tree ◽  
Effect Of Doping

Polyethylene cables, as important transmission equipment of modern power grid, would inevitably be slightly damaged, which seriously threatens the safety of the power supply. This paper has pioneered the preparation and typical performances of a self-healing polyethylene insulating composite. The self-healing performance to structural damage was verified by tests of electrical and mechanical damage. The effect mechanism of doping microcapsules on the electrical performance of polyethylene was emphatically analyzed. The results show that in appropriate conditions (such as 60 °C/30 min), the composite can not only repair the electrical tree and scratches, but also restore the insulation strength of damaged area. The effect of doping microcapsules on the electrical performances of polyethylene, such as breakdown strength, volumetric resistivity, dielectric properties, and space charge characteristics, are mainly related to impurity and the interface of microcapsule. Polarization and ionization of impurities can reduce the electrical performance of polyethylene. The interface not only improves the microstructure of polyethylene (such as how the heterogeneous nucleation effect increases the number of crystal regions, and the anchoring effect enhances the stability of amorphous regions), but also increases the charge traps. Moreover, the microstructure and charge trap can affect the characteristics of carrier transport, material polarization, and space charge accumulation, thus improving the electrical performance of polyethylene. In addition, the important electrical performance of the composite can meet the basic application requirements of polyethylene insulating material, which has good application prospects.

scholarly journals Preparation and Self-Repairing Properties of Urea Formaldehyde-Coated Epoxy Resin Microcapsules

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Xiaoxing Yan ◽  
Yijuan Chang ◽  
Xingyu Qian
Keyword(s):  
Epoxy Resin ◽  
Deposition Time ◽  
Urea Formaldehyde ◽  
Coverage Rate ◽  
Core Material ◽  
Self Healing ◽  
Mass Ratio ◽  
Repair Rate ◽  
The Core ◽  
Five Factors

Urea formaldehyde resin-coated epoxy resin microcapsules were prepared by two-step in situ polymerization. The effects of five factors on the yield, coverage rate, repair rate, and morphology of the microcapsules were investigated by five factors and four levels of orthogonal test. These five factors were the mass ratio of the core to the wall material (Wcore:Wwall), the mass ratio of the emulsifier to the core material (Wemulsifier:Wcore), stirring rate, deposition time, and mass ratio of the emulsifier solution to the core material (Wemulsifier solution:Wcore). The ideal technological level of microcapsule synthesis was determined. According to the results of the range and variance of yield, coverage rate, and repair rate, the comprehensive properties of microcapsules became ideal. At this time, the Wcore:Wwall was 0.8 : 1, Wemulsifier:Wcore was 1 : 100, stirring rate was 600 r/min, deposition time was 32 h, and Wemulsifier solution:Wcore was 8 : 1. When the concentration of microcapsules in the epoxy resin was 10.0%, the self-repair rate was the best and the repair rate was 114.77%. This study is expected to provide a reference value for the preparation of a microcapsule self-healing technology and lay a foundation for the subsequent development of self-healing materials.

scholarly journals Qualitative sensing of mechanical damage by a fluorogenic “click” reaction

2016 ◽  
Vol 52 (74) ◽  
pp. 11076-11079 ◽  
Author(s):  
Diana Döhler ◽  
Sravendra Rana ◽  
Harald Rupp ◽  
Henrik Bergmann ◽  
Shahed Behzadi ◽  
...  
Keyword(s):  
Click Reaction ◽  
Cycloaddition Reaction ◽  
Mechanical Damage ◽  
Self Healing ◽  
Physical Damage ◽  
Strong Fluorescence ◽  
Damage Sensing

A simple and unique damage-sensing tool mediated by a Cu(i)-catalyzed [3+2] cycloaddition reaction is reported, where a fluorogenic “click”-reaction highlights physical damage by a strong fluorescence increase accompanied by in situ monitoring of localized self-healing.

Radiated Electro-Magnetic Waves Caused by Electrical Tree Development in Epoxy Resin

2009 ◽  
Vol 129 (12) ◽  
pp. 915-921 ◽  
Author(s):  
Hideki Ueno ◽  
Takashi Nagamachi ◽  
Masaki Nakamura ◽  
Hiroshi Nakayama ◽  
Kunihiko Kakihana
Keyword(s):  
Epoxy Resin ◽  
Electrical Tree ◽  
Electro Magnetic ◽  
Tree Development ◽  
Magnetic Waves

scholarly journals The Development of Electrical Tree Discharge in Epoxy Resin Impregnated Paper Insulation

IEEE Access ◽  
2020 ◽  
Vol 8 ◽  
pp. 69522-69531
Author(s):  
Yongqiang Wang ◽  
Changhui Feng ◽  
Yu Luo
Keyword(s):  
Epoxy Resin ◽  
Electrical Tree ◽  
Paper Insulation

Investigation of space charge behavior in self-healing epoxy resin composites

2021 ◽  
Author(s):  
Muhammad Zeeshan khan ◽  
Muhammad Hamza Younes ◽  
Aurang Zaib ◽  
Umar Farooq ◽  
Asim khan ◽  
...  
Keyword(s):  
Space Charge ◽  
Epoxy Resin ◽  
Resin Composites ◽  
Self Healing ◽  
Epoxy Resin Composites

scholarly journals Application of the Gaussian Mixture Model to Classify Stages of Electrical Tree Growth in Epoxy Resin

Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2562
Author(s):  
Abdullahi Abubakar Mas’ud ◽  
Arunachalam Sundaram ◽  
Jorge Alfredo Ardila-Rey ◽  
Roger Schurch ◽  
Firdaus Muhammad-Sukki ◽  
...  
Keyword(s):  
Epoxy Resin ◽  
Gaussian Mixture Model ◽  
Mixture Model ◽  
Tree Growth ◽  
Asset Management ◽  
Gaussian Mixture ◽  
Growth Stages ◽  
Insulation Material ◽  
Electrical Tree ◽  
Electrical Trees

In high-voltage (HV) insulation, electrical trees are an important degradation phenomenon strongly linked to partial discharge (PD) activity. Their initiation and development have attracted the attention of the research community and better understanding and characterization of the phenomenon are needed. They are very damaging and develop through the insulation material forming a discharge conduction path. Therefore, it is important to adequately measure and characterize tree growth before it can lead to complete failure of the system. In this paper, the Gaussian mixture model (GMM) has been applied to cluster and classify the different growth stages of electrical trees in epoxy resin insulation. First, tree growth experiments were conducted, and PD data captured from the initial to breakdown stage of the tree growth in epoxy resin insulation. Second, the GMM was applied to categorize the different electrical tree stages into clusters. The results show that PD dynamics vary with different stress voltages and tree growth stages. The electrical tree patterns with shorter breakdown times had identical clusters throughout the degradation stages. The breakdown time can be a key factor in determining the degradation levels of PD patterns emanating from trees in epoxy resin. This is important in order to determine the severity of electrical treeing degradation, and, therefore, to perform efficient asset management. The novelty of the work presented in this paper is that for the first time the GMM has been applied for electrical tree growth classification and the optimal values for the hyperparameters, i.e., the number of clusters and the appropriate covariance structure, have been determined for the different electrical tree clusters.

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