Tuning Epoxy for Medium Frequency Transformer Application: Resin Optimization and Characterization of Nanocomposites at High Temperature

Awais, Muhammad; Chen, Xiangrong; Dai, Chao; Meng, Fanbo; Paramane, Ashish; Tanaka, Yasuhiro

doi:10.1109/tdei.2021.009596

Cited by 17 publications

(10 citation statements)

References 21 publications

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“… Li et al (2020 ) studied the space charge characteristics of epoxy materials at high temperatures and high field strengths and found that the ionization of an unreacted curing agent and electrode charge injection are the main sources of space charge. Awais et al (2021) studied the epoxy composites suitable for high-frequency and high-temperature applications and found that the composite materials suitable for high-frequency and high-temperature environments can be obtained by controlling the stoichiometric ratio of epoxy and added nanofillers. Chillu et al (2020) studied the space charge injection threshold and dissipation properties of aluminum–epoxy nanocomposites.…”

Section: Introductionmentioning

confidence: 99%

Space Charge Dynamics in Epoxy Resins Under the Influence of a Long-Term High Electric Field at Various Temperatures

Zhang

Jin

et al. 2022

Front. Chem.

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As the main insulating material of an ultra-high voltage (UHV) resin impregnated paper (RIP) bushing, epoxy resin accumulates space charge under the DC voltage, which would affect the insulation properties of the bushing. In this article, the evolution of space charge accumulation and dissipation within the epoxy resin samples was measured under the influence of a long-term (24 h) electric field of 60 kV/mm at 40°, 60°, 80°, and 100°C. The experimental results show that the space charge transport in the epoxy sample was a long-time dynamic process. When the temperature was not greater than 60°C, only homocharge accumulation was observed within the samples, and the space charge distribution did not reach a stable state even after 24 h of voltage application. When the temperature was not lower than 80°C, the positive heterocharge accumulation was observed at the interface between cathode and epoxy. Through analysis by fitting and numerical simulation, it was verified that the positive heterocharge accumulation was caused by the limitation of the hole extraction, and the transport of holes within the samples obeyed the jump conductance model.

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Section: Introductionmentioning

confidence: 99%

Space Charge Dynamics in Epoxy Resins Under the Influence of a Long-Term High Electric Field at Various Temperatures

Zhang

Jin

et al. 2022

Front. Chem.

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“…The addition of suitable micro‐sized inorganic particles (Al 2 O 3 , BN, SiO 2 , and AlN), especially nitrides (BN and AlN) having high inherent thermal conductivity, can enhance the thermal conductivity of EPR‐based dielectrics 5,15–18 . Particularly, BN is found more suitable as AlN particles deteriorate with time due to oxidation 4 . However, microparticles increase the viscosity of the composite mixture, which is more vulnerable to voids and defects and hence degrades the dielectric breakdown strength.…”

Section: Introductionmentioning

confidence: 99%

“…Epoxy resin (EPR) based dielectrics are extensively considered as good insulation materials in electronic packaging, military and aerospace applications, electronic equipment, and power system due to their low cost and easy availability, easy processing, rigorous physiochemical properties, lightweight, and high insulation strength. [4][5][6] However, the dielectric insulation performance of EPR gets compromised under HF and HT due to its low thermal stability, making it unsuitable for HF and high voltage (HV) applications.…”

Section: Introductionmentioning

confidence: 99%

“…5,[15][16][17][18] Particularly, BN is found more suitable as AlN particles deteriorate with time due to oxidation. 4 However, microparticles increase the viscosity of the composite mixture, which is more vulnerable to voids and defects and hence degrades the dielectric breakdown strength. The nanoparticles can enhance the dielectric breakdown strength but do not possess the required thermal conductivity, on the other hand, as they produce extreme interfaces in the composite.…”

Section: Introductionmentioning

confidence: 99%

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Influence of dielectric barrier effect and thermally‐conductive network on thermal and electrical properties of epoxy under different frequencies and temperatures

Awais

Chen

Shi

et al. 2022

J of Applied Polymer Sci

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Epoxy resin (EPR) insulations play a vital role in the insulation of modern power electronic equipment owing to their excellent dielectric properties.However, due to the high-power density and miniaturization of power equipment which causes high heat fluxes under high voltage and high-frequency stresses, EPR with good thermal and insulation properties is urgently needed.In this study, the polydopamine functionalized micro-BN and core-shell nano TiO 2 -SiO 2 particles are dispersed in EPR to simultaneously improve thermal and dielectric insulation properties. It is revealed that the addition of micronano particles significantly improves the thermal and dielectric performance. Particularly, the high thermal conductivity of micro-BN and the dielectric barrier effect due to the core-shell structure of nano TiO 2 -SiO 2 are the main reasons for improved thermal and dielectric insulation performance, respectively.The EPR composite containing 3 wt% of micro-BN and 1 wt% of nano TiO 2 -SiO 2 exhibits the optimal performance with 0.49 W/mK thermal conductivity and the highest dielectric strength among all the samples, that is, 60.61 kV/ mm even at 10 kHz and 90 C. This study found that the crucial factors are the surface encapsulation, weight percent, and homogeneous dispersion of particles in EPR, the dielectric barrier effect, thermal conductivity, and the mismatch between the dielectric constant of EPR and particles. This study proposes the optimal weight percent of suitable micro-nano particles for EPR to produce suitable composites for high-frequency and high-temperature applications.

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“…Epoxy resin has many advantages, e.g., high insulation strength, good chemical properties, and excellent environmental adaptability [ 1 , 2 , 3 , 4 , 5 , 6 , 7 ]. It is widely used in electrical equipment as a packaging and pouring material.…”

Section: Introductionmentioning

confidence: 99%

Terahertz-Based Method for Accurate Characterization of Early Water Absorption Properties of Epoxy Resins and Rapid Detection of Water Absorption

Dong¹,

Liu²,

Cao³

et al. 2021

Polymers

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Moisture is detrimental to the performance of epoxy resin material for electrical equipment in long-term operation and insulation. Therefore, moisture absorption is one of the critical indicators for insulation of the material. However, some relevant test methods, e.g., the direct weighing method, are time-consuming, and it usually takes months to complete a test. For this, it is necessary to have some modification to save the test time. Firstly, the study analyzes the present prediction method (according to ISO 62:2008). Under the same accuracy, the time required is reduced from 104 days to 71 days. Subsequently, the Langmuir curve-fitting method for water absorption of epoxy resin is analyzed, and the initial values of diffusion coefficient, bonding coefficient, and de-bonding coefficient are determined based on the results of molecular simulation, relevant experiment, and literature review. With the optimized prediction model, it takes only 1.5 days (reduced by 98% as compared with the standard prediction method) to determine the moisture absorbability. Then, the factors influencing the prediction accuracy are discussed. The results have shown that the fluctuation of balance at the initial stage will affect the test precision significantly. Accordingly, this study proposes a quantitative characterization method for initial trace moisture based on the terahertz method, by which the trace moisture in epoxy resin is represented precisely through the established terahertz time-domain spectroscopy system. When this method is used to predict the moisture absorbability, the experimental time may be further shortened by 33% to 1 day. For the whole water absorption cycle curve, the error is less than 5%.

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Tuning Epoxy for Medium Frequency Transformer Application: Resin Optimization and Characterization of Nanocomposites at High Temperature

Cited by 17 publications

References 21 publications

Space Charge Dynamics in Epoxy Resins Under the Influence of a Long-Term High Electric Field at Various Temperatures

Space Charge Dynamics in Epoxy Resins Under the Influence of a Long-Term High Electric Field at Various Temperatures

Influence of dielectric barrier effect and thermally‐conductive network on thermal and electrical properties of epoxy under different frequencies and temperatures

Terahertz-Based Method for Accurate Characterization of Early Water Absorption Properties of Epoxy Resins and Rapid Detection of Water Absorption

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