Application feasibility of permittivity graded FGM (functionally graded materials) for gas‐insulated equipment

Shumiya, Hideki; Katō, K.; Ōkubo, H.

doi:10.1002/eej.20363

Cited by 10 publications

(3 citation statements)

References 8 publications

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“…New functional materials with graded permittivity have been developed in order to allow control of the electric field distribution [1]. However, there is no established method for measurement of the permittivity gradient, which hinders the practical use of the new materials.…”

Section: Introductionmentioning

confidence: 99%

Estimation of the location of dielectrics using a capacitor with widely spaced parallel electrodes and additional electrodes

Ohchi

Heigaku

Tokushima

et al. 2010

Electrical Engineering Japan

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SUMMARYWe have investigated the estimation of the location of a dielectric from the capacitance measured with widely spaced measurement electrodes provided with a shield and additional electrodes. In order to investigate the estimation method, a numerical technique was developed for calculating the capacitance between widely spaced measurement electrodes by finite element analysis. We discuss the new method for estimation of the locations of two dielectrics by using a capacitor with widely spaced parallel electrodes and additional electrodes.

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Section: Introductionmentioning

confidence: 99%

Estimation of the location of dielectrics using a capacitor with widely spaced parallel electrodes and additional electrodes

Ohchi

Heigaku

Tokushima

et al. 2010

Electrical Engineering Japan

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“…Recently, Okubo and others prepared epoxy composites with graded permittivity by applying centrifugal force, and investigated the electric field characteristics of FGM spacer. The results have showed that introduction of FGM insulator in gas insulated switchgear (GIS) equipment can effectively relax the concentration of electric filed stress around triple junction point [2][3][4][5].…”

Section: Introductionmentioning

confidence: 99%

Application of Functionally Graded Materials for Solid Insulator: Fabrication, Optimization Design, and Surface Flashover of Prototype Samples

Li¹,

Tian²,

Deng³

et al. 2013

AMM

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The applicability of functionally graded materials (FGM) for solid insulator of gas insulated switchgear (GIS) was investigated. First, a new fabrication method based on layer-by-layer casting technique was demonstrated to prepare FGM insulator possessing spatial distribution of dielectric constants. Then, electric field strength in the FGM spacer model was calculated and optimized by using finite element method (FEM). Three types of truncated cone spacers were fabricated according to the optimization results. Finally, surface flashover tests were performed under AC voltage and lightning impulse voltage applications. Results in both circumstances indicated an evident improvement of flashover voltage when FGM insulator was employed. As a result, we verified the fabrication technique and the applicability of FGM insulator for enhancement of insulation performance in GIS device.

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“…Hashmi and Dwivedi proposed a predictive model (HD Model) for evaluating the velocity and concentration of particles at different locations in a polymerizing fluid (curing polymer) under gravity or centrifugal force. [8][9][10] Shumiya and Kurimoto tried to prepare two 3-G composites (TiO 2 /epoxy and Al 2 O 3 /epoxy) for the application of a gas insulated switchgear; [11][12][13] Nigrawal and Chand discussed the distribution of permittivity in a carbon soot/ polyester graded composite. 14 These researches have pictured the great importance and feasible applications of 3-G composites based on polymer resin matrices, however some key and basic topics have not been studied, and consequently, it is difficult to develop a FG composite with expected performance.…”

Section: Introductionmentioning

confidence: 99%

Novel permittivity gradient carbon nanotubes/cyanate ester composites with high permittivity and extremely low dielectric loss

Liang

et al. 2011

J. Mater. Chem.

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Novel permittivity gradient (3-G) composites based on surface treated multi-walled carbon nanotubes (eMCNTs) and cyanate ester (CE) resin were successfully developed by the gravity sedimentation method. The composites consisting of original multi-walled carbon nanotubes (MCNTs) and CE resin, coded as MCNT/CE, were also prepared for comparison. Each composite was cut into three slices in the direction of thickness for evaluating the difference of dielectric properties over a wide frequency range from 1 to 10 9 Hz between the whole composites and their slices. Results show that the surface treatment of MCNTs is necessary to form 3-G composites because the good dispersion of nanotubes in the resin matrix and the attractive interfacial adhesion between nanotubes and the matrix are key aspects for guaranteeing the gradient distribution of the concentration of nanotubes in the composites. Note that two interesting phenomena were discovered. First, the whole composites show different conductive and dielectric properties from their slices, specifically, the percolation effect does not appear in either whole eMCNT/CE or MCNT/CE composites, while it can be observed in their slices. In addition, the percolation threshold of the eMCNT/CE slice is about 25% lower than that of the MCNT/ CE slice. Second, with regard to the whole composite and its slice with the same content of nanotubes, they have a similar dielectric constant, but the dielectric loss factor of the former is remarkably larger than that of the latter; these differences in properties are attributed to the different space distribution of the concentration of nanotubes between the whole composites and slices. These attractive features of eMCNT/CE composites suggest that the method proposed herein is a new approach to develop high performance 3-G composites, especially those with high dielectric constant and extremely low dielectric loss for cutting-edge industries.

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Application feasibility of permittivity graded FGM (functionally graded materials) for gas‐insulated equipment

Cited by 10 publications

References 8 publications

Estimation of the location of dielectrics using a capacitor with widely spaced parallel electrodes and additional electrodes

Estimation of the location of dielectrics using a capacitor with widely spaced parallel electrodes and additional electrodes

Application of Functionally Graded Materials for Solid Insulator: Fabrication, Optimization Design, and Surface Flashover of Prototype Samples

Novel permittivity gradient carbon nanotubes/cyanate ester composites with high permittivity and extremely low dielectric loss

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