Faculty Profiles - KOJIMA Hiroki

Presentations -

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電界特異性を回避した絶縁スペーサにおける誘電率傾斜機能材料の電界緩和効果

加藤克巳，満留博，柳瀬博雅，岡本健次，小島寛樹，早川直樹

平成30年電気学会全国大会

導電率傾斜機能材料（σ-FGM）による沿面放電電圧向上効果

大石涼太，伊豆淳宏，小島寛樹，加藤克巳，早川直樹

平成30年電気学会全国大会

可変配合注型法によるポスト型誘電率傾斜機能材料の作製

落合健太，大石涼太，小島寛樹，満留博，柳瀬博雅，岡本健次，加藤克巳，早川直樹

平成30年電気学会全国大会

抵抗型超電導限流器を模擬したパンケーキコイルモデルの動的絶縁破壊特性

民部昌孝，山上浩輝，小島寛樹，磯嶋茂樹，桑田稔，早川直樹

平成30年電気学会全国大会

インバータサージ電圧下における巻線の部分放電開始電圧に及ぼす気圧および湿度の複合的影響

梶武文，浅井洋光，小島寛樹，早川直樹

平成30年電気学会全国大会

空気中チャネル加熱絶縁破壊における高導電率チャネルの軸方向進展

杉野一樹，浅野竜大，小島寛樹，米須大吾，小林金也，六戸敏昭，早川直樹

平成30年電気学会全国大会

インバータサージ電圧下における巻線の部分放電開始電圧に及ぼす温度および湿度の複合的影響

梶武文，浅井洋光，小島寛樹，早川直樹

電気学会放電/誘電・絶縁材料/高電圧合同研究会 2018.1.26 電気学会放電/誘電・絶縁材料/高電圧技術委員会

Electric Field Relaxation Effect of Functionally Graded Materials (FGM) with Conductive Multilayer Coating International conference

R. Oishi, H. Kojima, N. Hayakawa, K. Kato

2017 IEEE Conference on Electrical Insulation and Dielectric Phenomena 2017.10.23 IEEE DEIS

Event date： 2017.10

Language：English Presentation type：Oral presentation (general)

Venue：Fort Worth Country：United States

For the insulation design of gas insulated power apparatus, the electric field grading and control are indispensable. We have proposed the application of σ-FGM (Functionally Graded Materials with spatial distribution of conductivity σ) to solid insulators as a novel technique of the electric field grading and control. In this paper, we fabricated the conductive multilayer coating for σ-FGM and investigated the electric field relaxation effect of σ-FGM on a GIS spacer surface. The fabrication results revealed that we could obtain the conductive 3-layer coating by using the dip coating method. The calculation results revealed the technical feasibility of electric field relaxation by σ-FGM with the conductive multilayer coating.

DOI： 10.1109/CEIDP.2017.8257494

Scopus

Surface Flashover Mechanism and Its Application to Diagnosis in Vacuum Interrupter Invited International conference

H. Kojima

4th International Conference on Electric Power Equipment - Switching Technology 2017.10.24 State Key Laboratory of Electrical Insulation and Power Equipment, Xi’an Jiaotong University

Event date： 2017.10

Language：English Presentation type：Oral presentation (invited, special)

Venue：Xi'an Country：China

The application of vacuum interrupters and vacuum circuit breakers for higher voltage level is strongly expected. In electrical insulation in vacuum, surface flashover on solid insulator is one of the main problems for the higher voltage vacuum interrupters. In this paper, through the review of our recent researches, we discuss on the initiation and development mechanisms of flashover in the configuration with electric field distribution almost perpendicular to the dielectrics surface. Usually, the flashover was begun by exclusive electron emission at the cathode; however, the large charging on the dielectric surface before the flashover allowed the flashover initiated by secondary electron emission avalanche to occur. The development characteristics of surface flashover agreed with the electron-stimulated outgassing mechanism. The flashover development characteristics were applied to the discharge diagnosis in vacuum, and the effectiveness of our proposed discharge discrimination method was verified.

DOI： 10.1109/ICEPE-ST.2017.8188902

Scopus

空気中チャネル加熱絶縁破壊に至る投入エネルギー密度

杉野一樹，小島寛樹，大嶽敦，小林金也，六戸敏明，早川直樹

平成29年電気学会基礎・材料・共通部門大会