Faculty Profiles - KOJIMA Hiroki

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Study on Breakdown Mechanism in Non-uniform Gap in Air by Ultra-high Speed Measurement

T. IwataI, H. Kojima, N. Hayakawa, F. Endo, H. Okubo, N. Yanagita, T. Kato, T. Rokunohe

2009.11.20

Improvement of Accuracy for Insulation Diagnosis in GIS by Simultaneous Measurement of Partial Discharge Current Waveform and UHF Signal

M. Yoshida, M. Asai, F. Endo, N. Hayakawa, H. Kojima, H. Okubo

2009.11.20

Small Current Characteristics under Impulse Voltage Applications in Vacuum

K. Aoki, H. Yasukawa, H. Kojima, M. Homma, T. Shioiri, H. Okubo

2009.11.20

SF₆ガス中金属異物の部分放電パルスと放射UHF電磁波との相関

浅井基希，鈴木啓介，小島寛樹，早川直樹，遠藤奎将，吉田昌展，大久保仁

2009年度放電学会年次大会

真空中アルミナ絶縁物上帯電が沿面放電経路に与える影響

石田亜成，小島寛樹，土屋賢治，大久保仁

2009年度放電学会年次大会

空気中ストリーマ放電の進展特性および絶縁破壊メカニズムの検討

岩田健，小島寛樹，早川直樹，遠藤奎将，柳田憲史，加藤達朗，六戸敏昭，大久保仁

2009年度放電学会年次大会

Partial Discharge Detection at Delamination of Electrode/Epoxy Interface in GIS Spacers International conference

D.A. Mansour, H. Kojima, N. Hayakawa, F. Endo, H. Okubo

2009 IEEE Conference on Electrical Insulation and Dielectric Phenomena 2009.10 IEEE Dielectrics and Electrical Insulation Society

Event date： 2009.10

Language：English Presentation type：Oral presentation (general)

Venue：Virginia Beach Country：United States

Partial Discharge (PD) measurements are very promising for insulation condition monitoring in Gas Insulated Switchgears (GISs). However, for accurate PD detection and diagnosis, there is a need for better understanding of physical mechanisms behind PD activity. Accordingly, we have been investigating the PD characteristics and associated mechanisms for electrode/epoxy delamination of GIS spacers as one of the most serious defects in GIS. The gas pressure inside delamination usually changes from sub-atmospheric pressure, just after delamination initiates, to filled SF6 gas pressure in the GIS tank, after SF6 gas permeates into the delamination area. Therefore, in this paper, the PD activity at different gas pressures, from 0.02 MPa to 0.4 MPa, is acquired. The relative PD generation rate and its phase appearance are analyzed at different pressures and then discussed from the viewpoint of PD mechanism and PD detection. Experimental results show that, with increasing pressure, the peak of the PD generation rate shifts from around zero crossing like void-type discharge to around a peak of ac voltage, before PD pulses vanish at high pressure for the applied electric field stress. The obtained results could be useful for delamination diagnosis in GIS spacers. © 2009 IEEE.

DOI： 10.1109/CEIDP.2009.5377864

Scopus

Other Link： https://www.webofscience.com/wos/woscc/full-record/WOS:000279096900050

UHF Technique and Current Pulse Waveform Analysis for Partial Discharge Measurement International conference

H. Okubo, F. Endo, N. Hayakawa, H. Kojima, M. Yoshida, K. Uchida

CIGRE SC D1 Colloquium

Development of 2 MVA Class Superconducting Fault Current Limiting Transformer (SFCLT) with YBCO Coated Conductors International coauthorship International conference

M. Kotari, K. Omura, H. Kojima, N. Hayakawa, F. Endo, M. Noe, H. Okubo

9th European Conference on Applied Superconductivity

Partial Discharge Activities under AC/Impulse Superimposed Voltage in LN₂/Polypropylene Laminated Paper Insulation System for HTS Cables International conference

N. Hayakawa, R. Yamaguchi, Y. Ukai, H. Kojima, F. Endo, H. Okubo

9th European Conference on Applied Superconductivity

真空バルブ中間シールドの電界最適化自動計算における収束性の検討

鈴木啓也，加藤克巳，小島寛樹，大久保仁

平成21年度電気関係学会東海支部連合大会

真空中インパルス電圧印加時における微小電流の発生特性

青木圭太，安川英明，小島寛樹，本間三孝，塩入哲，大久保仁

平成21年電気学会基礎・材料・共通部門大会

Gas Pressure Dependency of Partial Discharge Activity at Electrode/Epoxy Delamination in GIS Spacer

D.A. Mansour, H. Kojima, N. Hayakawa, F. Endo, H. Okubo

真空中固体絶縁物上正極性帯電がインパルス沿面放電の進展に与える影響

石田亜成，加藤秀紀，小島寛樹，土屋賢治，大久保仁

平成21年度電気関係学会東海支部連合大会

真空中Cu-Cr電極のインパルスコンディショニング過程の定量的検討

安川英明，青木圭太，小島寛樹，大久保仁，佐藤裕昌，斉藤仁，野田泰司

平成21年度電気関係学会東海支部連合大会

SF₆ガス中金属異物の部分放電特性に及ぼす電極間微小ギャップの影響

浅井基希，小島寛樹，早川直樹，遠藤奎将，吉田昌展，大久保仁

平成21年度電気関係学会東海支部連合大会

2MVA級高温超電導限流変圧器（SFCLT）YBCOコイルの限流動作特性

神足将司，小島寛樹，早川直樹，遠藤奎将，大久保仁

平成21年度電気関係学会東海支部連合大会

電力システムの最適保守に及ぼす需要規模の影響

鈴木陽太郎，小島寛樹，早川直樹，遠藤奎将，大久保仁

平成21年度電気関係学会東海支部連合大会

空気中における2次ストリーマの進展と破壊特性

岩田健，吉田聡，小島寛樹，早川直樹，遠藤奎将，加藤達朗，六戸敏昭，大久保仁

平成21年電気学会基礎・材料・共通部門大会

Leader Discharge Development and Breakdown Criteria under Non-uniform Electric Field in SF₆ International conference

H. Kojima, S. Yoshida, T. Iwata, N. Hayakawa, F. Endo, H. Okubo

16th International Symposium on High Voltage Engineering

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