Papers - HAYAKAWA, Naoki
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Improvement of AC Conditioning Effect in Vacuum by High Frequency Voltage Reviewed
R.Konagi, H.Kojima, S.Iitsuka, M.Kobayashi, N.Hayakawa
IEEJ Transactions on Electrical and Electronic Engineering Vol. 19 ( 11 ) page： 1781 - 1787 2024
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Enhancing Electrical Insulation Performance of Insulating Spacers using Functionally Graded Materials in Natural-Origin Gas GIS Reviewed
K.Okamoto, N.Hayakawa, K.Kato, N.Osawa, M.Kozako, H.Okubo
CIGRE Paris Session Vol. 11054 2024
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Effective High Frequency AC Conditioning in Vacuum Reviewed
R.Konagi, H.Kojima, S.Iitsuka, M.Kobayashi, N.Hayakawa
IEEE TRANSACTIONS ON DIELECTRICS AND ELECTRICAL INSULATION 2024
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Partial Discharge Progress and Breakdown Characteristics of Oil-impregnated Paper Insulation System for Capacitor Voltage Transformers Reviewed
Y.Nagaki, R.Hayashi, H.Kojima, M.Yoshida, N.Hayakawa
IEEE TRANSACTIONS ON DIELECTRICS AND ELECTRICAL INSULATION 2024
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コンデンサ形計器用変圧器の期待寿命評価方法および部分放電進展特性 Reviewed
永木雄也，林恭平，小島寛樹，吉田昌展，大谷彰，早川直樹
電気学会論文誌B 2023
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Breakdown Charge Dependence of Counter Electrode Material Adhesion and Dielectric Strength after Spark Conditioning in Vacuum Reviewed
N.Kita, H.Kojima, N.Hayakawa, H.Fukuda, K.Yamamura
IEEE TRANSACTIONS ON DIELECTRICS AND ELECTRICAL INSULATION 2023
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Volume Effect of Dynamic Breakdown Strength in Liquid Nitrogen under Transient Bubble Disturbance for Resistive Superconducting Fault Current Limiters Reviewed
N.Hayakawa, Y.Mori, H.Kojima
IEEE TRANSACTIONS ON DIELECTRICS AND ELECTRICAL INSULATION Vol. 29 ( 1 ) page： 264 - 269 2022
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Development of Sophisticated Cone-Type Insulating Spacer for 245 kV Class GIS by Functional Insulating Materials Reviewed
K.Okamoto, N.Hayakawa, M.Hikita, H.Okubo, K.Kato, N.Osawa
CIGRE Paris Session Vol. 10648 2022
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Electric Field Grading and Discharge Inception Voltage Improvement on HVDC GIS/GIL Spacer with Permittivity and Conductivity Graded Materials (ε/σ-FGM) Reviewed
Rachmawati, H.Kojima, K.Kato, N.Zebouchi, N.Hayakawa
IEEE TRANSACTIONS ON DIELECTRICS AND ELECTRICAL INSULATION Vol. 29 ( 5 ) page： 1811 - 1817 2022
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Melting and Generation of Micro-protrusions on Cathode Surface during Spark Conditioning Process in Vacuum Reviewed
N.Kita, F.Kondo, H.Kojima, N.Hayakawa, H.Fukuda, K.Yamamura
IEEE TRANSACTIONS ON DIELECTRICS AND ELECTRICAL INSULATION Vol. 29 ( 3 ) page： 1160 - 1166 2022
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Breakdown Characteristics of Cone-type ε-FGM Spacer for Gas Insulated Switchgears Reviewed
Y.Miyazaki, H.Kojima, H.Masui, H.Mitsudome, H.Yanase, K.Okamoto, K.Watanabe, K.Kato, N.Hayakawa
Vol. 141 ( 10 ) 2021.10
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Development of Insulation System to Prevent Local Carbonization inside Stator Core of a Product Inverter-fed Motor Reviewed
Vol. 141 ( 4 ) page： 260-268 2021.4
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DC Electric Field Distribution under Gas-Conductivity-Dominant Condition in Gas-Solid Composite Insulation Systems Reviewed
Vol. 141 ( 2 ) page： 156-163 2021.2
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Dielectric characteristics of liquid nitrogen / synthetic paper composite insulation system for extra high voltage HTS cable Reviewed
N.Hayakawa, K.Yamakami, T.Masuda, H.Kojima
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY Vol. 31 ( 5 ) 2021
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Time and Space Transition of DC Electric Field Distribution Based on Emerging Field by Accumulated Charge in Gas-solid Composite Insulation Structure Reviewed
R.Nakane, N.Hayakawa, H.Okubo
IEEE TRANSACTIONS ON DIELECTRICS AND ELECTRICAL INSULATION 2021
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Time Transition of Activated Conductivity Distribution in Air and Charge Accumulation in Air-solid Composite Insulation Systems under DC Partial Discharge Reviewed
R.Nakane, H.Kojima, N.Hayakawa
IEEE TRANSACTIONS ON DIELECTRICS AND ELECTRICAL INSULATION 2021
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Electric Field Simulation of Permittivity and Conductivity Graded Materials (e/s-FGM) for HVDC GIS Spacers Reviewed International coauthorship
Rachmawati, H.Kojima, N.Hayakawa, K.Kato, N.Zebouchi
IEEE TRANSACTIONS ON DIELECTRICS AND ELECTRICAL INSULATION 2021
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Alternative Test Method of Internal Arcing for Replacing SF6 by Air in SF6 Insulated Power Equipment Reviewed
M.Kotari, M.Iwata, H.Kojima, N.Hayakawa
Engineering Research Express Vol. 3 ( 035005 ) 2021
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Partial Discharge Inception Voltage under Inverter Surge Voltage Considering Interactive Effects of Environmental Factors Reviewed
Vol. 140 ( 7 ) page： 349-356 2020.7
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絶縁油-プレスボード複合絶縁構成における直流電界ストレスの時間・空間推移特性 Reviewed
中根龍一，加藤克巳， 早川直樹，大久保仁
電気学会論文誌A Vol. 140 ( 2 ) page： 56-63 2020.2