論文 - 早川 直樹
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Improvement of AC Conditioning Effect in Vacuum by High Frequency Voltage 査読有り
R.Konagi, H.Kojima, S.Iitsuka, M.Kobayashi, N.Hayakawa
IEEJ Transactions on Electrical and Electronic Engineering 19 巻 ( 11 ) 頁： 1781 - 1787 2024年
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Enhancing Electrical Insulation Performance of Insulating Spacers using Functionally Graded Materials in Natural-Origin Gas GIS 査読有り
K.Okamoto, N.Hayakawa, K.Kato, N.Osawa, M.Kozako, H.Okubo
CIGRE Paris Session 11054 巻 2024年
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Partial Discharge Progress and Breakdown Characteristics of Oil-impregnated Paper Insulation System for Capacitor Voltage Transformers 査読有り
Y.Nagaki, R.Hayashi, H.Kojima, M.Yoshida, N.Hayakawa
IEEE TRANSACTIONS ON DIELECTRICS AND ELECTRICAL INSULATION 2024年
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Effective High Frequency AC Conditioning in Vacuum 査読有り
R.Konagi, H.Kojima, S.Iitsuka, M.Kobayashi, N.Hayakawa
IEEE TRANSACTIONS ON DIELECTRICS AND ELECTRICAL INSULATION 2024年
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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 査読有り
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年
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Breakdown Charge Dependence of Counter Electrode Material Adhesion and Dielectric Strength after Spark Conditioning in Vacuum 査読有り
N.Kita, H.Kojima, N.Hayakawa, H.Fukuda, K.Yamamura
IEEE TRANSACTIONS ON DIELECTRICS AND ELECTRICAL INSULATION 2023年
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Volume Effect of Dynamic Breakdown Strength in Liquid Nitrogen under Transient Bubble Disturbance for Resistive Superconducting Fault Current Limiters 査読有り
N.Hayakawa, Y.Mori, H.Kojima
IEEE TRANSACTIONS ON DIELECTRICS AND ELECTRICAL INSULATION 29 巻 ( 1 ) 頁： 264 - 269 2022年
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Development of Sophisticated Cone-Type Insulating Spacer for 245 kV Class GIS by Functional Insulating Materials 査読有り
K.Okamoto, N.Hayakawa, M.Hikita, H.Okubo, K.Kato, N.Osawa
CIGRE Paris Session 10648 巻 2022年
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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) 査読有り
Rachmawati, H.Kojima, K.Kato, N.Zebouchi, N.Hayakawa
IEEE TRANSACTIONS ON DIELECTRICS AND ELECTRICAL INSULATION 29 巻 ( 5 ) 頁： 1811 - 1817 2022年
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Melting and Generation of Micro-protrusions on Cathode Surface during Spark Conditioning Process in Vacuum 査読有り
N.Kita, F.Kondo, H.Kojima, N.Hayakawa, H.Fukuda, K.Yamamura
IEEE TRANSACTIONS ON DIELECTRICS AND ELECTRICAL INSULATION 29 巻 ( 3 ) 頁： 1160 - 1166 2022年
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Breakdown Characteristics of Cone-type ε-FGM Spacer for Gas Insulated Switchgears 査読有り
Y.Miyazaki, H.Kojima, H.Masui, H.Mitsudome, H.Yanase, K.Okamoto, K.Watanabe, K.Kato, N.Hayakawa
141 巻 ( 10 ) 2021年10月
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Development of Insulation System to Prevent Local Carbonization inside Stator Core of a Product Inverter-fed Motor 査読有り
141 巻 ( 4 ) 頁： 260-268 2021年4月
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DC Electric Field Distribution under Gas-Conductivity-Dominant Condition in Gas-Solid Composite Insulation Systems 査読有り
141 巻 ( 2 ) 頁： 156-163 2021年2月
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Dielectric characteristics of liquid nitrogen / synthetic paper composite insulation system for extra high voltage HTS cable 査読有り
N.Hayakawa, K.Yamakami, T.Masuda, H.Kojima
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY 31 巻 ( 5 ) 2021年
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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 査読有り
R.Nakane, N.Hayakawa, H.Okubo
IEEE TRANSACTIONS ON DIELECTRICS AND ELECTRICAL INSULATION 2021年
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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 査読有り
R.Nakane, H.Kojima, N.Hayakawa
IEEE TRANSACTIONS ON DIELECTRICS AND ELECTRICAL INSULATION 2021年
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Electric Field Simulation of Permittivity and Conductivity Graded Materials (e/s-FGM) for HVDC GIS Spacers 査読有り 国際共著
Rachmawati, H.Kojima, N.Hayakawa, K.Kato, N.Zebouchi
IEEE TRANSACTIONS ON DIELECTRICS AND ELECTRICAL INSULATION 2021年
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Alternative Test Method of Internal Arcing for Replacing SF6 by Air in SF6 Insulated Power Equipment 査読有り
M.Kotari, M.Iwata, H.Kojima, N.Hayakawa
Engineering Research Express 3 巻 ( 035005 ) 2021年
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Partial Discharge Inception Voltage under Inverter Surge Voltage Considering Interactive Effects of Environmental Factors 査読有り
140 巻 ( 7 ) 頁： 349-356 2020年7月
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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 査読有り
中根龍一，加藤克巳， 早川直樹，大久保仁
電気学会論文誌A 140 巻 ( 2 ) 頁： 56-63 2020年2月
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インバータ駆動機におけるカーボン遊離現象の基礎検討 査読有り
吉武勇一郎，小島啓明， 笠井友樹，丸山正一， 小島寛樹，早川直樹
電気学会論文誌A 140 巻 ( 1 ) 頁： 40-47 2020年1月
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Quench-induced Dynamic Breakdown Characteristics of HTS Pancake Coil Model in Liquid Nitrogen for Resistive SFCL 招待有り 査読有り
N.Hayakawa, M.Mimbu, Y.Mori, H.Kojima, S.Isojima, M.Kuwata
Journal of Physics: Conference Series (JPCS) 1559 巻 頁： 12100 2020年
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Fault Current Limitation Coordination of Multiple SFCLs in IEEE 14-Bus Test System 査読有り
N.Hayakawa, Y.Mori, H.Kojima
Journal of Physics: Conference Series (JPCS) 1559 巻 頁： 12138 2020年
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Resin injection behavior in process of manufacturing insulation spacer with permittivity gradient using computational fluid dynamics
Imai Takahiro, Hoshina Yoshikazu, Kojima Hiroki, Hayakawa Naoki
IEEE TRANSACTIONS ON DIELECTRICS AND ELECTRICAL INSULATION 26 巻 ( 5 ) 頁： 1669-1677 2019年10月
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Comparison of permittivity gradient in resin injected and simulated cone-shaped spacers
Imai Takahiro, Takeuchi Miwa, Hoshina Yoshikazu, Kojima Hiroki, Hayakawa Naoki
IEEE TRANSACTIONS ON DIELECTRICS AND ELECTRICAL INSULATION 26 巻 ( 5 ) 頁： 1678-1685 2019年10月
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Dynamic Breakdown Characteristics of a Pancake Coil Model for Resistive-Type Superconducting Fault Current Limiters
Hayakawa Naoki, Mimbu Masataka, Kojimao Hiroki, Isojima Shigeki, Kuwata Minoru
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY 29 巻 ( 5 ) 2019年8月
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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 査読有り
梶武文，浅井洋光，小島寛樹，早川直樹
電気学会論文誌A 139 巻 ( 1 ) 頁： 30-37 2019年1月
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Simulation on Discharge Inception Voltage Improvement of GIS Spacer with Permittivity Graded Materials (epsilon-FGM) Using Flexible Mixture Casting Method
Hayakawa Naoki, Miyaji Yoshitaka, Kojima Hiroki, Kato Katsumi
IEEE TRANSACTIONS ON DIELECTRICS AND ELECTRICAL INSULATION 25 巻 ( 4 ) 頁： 1318-1323 2018年8月
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Volume Effect of Dynamic Breakdown Strength in LN2 for Insulation Design of Resistive Superconducting Fault Current Limiters
Hayakawa Naoki, Ishida Kazuki, Mimbu Masataka, Kojima Hiroki, Isojima Shigeki, Kuwata Minoru
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY 28 巻 ( 4 ) 2018年6月
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Fault Current Limitation Coordination in Electric Power Grid With Superconducting Fault Current Limiters
Hayakawa Naoki, Maeno Yuya, Kojima Hiroki
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY 28 巻 ( 4 ) 2018年6月
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誘電率傾斜機能材料(ε-FGM)を用いたGISスペーサモデルの作製とSF6ガス中絶縁破壊電圧の理論的推定 査読有り
宮路仁崇，小島寛樹， 加藤克巳，早川直樹
電気学会論文誌A 138 巻 ( 4 ) 頁： 155-162 2018年
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Discharge Pattern Discrimination in Vacuum Interrupter with Non-contact Measurement of Shield Potential
Kong Fei, Kojima Hiroki, Hayakawa Naoki, Kimura Toshinori, Tsukima Mitsuru
IEEE TRANSACTIONS ON DIELECTRICS AND ELECTRICAL INSULATION 24 巻 ( 5 ) 頁： 3265-3269 2017年10月
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Optimum Breakdown Charge for Maximum Dielectric Strength in Spark Conditioning in Vacuum under a Non-uniform Electric Field
Kojima H., Takahashi T., Hayakawa N., Hasegawa K., Sakaki M.
IEEE TRANSACTIONS ON DIELECTRICS AND ELECTRICAL INSULATION 24 巻 ( 4 ) 頁： 2660-2665 2017年8月
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Electrical Insulation Characteristics and Mechanisms of Low Dielectric Loss Materials for High-Voltage HTS Cables
Hayakawa Naoki, Ishida Kazuki, Matsuoka Tatsuya, Kojima Hiroki
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY 27 巻 ( 4 ) 2017年6月
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Breakdown Characteristics and Mechanisms of Liquid Nitrogen Under Transient Thermal Stress for Superconducting Fault Current Limiters
Hayakawa Naoki, Matsuoka Tatsuya, Kojima Hiroki, Isojima Shigeki, Kuwata Minoru
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY 27 巻 ( 4 ) 2017年6月
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Calculation Model for Predicting Partial-discharge Inception Voltage in a Non-uniform Air Gap while Considering the Effect of Humidity
Rokunohe Toshiaki, Kato Tatsuro, Kojima Hiroki, Hayakawa Naoki, Okubo Hitoshi
IEEE TRANSACTIONS ON DIELECTRICS AND ELECTRICAL INSULATION 24 巻 ( 2 ) 頁： 1123-1130 2017年4月
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ナノ粒子添加絶縁油の交流電気絶縁破壊電圧の向上メカニズム 査読有り
小島寛樹，近藤貴文，花井正広，早川直樹
電気学会論文誌A 137 巻 ( 2 ) 頁： 101-106 2017年
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Discharge Characteristics of Composite Insulation System with Floating Electrode and Solid Insulator in Vacuum 査読有り
F.Kong, Y.Nakano, H.Kojima, N.Hayakawa, T.Kimura, M.Tsukima
IEEE Trans. on Dielectrics and Electrical Insulation 23 巻 ( 2 ) 頁： 1219-1225 2016年
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Discharge Characteristics for Various Discharge Patterns under Negative Lightning Impulse Voltage in Vacuum 査読有り
F.Kong, Y.Nakano, H.Kojima, N.Hayakawa, T.Kimura, M.Tsukima
IEEE Trans. on Dielectrics and Electrical Insulation 23 巻 ( 2 ) 頁： 813-818 2016年
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Fabrication and Simulation of Permittivity Graded Materials for Electric Field Grading of Gas Insulated Power Apparatus 査読有り
N.Hayakawa, J.Ishiguro, H.Kojima, K.Kato, H.Okubo
IEEE Trans. on Dielectrics and Electrical Insulation 23 巻 ( 1 ) 頁： 547-554 2016年
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Classification of Impulse Breakdown Mechanisms under Non-uniform Electric Field in Air 査読有り
H.Kojima, K.Hotta, T.Kitamura, N.Hayakawa, A.Otake, K.Kobayashi, T.Kato, T.Rokunohe H.Okubo
IEEE Trans. on Dielectrics and Electrical Insulation 23 巻 ( 1 ) 頁： 194-201 2016年
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Analysis of Conditioning and Damaging Process in Vacuum Based on Breakdown Probability Distribution 査読有り
H.Kojima, Y.Otake, T.Takahashi, N.Hayakawa, K.Hasegawa, H.Saito, M.Sakaki
IEEE Trans. on Dielectrics and Electrical Insulation 23 巻 ( 1 ) 頁： 43-48 2016年
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Control and Suppression of Impulse Surface Flashover in Vacuum Based on Discharge Development Mechanisms 査読有り
Y.Nakano, H.Kojima, K.Tsuchiya, N.Hayakawa
IEEE Trans. on Dielectrics and Electrical Insulation 23 巻 ( 1 ) 頁： 35-42 2016年
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Pressure Dependence and Size Effect of LN2 Breakdown Characteristics under Transient Thermal Stress 査読有り
N.Hayakawa, T.Matsuoka, K.Ishida, H.Kojima, S.Isojima, M.Kuwata
IEEE Trans. on Applied Superconductivity 26 巻 ( 3 ) 頁： 7700604 2016年
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平角線モータにおける部分放電開始電圧のばらつき低減方法 査読有り
脇本亨，小島寛樹，早川直樹
電気学会論文誌A 136 巻 ( 3 ) 頁： 121-127 2016年
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真空中沿面フラッシオーバ進展過程における絶縁物上過渡帯電存在時の実効的２次電子放出係数 査読有り
中野裕介，小島寛樹，土屋賢治，早川直樹
電気学会論文誌A 136 巻 ( 3 ) 頁： 128-134 2016年
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Dependence of Spark Conditioning on Breakdown Charge and Electrode Material under a Non-Uniform Electric Field 査読有り
H.Kojima, T.Takahashi, N.Hayakawa, K.Hasegawa, H.Saito, M.Sakaki
IEEE Trans. on Dielectrics and Electrical Insulation 23 巻 ( 5 ) 頁： 3224-3230 2016年
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真空中の複合絶縁系における放電パターンの識別 査読有り
孔飛，小島寛樹，木村俊則，月間満，早川直樹
電気学会論文誌A 136 巻 ( 9 ) 頁： 594-602 2016年
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Measurement and Evaluation of Partial Discharge Inception Voltage for Enameled Rectangular Wires under AC Voltage 査読有り
T.Wakimoto, H.Kojima, N.Hayakawa
IEEE Trans. on Dielectrics and Electrical Insulation 23 巻 ( 6 ) 頁： 3566-3574 2016年
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Power Flow Control and Maintenance Strategy of Transformers in Transmission and Distribution Systems 査読有り
H.Kojima, K.Fukaya, N.Hayakawa, M.Hanai, H.Okubo
135 巻 ( 5 ) 頁： 316-321 2015年
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Experimental Results of 275 kV-3 kA REBCO HTS Power Cable 査読有り
M.Yagi, J.Liu, S.Mukoyama, T.Mitsuhashi, J.Teng, N.Hayakawa, X.Wang, A.Ishiyama,
IEEE Trans. on Applied Superconductivity 25 巻 ( 3 ) 頁： 5401405 2015年
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Fault Current Limitation Coordination in Power Transmission System with Superconducting Fault Current Limiting Cables (SFCLC) 査読有り
H.Kojima, T.Osawa, N.Hayakawa
IEEE Trans. on Applied Superconductivity 25 巻 ( 3 ) 頁： 5401904 2015年
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Quench-Induced Dynamic Breakdown Characteristics of LN2 and LN2/PPLP Composite Electrical Insulation System for Superconducting Power Apparatus 査読有り
N.Hayakawa, T.Matsuoka, S.Nishimachi, H.Kojima
IEEE Trans. on Applied Superconductivity 25 巻 ( 3 ) 頁： 7700304 2015年
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Impulse Surface Flashover Development Associated with Transient Charging by Explosive Electron Emission in Vacuum 査読有り
Y.Nakano, H.Kojima, K.Tsuchiya, N.Hayakawa
IEEE Trans. on Dielectrics and Electrical Insulation 22 巻 ( 4 ) 頁： 2390-2397 2015年
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Size Effect on Breakdown Strength in Sub-cooled Liquid Nitrogen for Superconducting Power Apparatus 査読有り
N.Hayakawa, S.Nishimachi, H.Kojima, H.Okubo
IEEE Trans. on Dielectrics and Electrical Insulation 22 巻 ( 5 ) 頁： 2565-2571 2015年
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真空中における突発的電子放出に起因する沿面フラッシオーバ進展過程の過渡帯電特性 査読有り
中野裕介，小島寛樹，土屋賢治，早川直樹
電気学会論文誌A 134 巻 ( 11 ) 頁： 578-584 2014年
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Influence of longitudinal temperature distribution on current limiting function of Superconducting Fault Current Limiting Cable (SFCLC) 査読有り
H.Kojima, T.Osawa, N.Hayakawa , M.Hanai, H.Okubo
Journal of Physics: Conference Series (JPCS) 507 巻 頁： 032026 2014年
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A Novel Electrical Insulating Material for 275 kV High-Voltage HTS Cable with Low Dielectric Loss 査読有り
N.Hayakawa, S.Nishimachi, O.Maruyama, T.Ohkuma, J.Liu, M.Yagi
Journal of Physics: Conference Series (JPCS) 507 巻 頁： 032021 2014年
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Pre-discharge and Flashover Characteristics of Impulse Surface Discharge in Vacuum 査読有り
Y.Nakano, H.Kojima, N.Hayakawa, K.Tsuchiya, H.Okubo
IEEE Trans. on Dielectrics and Electrical Insulation 21 巻 ( 1 ) 頁： 403-410 2014年
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Technique for Discriminating the Type of PD in SF6 Gas Using the UHF Method and the PD Current with a Metallic Particle 査読有り
M.Hanai, H.Kojima, N.Hayakawa, R.Mizuno, H.Okubo
IEEE Trans. on Dielectrics and Electrical Insulation 21 巻 ( 1 ) 頁： 88-95 2014年
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Physical Mechanisms of Partial Discharges at Nitrogen Filled Delamination in Epoxy Cast Resin Power Apparatus 査読有り
D.-E.A.Mansour, H.Kojima, N.Hayakawa, M.Hanai, H.Okubo
IEEE Trans. on Dielectrics and Electrical Insulation 20 巻 ( 2 ) 頁： 454-461 2013年
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Status of 275 kV Class REBCO Superconducting Cable Development 査読有り
S.Mukoyama, M.Yagi, T.Mitsuhashi, T.Nomura, J.Ten, R.Nakayama, T.Ohkuma, O.Maruyama, Y.Aoki, T.Saitoh, N.Amemiya, A.Ishiyama, N.Hayakawa
IEEE Trans. on Applied Superconductivity 23 巻 ( 3 ) 頁： 5402804 2013年
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Feasibility Study on Superconducting Power Flow Controller and Fault Current Limiter (SPFCL) 査読有り
N.Hayakawa, X.Mao, H.Kojima, M.Hanai, H.Okubo, N.Kashima, S.Nagaya, S.Sugimoto
IEEE Trans. on Applied Superconductivity 23 巻 ( 3 ) 頁： 5600504 2013年
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Development of 66 kV and 275 kV Class REBCO HTS Power Cables 査読有り
O.Maruyama, T.Ohkuma, T.Masuda, Y.Ashibe, S.Mukoyama, M.Yagi, T.Saitoh, T.Hasegawa, N.Amemiya, A.Ishiyama, N.Hayakawa
IEEE Trans. on Applied Superconductivity 23 巻 ( 3 ) 頁： 5401405 2013年
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部分放電メカニズムに基づくGIS中金属異物形状同定手法 査読有り
小島寛樹，鈴木隆文，早川直樹，花井正広，大久保仁
電気学会論文誌B 133 巻 ( 1 ) 頁： 114-120 2013年
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Integration of Asset Management and Smart Grid with Intelligent Grid Management System 査読有り
M.Hanai, H.Kojima, N.Hayakawa, K.Shinoda, H.Okubo
IEEE Trans. on Dielectrics and Electrical Insulation 20 巻 ( 6 ) 頁： 2195-2202 2013年
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Charge behavior in Palm Fatty Acid Ester Oil (PFAE) / pressboard composite insulation system under voltage application 査読有り
H.Kojima. N.Hayakawa, H.Okubo, K.Kato, K.Kawanishi, H.Koide
IEEE Trans. on Dielectrics and Electrical Insulation 19 巻 ( 2 ) 頁： 419-423 2012年
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Estimation of Partial Discharge Inception Voltage of Magnet Wire under Inverter Surge Voltage by Volume-Time Theory 査読有り
N.Hayakawa, F.Shimizu, H.Okubo
IEEE Trans. on Dielectrics and Electrical Insulation 19 巻 ( 2 ) 頁： 550-557 2012年
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Feasibility Study on High Temperature Superconducting Fault Current Limiting Cable (SFCLC) Using Flux Flow Resistance 査読有り
H.Kojima, F.Kato, M.Hanai, N.Hayakawa, H.Okubo
IEEE Trans. on Applied Superconductivity 22 巻 ( 2 ) 頁： 4800105 2012年
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Current limitation and recovery function for superconducting fault current limiting transformer (SFCLT) 査読有り
J.Himbele, H.Kojima, N.Hayakawa, M.Hanai, H.Okubo
Physics Procedeia 36 巻 頁： 841-844 2012年
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Superconducting Fault Current Limiting Cable (SFCLC) with Current Limiting and Recovery Function 査読有り
H.Kojima, F.Kato, N.Hayakawa, M.Hanai, H.Okubo
Physics Procedeia 36 巻 頁： 1296-1300 2012年
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Recent Progress in Electrical Insulation Techniques for HTS Power Apparatus 査読有り
N.Hayakawa, H.Kojima, M.Hanai, H.Okubo
Physics Procedeia 36 巻 頁： 1305-1308 2012年
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周波数応答解析によるモータサージ電圧の推定と抑制 査読有り
脇本亨，高橋芳光，木村統公，鳴海礼斗史，早川直樹
電気学会論文誌A 132 巻 ( 8 ) 頁： 630-637 2012年
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Model Cable Tests for a 275 kV 3 kA HTS Power Cable 査読有り
S.Mukoyama, M.Yagi, T.Yonemura, T.Nomura, N.Fujiwara, Y.Ichikawa, Y.Aoki, T.Saitoh, N.Amemiya, A.Ishiyama, N.Hayakawa
IEEE Trans. on Applied Superconductivity 21 巻 ( 3 ) 頁： 976-979 2011年
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Analysis of Current Limiting and Recovery Characteristics of Superconducting Fault Current Limiting Transformer (SFCLT) with YBCO Coated Conductors 査読有り
N.Hayakawa, T.Kito, H.Kojima, M.Hanai, H.Okubo
IEEE Trans. on Applied Superconductivity 21 巻 ( 3 ) 頁： 1422-1425 2011年
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Current Limiting and Recovery Characteristics of 2 MVA Class Superconducting Fault Current Limiting Transformer (SFCLT) 査読有り
H.Kojima, M.Kotari, T.Kito, N.Hayakawa, M.Hanai, H.Okubo
IEEE Trans. on Applied Superconductivity 21 巻 ( 3 ) 頁： 1401-1404 2011年
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Development Process of Impulse Surface Flashover on Alumina Dielectrics in Vacuum 査読有り
H.Kojima, N.Hayakawa, T.Ishida, H.Okubo, K.Tsuchiya
IEEE Trans. on Dielectrics and Electrical Insulation 18 巻 ( 3 ) 頁： 918-923 2011年
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Evaluation of UHF Method for Partial Discharge Measurement by Simultaneous Observation of UHF Signal and Current Pulse Waveforms 査読有り
M.Yoshida, H.Kojima, N.Hayakawa, F.Endo, H.Okubo
IEEE Trans. on Dielectrics and Electrical Insulation 18 巻 ( 2 ) 頁： 425-431 2011年
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Progress in Development of Superconducting Fault Current Limiting Transformer (SFCLT) 査読有り
N.Hayakawa, H.Kojima, M.Hanai, H.Okubo
IEEE Trans. on Applied Superconductivity 21 巻 ( 3 ) 頁： 1397-1400 2011年
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湿度の影響を考慮した気中不平等ギャップにおける部分放電開始計算モデルの開発 査読有り
柳田憲史，加藤達朗，六戸敏昭，岩田健，小島寛樹，早川直樹，大久保仁
電気学会論文誌A 131 巻 ( 12 ) 頁： 1017-1023 2011年
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Conditioning Mechanism of Cu-Cr Electrode Based on Electrode Surface State under Impulse Voltage Application in Vacuum 査読有り
H.Kojima, N.Hayakawa, R.Nishimura, H.Okubo, H.Sato, H.Saito, Y.Noda
IEEE Trans. on Dielectrics and Electrical Insulation 18 巻 ( 6 ) 頁： 2108-2114 2011年
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部分放電の時系列測定によるGIS内部の欠陥状態識別 査読有り
吉田昌展，鈴木啓介，小島寛樹，早川直樹，花井正広，大久保仁
電気学会論文誌B 131 巻 ( 11 ) 頁： 905-911 2011年
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Partial Discharge Activities under AC/Impulse Superimposed Voltage in LN2/Polypropylene Laminated Paper Insulation System for HTS Cables 査読有り
N.Hayakawa, R.Yamaguchi, U.Ukai, H.Kojima, F.Endo, H.Okubo
Journal of Physics: Conference Series (JPCS) 234 巻 ( 032020 ) 2010年
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Permittivity Characteristics of Epoxy/Alumina Nanocomposite with High Particle Dispersibility by Combining Ultrasonic Wave and Centrifugal Force 査読有り
M.Kurimoto, H.Okubo, K.Kato, M.Hanai, Y.Hoshina, M.Takei, N.Hayakawa
IEEE Trans. on Dielectrics and Electrical Insulation 17 巻 ( 4 ) 頁： 1268-1275 2010年
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Charge Accumulation Effects on Time Transition of Partial Discharge Activity at GIS Spacer Defects 査読有り
D.A.Mansour, K.Nishizawa, H.Kojima, N.Hayakawa, F.Endo, H.Okubo
IEEE Trans. on Dielectrics and Electrical Insulation 17 巻 ( 1 ) 頁： 247-255 2010年
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Dielectric Properties of Epoxy/Alumina Nanocomposite Influenced by Agglomerates Control 査読有り
M.Kurimoto, H.Okubo, K.Kato, M.Hanai, Y.Hoshina, M.Takei, N.Hayakawa
IEEE Trans. on Dielectrics and Electrical Insulation 17 巻 ( 3 ) 頁： 1268-1275 2010年
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Partial Discharge and Associated Mechanisms for Micro Gap Delamination at Epoxy Spacer in GIS 査読有り
D.A.Mansour, K.Nishizawa, H.Kojima, N.Hayakawa, F.Endo, H.Okubo
IEEE Trans. on Dielectrics and Electrical Insulation 17 巻 ( 3 ) 頁： 861-867 2010年
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Development of 2 MVA Class Superconducting Fault Current Limiting Transformer (SFCLT) with YBCO Coated Conductors 査読有り
M.Kotari, H.Kojima, N.Hayakawa, F.Endo, H.Okubo
Journal of Physics: Conference Series (JPCS) 234 巻 ( 032070 ) 頁： - 2010年
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Surface Charge Accumulation and Partial Discharge Activity for Small Gaps of Electrode/Epoxy Interface in SF6 Gas 査読有り
D.A.Mansour, H.Kojima, N.Hayakawa, F.Endo, H.Okubo
IEEE Trans. on Dielectrics and Electrical Insulation 16 巻 ( 4 ) 頁： 1150-1157 2009年
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Dynamic Thermal Characteristics of HTS Coil for Conduction-cooled SMES 査読有り
H.Kojima, X.Chen, N.Hayakawa, F.Endo, H.Okubo
IEEE Trans. on Applied Superconductivity 19 巻 ( 3 ) 頁： 2036-2039 2009年
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Current Limiting Characteristics of Parallel-Connected YBCO Coated Conductors for High-Tc Superconducting Fault Current Limiting Transformer (HTc-SFCLT) 査読有り
K.Omura, H.Kojima, N.Hayakawa, F.Endo, M.Noe, H.Okubo
IEEE Trans. on Applied Superconductivity 19 巻 ( 3 ) 頁： 1880-1883 2009年
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*Time Variation of Partial Discharge Activity Leading to Breakdown of Magnet Wire under Repetitive Surge Voltage Application 査読有り
N.Hayakawa, H.Inano, Y.Nakamura, H.Okubo
IEEE Trans. on Dielectrics and Electrical Insulation 15 巻 ( 6 ) 頁： 1701-1706 2008年
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*Partial Discharge Activity in Electrical Insulation for High Temperature Superconducting (HTS) Cables 査読有り
H.Okubo, H.Kojima, F.Endo, K.Sahara, R.Yamaguchi, N.Hayakawa
IEEE Trans. on Dielectrics and Electrical Insulation 15 巻 ( 3 ) 頁： 647-654 2008年
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*Self-recovery Characteristics of High-Tc Superconducting Fault Current Limiting Transformer (HTc-SFCLT) with 2G Coated Conductors 査読有り
H.Kojima, S.Ito, N.Hayakawa, F.Endo, M.Noe, H.Okubo
Journal of Physics: Conference Series 頁： 12154 2008年
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*Quench-induced Partial Discharge Characteristics of HTS Cables 査読有り
N.Hayakawa, S.Ueyama, H.Kojima, F.Endo, Y.Ashibe, T.Masuda, M.Hirose
Journal of Physics: Conference Series 頁： 12053 2008年
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Electrical Insulation Characteristics of HTS Cables under Quench-induced Thermal Stress Condition 査読有り
N.Hayakawa, S.Ueyama, H.Kojima, F.Endo, T.Masuda, M.Hirose
IEEE Trans. on Applied Superconductivity 17 巻 ( 2 ) 頁： 1660-1663 2007年
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*Breakdown Characteristics of N2O Gas Mixtures for Quasiuniform Electric Field under Lightning Impulse Voltage 査読有り
H.Kojima, O.Kinoshita, N.Hayakawa, F.Endo, H.Okubo, M.Yoshida, T.Ogawa
IEEE Trans. on Dielectrics and Electrical Insulation 14 巻 ( 6 ) 頁： 1492-1497 2007年
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Technical Development on Partial Discharge Measurement and Electrical Insulation Techniques for Low Voltage Motors Driven by Voltage Inverters 査読有り
H.Okubo, N.Hayakawa, G.C.Montanari
IEEE Trans. on Dielectrics and Electrical Insulation 14 巻 ( 6 ) 頁： 1516-1530 2007年
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Partial Discharge Inception and Propagation Characteristics of Magnet Wire for Inverter-Fed Motor under Surge Voltage Condition 査読有り
N.Hayakawa, M.Morikawa, H.Okubo
IEEE Trans. on Dielectrics and Electrical Insulation 14 巻 ( 1 ) 頁： 39-45 2007年
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Thermal Runaway Characteristics of Bi2212 Coil for Conduction-cooled SMES 査読有り
H.Kojima, N.Hayakawa, S.Noguchi, F.Endo, N.Hirano, S.Nagaya, H.Okubo
IEEE Trans. on Applied Superconductivity 17 巻 ( 2 ) 頁： 1959-1962 2007年
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High-Tc Superconducting Fault Current Limiting Transformer (HTc-SFCLT) with 2G Coated Conductors 査読有り
H.Okubo, C.Kurupakorn, S.Ito, H.Kojima, N.Hayakawa, F.Endo, M.Noe
IEEE Trans. on Applied Superconductivity 17 巻 ( 2 ) 頁： 1768-1771 2007年
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Electrical and Thermal Characteristics of Bi2212/Ag HTS Coils for Conduction-cooled SMES 査読有り
N.Hayakawa, S.Noguchi, C.Kurupakorn, H.Kojima, F.Endo, N.Hirano, S.Nagaya, H.Okubo
Journal of Physics: Conference Series 43 巻 頁： 813-816 2006年
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N2O混合ガスの絶縁特性におけるシナジズム効果 査読有り
早川直樹，木下修，小島寛樹，遠藤奎将，吉田昌展，小川達也，大久保仁
電気学会論文誌B 126 巻 ( 11 ) 頁： 1164-1170 2006年
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Streamer and Leader Discharge Propagation Characteristics Leading to Breakdown in Electronegative Gases 査読有り
N.Hayakawa, K.Hatta, S.Okabe, H.Okubo
IEEE Trans. on Dielectrics and Electrical Insulation 113 巻 ( 4 ) 頁： 842-849 2006年
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Impulse and ac Partial Discharge Inception and Breakdown Characteristics of LN2/Polypropylene Laminated Paper Composite Insulation System 査読有り
H.Okubo, H.Kojima, F.Endo, K.Sahara, N.Hayakawa
IEEE Trans. on Dielectrics and Electrical Insulation 113 巻 ( 3 ) 頁： 664-669 2006年
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Common Insulating Properties in Insulating Materials 査読有り
S.Okabe, N.Hayakawa, H.Murase, H.Hama, H.Okubo
IEEE Trans. on Dielectrics and Electrical Insulation 113 巻 ( 2 ) 頁： 327-335 2006年
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Simulation of Electrical and Thermal Behavior of High Temperature Superconducting Fault Current Limiting Transformer (HTc-SFCLT) 査読有り
C.Kurupakorn, H.Kojima, N.Hayakawa, F.Endo, N.Kashima, S.Nagaya, M.Noe, H.Okubo
Journal of Physics: Conference Series 43 巻 頁： 950-953 2006年
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Partial discharge characteristics of inverter-fed motor coil samples under ac and surge voltage conditions 査読有り
N.Hayakawa, H.Okubo
IEEE Electrical Insulation Magazine 21 巻 ( 1 ) 頁： 5-10 2005年
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Impulse Partial Discharge Characteristics and Their Mechanisms under Non-uniform Electric Field in N2/SF6 Gas Mixtures 査読有り
N.Hayakawa, Y.Yoshitake, N.Koshino, T.Ueda, H.Okubo
IEEE Trans. on Dielectrics and Electrical Insulation 12 巻 ( 5 ) 頁： 1035-1042 2005年
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A Novel Technique for Partial Discharge and Breakdown Investigation Based on Current Pulse Waveform Analysis 査読有り
H.Okubo, N.Hayakawa
IEEE Trans. on Dielectrics and Electrical Insulation 12 巻 ( 4 ) 頁： 736-744 2005年
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Temperature Dependence of Critical Current at 4.2K–55K of Conduction-cooled Bi2212/Ag Wires 査読有り
H.Kojima, S.Noguchi, C.Kurupakorn, N.Hayakawa, M.Goto, N.Hirano, S.Nagaya, H.Okubo
IEEE Trans. on Applied Superconductivity 15 巻 ( 2 ) 頁： 2550-2553 2005年
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High voltage requirements and test of a 10 MVA superconducting fault current limiter 査読有り
M.Noe, K.-P.Juengst, S.Elschner, J.Bock, F.Breuer, R.Kreutz, M.Kleimaier, K.-H.Weck, N. Hayakawa
IEEE Trans. on Applied Superconductivity 15 巻 ( 2 ) 頁： 2082-2085 2005年
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Recovery Characteristics after Current Limitation of High Temperature Superconducting Fault Current Limiting Transformer (HTc-SFCLT) 査読有り
C.Kurupakorn, H.Kojima, N.Hayakawa, M.Goto, N.Kashima, S.Nagaya, M.Noe, K.-P.Juengst, H.Okubo
IEEE Trans. on Applied Superconductivity 15 巻 ( 2 ) 頁： 1859-1862 2005年
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Dielectric Characteristics of HTS Cables Based on Partial Discharge Measurement 査読有り
N.Hayakawa, M.Nagino, H.Kojima, M.Goto, T.Takahashi, K.Yasuda, H.Okubo
IEEE Trans. on Applied Superconductivity 15 巻 ( 2 ) 頁： 1802-1805 2005年
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CO2ガスのインパルス比と初期電子発生特性 査読有り
越野尚人，木下修，早川直樹，五島久司，岡部成光，森井浩，大久保仁
電気学会論文誌B 125 巻 ( 6 ) 頁： 568-574 2005年
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Partial Discharge Inception Characteristics of LN2/PP Laminated Paper Composite Insulation System for High Temperature Superconducting Cable 査読有り
N.Hayakawa, T.Kobayashi, M.Hazeyama, T.Takahashi, K.Yasuda, H.Okubo
IEEE Trans. on Dielectrics and Electrical Insulation 12 巻 ( 1 ) 頁： 166-174 2005年
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Electrical Insulation Characteristics at Cryogenic Temperature for High Temperature Superconducting Cables 査読有り
H.Okubo, N.Hayakawa
KIEE International Transactions on Electrophysics and Applications 4-C 巻 ( 1 ) 頁： 15-20 2004年
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Development of High Temperature Superconducting Fault Current Limiting Transformer (HTc-SFCLT) with Bi2212 Bulk Coil 査読有り
C.Kurupakorn, N.Hayakawa, H.Okubo, N.Kashima, S.Nagaya, M.Noe, K.-P.Juengst
IEEE Trans. on Applied Superconductivity 14 巻 ( 2 ) 頁： 900-903 2004年
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高温超電導限流変圧器（HTc-SFCLT）の開発 査読有り
クルパコン チャチャヴァン，早川直樹，鹿島直二，長屋重夫，大久保仁
電気学会論文誌B 124 巻 ( 10 ) 頁： 1193-1199 2004年
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棒－平板電極における空気および窒素ガス中インパルス部分放電および絶縁破壊特性 査読有り
斉藤 仁，森田啓一，吉川隆司，早川直樹，大久保仁
電気学会論文誌B 123 巻 ( 2 ) 頁： 169-174 2003年
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Electrical Insulation Performance under Thermal and Electric Combined Stress for Resistive Superconducting Fault Current Limiters 査読有り
N.Hayakawa, M.Noe, K.-P.Juengst, H.Okubo
IEEE Trans. on Applied Superconductivity 13 巻 ( 2 ) 頁： 1996-1999 2003年
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V-t characteristics for Partial Discharge Inception of High Temperature Superconducting Power Transmission Cables 査読有り
M.Hazeyama, N.Hayakawa, K.Matsuo, T.Masuda, H.Okubo
Physica C 372-376 巻 ( 3 ) 頁： 1551-1554 2002年
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V-t Characteristics of Partial Discharge Inception in Liquid Nitrogen/PPLP Composite Insulation System for HTS Superconducting Cable 査読有り
H.Okubo, M.Hazeyama, N.Hayakawa, S.Honjo, T.Masuda
IEEE Trans. on Dielectrics and Electrical Insulation 9 巻 ( 6 ) 頁： 945-951 2002年
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Impulse Partial Discharge and Breakdown Characteristics of Rod-Plane Gaps in N2/SF6 Gas Mixtures 査読有り
H.Saitoh, K.Morita, T.Kikkawa, N.Hayakawa, H.Okubo
IEEE Trans. on Dielectrics and Electrical Insulation 9 巻 ( 4 ) 頁： 544-550 2002年
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Partial discharge and breakdown mechanisms in ultra-dilute SF6 and PFC gases mixed with N2 gas 査読有り
H.Okubo, T.Yamada, K.Hatta, N.Hayakawa, S.Yuasa, S.Okabe
Journal of Physics D: Applied Physics 35 巻 ( 21 ) 頁： 2760-2765 2002年
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Investigation of Electric Insulation Diagnosis of Solid Insulators in GIS by Partial Discharge Current Pulse Waveform Analysis (PD-CPWA) 査読有り
H.Okubo, A.Matsushita, S.Watanabe, N.Hayakawa, T.Kumai
IEEE PES T&D 2 巻 頁： 925-930 2002年
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Development of Superconducting Fault Current Limiting Transformer (SFCLT) with the Functions of Fault Current Suppression and System Stability Improvement 査読有り
H.Okubo, H.Kagawa, N.Hayakawa, N.Kashima, S.Nagaya
IEEE PES T&D 1 巻 頁： 301-306 2002年
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Experimental Study on Superconducting Fault Current Limiting Transformer (SFCLT) for Fault Current Suppression and System Stability Improvement 査読有り
H.Kagawa, N.Hayakawa, N.Kashima, S.Nagaya, H.Okubo
Physica C 372-376 巻 ( 3 ) 頁： 1706-1710 2002年
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Partial Discharge Inception Characteristics under Butt Gap Condition in Liquid Nitrogen/PPLP Composite Insulation System for High Temperature Superconducting Cable 査読有り
M.Hazeyama, T.Kobayashi, N.Hayakawa, S.Honjo, T.Masuda, H.Okubo
IEEE Trans. on Dielectrics and Electrical Insulation 9 巻 ( 6 ) 頁： 939-944 2002年