研究者詳細 - 兒玉　直人

論文 - 兒玉　直人

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量子化学計算を併用した高温消弧ガス特性の解析招待有り

兒玉直人・横水康伸

令和5年電気学会全国大会講演論文集 2023年3月

Analysis of Arc Characteristics for Improvement of Power Protection Device Performance 招待有り査読有り国際誌

Kodama N

Proceeding - ELTICOM 2022: 6th International Conference on Electrical, Telecommunication and Computer Engineering 2022 頁： 14 - 17 2023年2月

担当区分：筆頭著者,　最終著者,　責任著者記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：Proceeding - ELTICOM 2022: 6th International Conference on Electrical, Telecommunication and Computer Engineering 2022

Power protection devices such as gas circuit breaker and current limiting fuse are key component for safety usage of electric system. During fault current breaking process high temperature arc can be formed inside these devices. The arc breaking is neccessary to achieve current interruption. High temperature gas properties of arc is very important factor to simulate the arc breaking process and to design the protection device. This paper briefly introduces calculation procedure of gas properties and discuss the importance of gas property analysis using the arc inside the limiting fuse as typical example. In addition, it is also introduced the relationship between gas property analysis and the quentum chemical calculation as recent trends.

DOI： 10.1109/ELTICOM57747.2022.10038272

Scopus

Theoretical calculation of current commutation process and residual current during contact sliding movement - Application of High Resistivity Material to Fixed Contact Rear Part-

Hiroumi Kawabata, Yasunobu Yokomizu, Naoto Kodama, Kanta Watanabe, Fukutsuka Takashi

Proceeding of 13th International Workshop on High Voltage Engineering(IWHV2022) 2022年11月

DC Arc Column Resistance Rise with Silicone Resin Painted on Copper Fuse-Element in Silica-sand Filling Space

Waku Takenaka, Naoto Kodama, Kaito Hasegawa, Yasunobu Yokomizu, Hironori Shimizu

Proceeding of 13th International Workshop on High Voltage Engineering(IWHV2022) 2022年11月

Simplified analysis of short-circuit current for hybrid AC/DC delivery system

Mir Sayed Shah Danish, Mikimasa Iwata, Yasunobu Yokomizu, Naoto Kodama

Proceeding of 13th International Workshop on High Voltage Engineering(IWHV2022) 2022年11月

Reaction Products in SF6 Multi Mixture with C2F4-BN and Cu Vapor Decomposition at 300-3000 K: Approach to Dielectric Breakdown Property Evaluation

YOKOMIZU Yasunobu, KODAMA Naoto, URAI Hajime, TERADA Masanao, KURODA Mami

Proceeding of 13th International Workshop on High Voltage Engineering(IWHV2022) 2022年11月

Experiment on DC Arc Quenching using Ablation of Polymer Narrow-Section Arranged around Fuse Element

Kodama Naoto, Yokomizu Yasunobu, Takenaka Waku, Nakamura Kanata, Tozaki Shinsuke, Iwata Mikimasa, Danish M. S. S.

Proceeding of the 13th International Workshop on High Voltage Engineering(IWHV2022) 2022年11月

Arc resistance increasing during DC interruption using SiO2/Si3N4 mixture powder as arc interruption medium 査読有り

Naoto Kodama, Yaunobu Yokomizu, Waku Takenaka, and Kaito Hasegawa

Proceeding of the 75th Annual Gaseous Electronics Conference/11th International Conference on Reactive Plasmas 2022年10月

Trial application of Si3N4 powder as alternative arc interruption medium for DC interruption 査読有り

Naoto Kodama, Yokomizu Yasunobu, Waku Takenaka, and Kaito Hasegawa

Proceeding of the 5th International Union of Materials Research Societies/International Conference of Young Researchers on Advanced Materials 2022年8月

代替ガスを用いたアーク消弧過程で生じる化学種間の相互作用ポテンシャル -量子化学計算を用いた輸送特性の高精度導出に向けて

笠井豪, 兒玉直人, 横水康伸, 杉田武弘, DANISH M. S. S, 岩田幹正

電気学会研究会資料放電・プラズマ・パルスパワー/静止器/開閉保護合同研究会 2022年7月

電気接点の摺動・開離過程における電流転流プロセスおよび残留電流の理論計算 --ブラシ後部への高抵抗材適用による残留電流の低減--

川端大海,　横水康伸,　兒玉直人,　渡邉幹太,　福塚隆司

電気学会研究会資料放電・プラズマ・パルスパワー/静止器/開閉保護合同研究会 2022年7月

高温CO2/O2/CF3OH混合消弧ガスにおける凝縮相炭素の無生成とO2残存：温度300 Kおよび3000 Kにおける耐電圧特性

兒玉直人, 横水康伸, 杉田武弘, 中村泰規, 佐藤基宗

電気学会研究会資料放電・プラズマ・パルスパワー/静止器/開閉保護合同研究会 2022年7月

High Temperature Gas Properties for Arc Formed in DC Fuse Using Silica-Sand 査読有り

Naoto Kodama, Yasunobu Yokomizu, Waku Takenaka, Kaito Hasegawa

Proceeding of the International Council on Electrical Engineering Conference 2022 2022年7月

DC Arc Interruption Experiment using Arrangement of Polymer-Narrow Section inside Fuse-Case Filled with Silica-Sand

Naoto Kodama, Yasunobu Yokomizu, Waku Takenaka

Proceeding of the 6th International Conference on Electric Power Equipment -Switching Technology- 2022年3月

Dielectric Breakdown Properties for High Temperature HFO−1234yf/CO2 Gas Mixture with Consideration of Predominant Molecular Products at 300−3000 K

Takehiro Sugita, Yasunobu Yokomizu, Naoto Kodama, Motohiro Sato, Yasunori Nakamura

Proceeding of the 6th International Conference on Electric Power Equipment -Switching Technology- 2022年3月

Arrangement of Silicone Flat Plate in Silica Sand Filling Space for DC Arc Resistance Rise

Waku Takenaka, Naoto Kodama, Yasunobu Yokomizu, Koya Nakamura, Hironori Shimizu

Proceeding of the 6th International Conference on Electric Power Equipment -Switching Technology- 2022年3月

DC Arc Interruption Experiment using Arrangement of Polymer-Narrow Section inside Fuse-Case Filled with Silica-Sand

Kodama, N; Yokomizu, Y; Takenaka, W

2022 6TH INTERNATIONAL CONFERENCE ON ELECTRIC POWER EQUIPMENT - SWITCHING TECHNOLOGY (ICEPE-ST) 頁： 28 - 33 2022年

記述言語：日本語出版者・発行元：ICEPE-ST 2022 - 2022 6th International Conference on Electric Power Equipment - Switching Technology

It is strongly desired for DC fuse that a compatibility of high arc resistance(rarc) during a DC arc interruption and high insulation resistance(Rins) after the DC arc interruption. This paper describes a trial experiment of DC arc interruption under following conditions. (1) Copper(Cu)-element arrangement in silica-sand filling space(designated as "S-wo"), (2) Arrangement of a polymer fuse-case filled with the silica-sand around the Cu-element(designated as "S-CaseA"), and (3) Arrangement of a polymer narrow-section around an arc-ignition point of Cu-element in the silica-sand filled fuse-case(designated as "S-CaseB"). The damping DC with a prospective peak of 1000 A was energized to the Cu-element to ignite the DC arc. As a result, the compatibility of high rarc and high Rins was successfully achieved only under the S-CaseB condition. These high rarc and high Rins can be interpreted from the shrinking of arc conductive diameter by the silica-sand filled inside the fuse-case and formation of insulation layer by the ablation of the polymer-narrow section.

DOI： 10.1109/ICEPE-ST51904.2022.9757094

Web of Science

Scopus

Dielectric Breakdown Properties for High Temperature HFO-1234yf/CO<sub>2</sub> Gas Mixture with Consideration of Predominant Molecular Products at 300-3000 K

Sugita, T; Yokomizu, Y; Kodama, N; Nakamura, Y; Sato, M

2022 6TH INTERNATIONAL CONFERENCE ON ELECTRIC POWER EQUIPMENT - SWITCHING TECHNOLOGY (ICEPE-ST) 頁： 88 - 92 2022年

記述言語：日本語出版者・発行元：ICEPE-ST 2022 - 2022 6th International Conference on Electric Power Equipment - Switching Technology

With regard to HFO-1234yf mixed with CO2 as a buffer gas, this paper describes dielectric breakdown properties such as an electron attachment coefficient and a critical reduced electric field strength Ecr/N at 300-3000 K. First, this paper covers predominant molecular products through thermal dissociation and combination reactions for 20%HFO-1234yf/80%CO2 gas mixture. Secondly, dielectric breakdown properties of the mixture in consideration of the predominant gaseous molecular products are described to show that Ecr/N is 87-100 Td at 300-3000 K.

DOI： 10.1109/ICEPE-ST51904.2022.9757102

Web of Science

Scopus

DC Arc Resistance Rise by PMMA Cylinder Ablation with Arc Shrinking in Silica Sand Filling Space 査読有り

Kodama, N; Nakamura, K; Yokomizu, Y; Takahashi, A; Yamamura, N

IEEJ TRANSACTIONS ON ELECTRICAL AND ELECTRONIC ENGINEERING 16 巻 ( 12 ) 頁： 1679 - 1686 2021年12月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：IEEJ Transactions on Electrical and Electronic Engineering

Concerning DC arc quenching phenomenon in silica sand filling space, we have proposed a new method for raising an arc column resistance (rcol) by use of polymer-material arrangement. This paper reveals physical factors for rcol rise on the bases of experimental results using the following cylinders made of: (i) Quartz (SiO2) and (ii) PMMA ((C5H8O2)n) with various inner diameters ϕ. For ϕ = 2 mm case, rcol measured for a PMMA cylinder arrangement indicated higher rcol at low current region, while almost same rcol around current peak. For ϕ = 3 mm case, rcol for the PMMA cylinder was lower than rcol for the quartz case at high current region, while almost comparable between these conditions at low current region. For ϕ = 5 mm case, rcol were almost same during the arc quenching process. To discuss the effect of the rcol rise, the followings were also performed: (i) observation of cylinders after arc quenching and (ii) calculation of the electron density of SiO2/Cu or PMMA/SiO2 mixture vapors. It is concluded that, at high current region, rcol can increase due to the shrinking of the arc conductive diameter caused by the cylinder hole and the silica sand filled inside the cylinder hole. On the other hand, the admixing of the PMMA ablation vapor increases rcol at low current region in the present experiment. © 2021 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC.

DOI： 10.1002/tee.23462

Web of Science

Scopus

珪砂を用いた直流アーク消弧過程で生じる高温ガスの特性

兒玉直人，横水康伸，中村晃也，竹中湧，清水宏紀

電気学会研究会資料放電・プラズマ・パルスパワー/開閉保護/高電圧合同研究会 2021年11月

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