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Mechanisms of dielectric breakdown of ljquid coolants under quench condition and estimation of withstand voltage

Research Project

Project/Area Number 08455136
Research Category

Grant-in-Aid for Scientific Research (B)

Allocation TypeSingle-year Grants
Section一般
Research Field 電力工学・電気機器工学
Research InstitutionKYUSHU UNIVERSITY

Principal Investigator

HARA Masanori  Kyushu University, Graduate School of Information Science and Electrical Engineering, Professor, 大学院・システム情報科学研究科, 教授 (30039127)

Co-Investigator(Kenkyū-buntansha) IMASAKA Kiminobu  Kyushu University, Graduate School of Information Science and Electrical Enginee, 大学院・システム情報科学研究科, 助手 (40264072)
SUEHIRO Junya  Kyushu University, Graduate School of Information Science and Electrical Enginee, 大学院・システム情報科学研究科, 助教授 (70206382)
Project Period (FY) 1996 – 1997
Project Status Completed (Fiscal Year 1997)
Budget Amount *help
¥7,500,000 (Direct Cost: ¥7,500,000)
Fiscal Year 1997: ¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 1996: ¥6,200,000 (Direct Cost: ¥6,200,000)
KeywordsSuperconducting Magnet / Quench / Insulation Design / Liquid Coolant / Thermal Bubble / Gradient force / Area Effect / Pool-boiling He-cooled / 超伝動コイル / 極低温 / 部分放電 / 密閉ボイド / 電界放出 / 放電電荷量
Research Abstract

In this study, establishment of electrical insulation technique and development of insulation trust of a superconducting magnet were aimed at. Boiling phenomena of liquid nitrogen and helium used for coolant of the magnet under high electric field was investigated. Moreover, mechanism of breakdown of those liquid coolant and characteristics of withstand voltage were discussed. Obtained results were summarized as follows.
1.Electrical insulation design of pool-boiling He-cooled superconducting coils
Insulation design procedure was proposed and applied to a small SMES.It was found that the main parameters determining insulation space were delay time of quench protection switch, initial coil current, coil inductance, and conductor geometry and size.
2.Bubble behavior in liquid coolant under quench condition
Bubble behavior under high electric fields was studied theoretically and experimentally. The results showed that bubble motion was influenced mainly by an electrical gradient force acting on it. Then it is very important to pay attention to a setting of the gasp length in order to get a passage of the coolant under quench condition.
3.Breakdown characteristics of LNi and LHe including a superfluid condition were investigated statistically.
It was shown that the statistical characteristic of breakdown were well fitted to Weibull distribution based on weak-link theory and area effect was dominant rather than volume effect for size effect of electrodes to the breakdown characteristics.

Report

(3 results)
  • 1997 Annual Research Report   Final Research Report Summary
  • 1996 Annual Research Report
  • Research Products

    (24 results)

All Other

All Publications (24 results)

  • [Publications] 末廣 純也: "飽和超流動ヘリウム中の絶縁破壊特性に及ぼす液体温度と電極サイズの影響" 電気学会論文誌A. 117・7. 691-696 (1997)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] 松浦 俊輔: "液体窒素中の気泡運動に対するギャップ長の影響に関する理論的検討" 電気学会論文誌A. 117・8. 881-888 (1997)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] 高野 浩二: "液体窒素中の熱気泡トリガー絶縁破壊に与える絶縁フィルムの影響" 電気学会論文誌A. 117・10. 1026-1033 (1997)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] 見山 雅英: "超伝導コイルのクエンチ等価環境下における常温ヘリウムガスの短ギャップ絶縁破壊特性" 電気学会論文誌A. 116・7. 628-634 (1996)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] J.Suehiro: "Size Effect and Statistical Characteristics of dc and Pulsed Brekdown of Liquid Helium" IEEE Trans.on DEI. 3・4. 82-89 (1996)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] Z.C.Wang: "Bubble Behavior and Breakdown characteristics in LHe under Simulaating Quench Condition of S.C.Magnet" Trans.IEEE of japan. 116・10. 873-880 (1996)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] J.Suehiro: "Influence of Temperature and Electrode Size on Breakdown Characteristics in Saturated Superfluid Helium" T.IEE Japan. Vol.117-A,No.7. 691-696 (1997)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] S.Matsuura: "Analytical Study on Influence of Gap Geometry upon Behavior of Thermally-Induced Bubble in Liquid Nitrogen" T.IEE Japan. Vol.117-A,No.8. 881-888 (1997)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] K.Takano: "Effect of a Thin Insulation Film on Thermal Bubble-Triggered Breakdown Phenomena in Liquid Nitrogen" T.IEE of Japan. Vol.117-A,No.10. 1026-1033 (1997)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] M.Miyama: "Short Gap Breakdown Characterisitics of Helium Gas at Room Temperature under Equivalent Condition of Superconducting Coil Quenching" Trans.IEE of Japan. Vol.116-A,No.7. 628-634 (1996)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] J.Suehiro: "Size Effect and Statistical Characteristics of dc and Pulsed Breakdown of Liquid Helium" IEEE Trans.on DEI. Vol.3, No.4. 507-514 (1996)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] Z.C.Wang: "Bubble Behavior and Breakdown Characteristics in LHe under Simulating Quench Condition of S.C.Magnet" Trans.IEE of Japan. Vol.116-A,No.10. 873-880 (1996)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] 鶴 信一郎: "密閉ボイドにおける部分放電の機構と特性に及ぼす温度の影響" 電気学会放電研究会. 37-42 (1997)

    • Related Report
      1997 Annual Research Report
  • [Publications] 末廣 純也: "飽和超流動ヘリウム中の絶縁破壊特性に及ぼす液体温度と電極サイズの影響" 電気学会論文誌A. 117・7. 691-696 (1997)

    • Related Report
      1997 Annual Research Report
  • [Publications] S.Tsuru: "Partial Discharge Characteristics in Artificial Air-Filled Voids Immersed in Liquid Nitrogen" Proc.of 5th ICPADM. 228-231 (1997)

    • Related Report
      1997 Annual Research Report
  • [Publications] K.Takano: "Thermal Bubble-Triggered Breakdown of a Plane-to Cylinder Electrode Partially Covered with Thin Insulation Film in Liquid Nitrogen" Proc.of ISH. 2. 35-38 (1997)

    • Related Report
      1997 Annual Research Report
  • [Publications] 松浦 俊輔: "液体窒素中の気泡運動に対するギャップ長の影響に関する理論的検討" 電気学会論文誌A. 117・8. 881-888 (1997)

    • Related Report
      1997 Annual Research Report
  • [Publications] 高野 浩二: "液体窒素中の熱気泡トリガー絶縁破壊に与える絶縁フィルムの影響" 電気学会論文誌A. 117・10. 1026-1033 (1997)

    • Related Report
      1997 Annual Research Report
  • [Publications] M.Hara: "Insulation Design of Pool-boiling He-cooled Superconducting Coils" IEEE Trans.on DEI. 4・6. 792-799 (1997)

    • Related Report
      1997 Annual Research Report
  • [Publications] 高野 浩二: "熱気泡が存在する液体窒素中の絶縁破壊機構に対する絶縁テープの影響" 電気学会放電研究会. 127-135 (1996)

    • Related Report
      1996 Annual Research Report
  • [Publications] 鶴 信一郎: "液体窒素温度における密閉ボイドの部分放電特性" 電気学会放電研究会. 145-154 (1996)

    • Related Report
      1996 Annual Research Report
  • [Publications] 生澤 宏彰: "極低温窒素ガス中及び熱気泡存在時の液体窒素中における部分放電特性" 電気学会放電研究会. 13-18 (1997)

    • Related Report
      1996 Annual Research Report
  • [Publications] 原 雅則: "浸漬冷却超伝導コイルの絶縁設計法" 電気学会論文誌B. 116-B・7. 777-784 (1996)

    • Related Report
      1996 Annual Research Report
  • [Publications] 見山 雅英: "超伝導コイルのクエンチ等価環境下における常温ヘリウムガスの短ギャップ絶縁破壊特性" 電気学会論文誌A. 116-A・7. 628-634 (1996)

    • Related Report
      1996 Annual Research Report

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Published: 1996-04-01   Modified: 2016-04-21  

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