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1991 Fiscal Year Final Research Report Summary

Basic Research for High-Performance Cryogenic Electrical Insulation System with Polar Polymeric Materials

Research Project

Project/Area Number 02805031
Research Category

Grant-in-Aid for General Scientific Research (C)

Allocation TypeSingle-year Grants
Research Field 電力工学
Research InstitutionToyohashi University of Technology

Principal Investigator

NAGAO Masayuki  Toyohashi Uni. of Technology Dept. of Electrical & Electronic Eng. Associate Professor, 工学部, 助教授 (30115612)

Project Period (FY) 1990 – 1991
KeywordsCryogenic Temperature / Electrical Insulation / Polar polymers / Electrical Breakdown / Space Charge
Research Abstract

Recently, developments of superconducting power apparatuses such as generators, cables and transformers, are promoted in many organizations in the world. These enhance the importance of the electrical insulation technology at cryogenic temperature. Under these situations, it is necessary to obtain much Knowledge of electric strengths and breakdown mechanisms of polymeric materials at cryogenic temperature.
At cryogenic temperature, electric strengths (Fb) of polar polymers are higher than of non-polar polymers. Further, they have generally higher mechanical strengths and their tan delta becomes allowable level in the cryogenic temperature region. These facts lead to the idea that polar polymers may be a good candidate for cryogenic electrical insulating materials. However, their breakdown mechanism, especially why Fb of polar polymers show negative temperature dependence in low-temperature region, has been scarcely clarified.
In this study, a new specimen is developed to measure intrinsic electric strengths of polymeric films at cryogenic temperature. The DC electric strengths of PVC film measured with this specimen have a peak around -80 ゚C and are almost constant below -120 ゚C, which is quite different from those already reported with recessed specimens. Since the recessed specimens made of the same PVC material give almost same temperature dependence of electric strength as that reported by the others, the above results are inherent to the jilm and are probably due to a difference in morphology of the material. The dependence of the electric strengths on both the rise rate of applied field and the prestressing showed that the electrical breakdown of polar polymers are apparently affected by a space charge effect at cryogenic temperature. These results show that the electrical breakdown of polar polymers in the low-temperature region can be interpreted by an electron avalanche breakdown and the space charge effect.

  • Research Products

    (8 results)

All Other

All Publications (8 results)

  • [Publications] M.Nagao,M.Kosaki,Y.Mizuno and M.Ono: "Distinctive Electrical Breakdown of Polar Polymeric Films in Cryogenic Temperature Region" Proc.7th Int.Symp.on High Uoltage Engineering. 2. 139-142 (1991)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 長尾,水野,小崎: "極低温領域における有極性高分子フィルムの絶縁破壊" 電気学会論文誌A. 112. (1992)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 福間,長尾,小崎: "過渡的空間電荷を考慮した熱的ー電子的複合破壊モデルの提案" 電気学会論文誌A. 112. (1992)

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] 水野,光山,飯塚,長尾,小崎: "極低温領域におけるエチレンプロピレンゴムの誘電・絶縁特性" 低温工学.

    • Description
      「研究成果報告書概要(和文)」より
  • [Publications] M. Nagao, M. Kosaki, Y. Mizuno & M. Ono: ""Distinctive Electrical Breakdown of Polar Polymeric Films in Cryogenic Temperature Region"" 7th International Symposium on High Voltage Engineering, Dresden , Germany. 139-142 (1991)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] M. Nagao, Y. Mizuno & M. Kosaki: ""Electrical Breakdown of Polar Polymeric Films in Cryogenic Temperature Region"" Trans. of IEE Japan. 112-A. (1992)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] M. Fukuma, M. Nagao, & M. Kosaki: ""Thermal and Electronic Composite Breakdown Model in Consideration of Transient Space Charge Formation"" Trans. of IEE Japan. 112-A. (1992)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Publications] Y. Mizuno, Y. Mitsuyama, M. Iizuka, M. Nagao & M. Kosaki: ""Dielectric and Electric Properties of Ethylene-propylene Rubber in Cryogenic Temperature Region"" Cryogenic Engineering.

    • Description
      「研究成果報告書概要(欧文)」より

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Published: 1993-03-16  

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