1996 Fiscal Year Final Research Report Summary
Study on High Temperature Superconducting Power Device Due to Dynamic Control of Magnetic Shield Functions
| Project/Area Number |
07455115
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
電力工学・電気機器工学
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| Research Institution | HOKKAIDO UNIVERSITY |
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Principal Investigator |
ONISHI Toshitada Hokkaido Univ., Fac.of Eng., Pro., 工学部, 教授 (10261330)
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| Co-Investigator(Kenkyū-buntansha) |
ITO Yuzou Hokkaido Univ., Fac.of Eng., Instructor, 工学部, 助手 (50001269)
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| Project Period (FY) |
1995 – 1996
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| Keywords | Superconducting Fault Current Limiter / High Temperature Superconductor / Magnetic Shield / Power Device |
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| Research Abstract |
The high Tc superconducting fault current limiter and the superconducting power device were studied from a view point of dynamic control in the magnetic shielding functions.
In the research on the magnetic shield type superconducting fault current limiter, an active control method in which the field winding for control is wound on the superconducting shield tube in a toroidal fashion and the superconducting properties will be controlled dynamically by applying the ac magnetic field of frequencies of around a few kHz to the one has been proposed. The fault corrent limiters with such an active control coil were fabricated and the various characteristics were studied experimentally and by computer simulation.
It was made clear that the flux flow resistivity would be considerably increased by applying the ac magnetic fields of frequencies of around a few kHz and accordingly the current limiting impedance would become fairly large as compared with the case without an active control. This fact indicates that although the flux flow resistivity was thought to be controlled only by magnetic field and/or temperature so far, it will also depend on the magnitude of the frequency of ac magnetic field. The reason why the flux flow resistivity will be affected by the frequency of ac field is not clarified yet, but the phenomenon will be very useful for the improvement in performances of the fault corrent limiters.
As for the superconducting power devices, the dynamic behaviors of magnetic flux in the iron core were investigated by using the device consisted of the thin film superconducting discs and the closed circuit iron core. It was clarified that the magnetic flux in the iron core would be controlled by the superconducting to normal conducting transition of the thin film.
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