2002 Fiscal Year Final Research Report Summary
Research on Advanced Superconducting Fault Current Limiter with Both Quick Current Limiting Function and Superconducting Recovery Characteristics
| Project/Area Number |
13450108
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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. Grad. School of Eng., Prof., 大学院・工学研究科, 教授 (10261330)
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| Co-Investigator(Kenkyū-buntansha) |
SASAKI Ken-ichi Hokkaido Univ. Grad. School of Eng., Inst., 大学院・工学研究科, 助手 (70322831)
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| Project Period (FY) |
2001 – 2002
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| Keywords | Superconducting Fault Current Limiter / High Temperature Superconductor / Fault Current Limitation / Superconducting Recovery / Magnetic Shield / Liquid Nitrogen Cooling |
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| Research Abstract |
The needs for fault current limiters are increased in order to establish a reliable and flexible power system. The research and development on various types of fault current limiters have been conducted especially since the discovery of the high temperature superconductor. A magnetic shield type superconducting fault current limiter (denoted as MSFCL) is thought to be one of the promising candidates for the practical one. The superconducting magnetic shielding body for MSFCL has to be heated up quickly over the critical temerature in order to produce large current limiting impedance. It is, however, difficult to heat it up to such a high temperature in the early stage of current limiting action.
The authors proposed a high-performance MSFCL which would have functions to solve such a problem. One of the features is that the superconducting magnetic shielding body will be heated up automatically and quickly after a short circuit failure occurs. It will also be recovered to superconducting state in a short period of time when the fault is cleared. Those characteristics were revealed by computer simulations. The researches on the thermal and current limiting characteristics were conducted experimentally for the MSFCL with the proposed structure to verify such characteristics in this project. It was revealed that the superconductor was automatically heated up over the critical temperature T__c within around 1 cycle after a fault occurs when the voltage applied to the current limiting coil is set over an appropriate value which corresponds to the distribution power line voltage (6.6 kV). The superconducting recovery characteristics were also studied experimentally. It was shown that the fault current limiter will be recovered quickly into a superconducting state within 1 s after the line current becomes zero. The design criterion of cooling structure for fast superconducting recovery was also shown.
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