Model Development for Estimating Recovery Time of Fault Current Limiters by Elucidation of Electrical-Thermal Phenomena in High-Temperature Superconducting Tapes

2023 Fiscal Year Final Research Report

• Project/Area Number: 22K20434
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Multi-year Fund
• Review Section: 0302:Electrical and electronic engineering and related fields
• Research Institution: Tokyo University of Science, Yamaguchi
• Principal Investigator: Yuki Kohei 山陽小野田市立山口東京理科大学, 工学部, 助教 (00963563)
• Project Period (FY): 2022-08-31 – 2024-03-31
• Keywords: 沸騰熱伝達 / ポーラス体 / 液体窒素 / 急冷 / 超伝導限流器 / 超伝導線材

Outline of Final Research Achievements

In this study, structures of porous stabilizer utilized for superconducting tapes was investigated for the realization of superconducting fault current limiters. First, we proposed a boiling/evaporation model in the porous stabilizer. As a result, the relative error between this model and experimental result was approximately 10%, indicating that coolant retention is an important role of the porous stabilizer.
Further, to clarify the structure of the porous stabilizer that is effective in suppression of hot spots, propagation behaviors of the normal-state region was evaluated by an electrical and thermal coupling analysis. After the analysis, the effectiveness of porous stabilizer was experimentally evaluated. The results shows that the porous stabilizer can instantly expand the normal-state region of superconducting tape and suppress the occurrence of hot spots.

Free Research Field

熱工学、超伝導工学

Academic Significance and Societal Importance of the Research Achievements

超伝導限流器は電力系統での短絡事故電流を抑制する役割を持ち，既存機器の交換が不要なため費用対効果が大きいが未だ実現には至っていない．本研究では実現の大きな障壁となっている超伝導線材の冷却特性に着目し，ポーラス安定化材により従来成し得なかった「冷却性能の向上」と「超伝導線材のホットスポットの抑制」を同時に達成可能な指針を示している．また，ポーラス体内の沸騰という複雑な現象をモデル化することで冷却性能の向上に対する重要因子の抽出に成功している．
上記の知見を超伝導限流器だけでなくポーラス体を利用したCPU冷却やヒートパイプなどの既存機器にも応用することで更なる性能向上が見込めると期待できる．