Micro dot electrodes with dissimilar metals for arc-free kA DC current interruption

2020 Fiscal Year Final Research Report

• Project/Area Number: 19K21964
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 21:Electrical and electronic engineering and related fields
• Research Institution: Tokyo Institute of Technology
• Principal Investigator: Yasuoka Koichi 東京工業大学, 工学院, 教授 (00272675)
• Project Period (FY): 2019-06-28 – 2021-03-31
• Keywords: 電気接点 / 溶融ブリッジ / アーク / 高融点材料 / 可変抵抗

Outline of Final Research Achievements

This study aimed to realize a kA-class arc-free technology in a hybrid DC circuit breaker that consisted of mechanical contacts and semiconductor devices. Since the arc is generated when the temperature of the contact surface exceeds a boiling temperature, we proposed mounting of tungsten material, enhancing of heat dissipation using copper-based tungsten contacts, and 4-block structure to disperse the contact current.
Numerical simulation showed that the arc-free current was 450A for the copper-based tungsten contacts, but was increased to 800 A for the 4-block-structure contacts of copper-based tungsten. The arc free current in experiments was limited to 400 A regardless of the division number. Thus, a variable resistance contacts was newly developed using copper, copper-carbon, and carbon materials. In conclusion, this configuration is expected to increase the arc-free current.

Free Research Field

高電圧プラズマ工学

Academic Significance and Societal Importance of the Research Achievements

CO2を排出しない再生可能エネルギーの大量導入にむけて，蓄電装置を含めたｋA級の直流システムの構築が急務である。ただし直流は交流と異なり電流ゼロ点がないため，機械接点ではアーク継続や電磁ノイズ発生の課題があり，これに替わって半導体パワーデバイスが利用される。ただし半導体デバイスは定常時の電力損失が大きい欠点がある。
これらの課題を解決する手段として機械接点と半導体を組み合わせたハイブリッド直流遮断器が提案されているが，現状では短時間アーク発生の課題が残る。本研究は新たな接点構造によりアークフリーの直流ハイブリッド遮断器を研究するもので，社会要請に合致している。