Development of DC-current-limiting circuit-breaker with superconducting fault current limiter

Many of natural energy power generations create electricity of DC current. On the other hand, many of load sides consume DC converted from AC. Therefore, conversion loss and CO₂ emission may be able to reduce by adopting DC distribution. However, the interruption on DC current becomes difficult because zero point which exists in alternate current doesn´t exist. To achieve the interruption becomes a technical problem. We had investigated combination of a superconducting fault current limiter (SFCL) and breaker in liquid nitrogen (LN₂) before. As the result, the interruption performance in LN₂ is excellent compared with that of air. In this paper, we investigated characteristic of SFCL at the series-parallel connection and puffer type DC breaker in LN₂.