Applications of DC Breakers and Concepts for Superconducting Fault-Current Limiter for a DC Distribution Network

Many alternative energy power generation systems create DC electricity. Also, many devices consume DC converted from AC. Therefore, it may be possible to reduce conversion losses and CO₂ emissions by adopting DC distribution. We assume that superconducting cables will be used for dc distribution because their electrical resistance is almost zero. However, if a superconducting cable is adopted, it is of great concern that if an excessive current flows because of, for instance, a short circuit, then there is a possibility that this current cannot be interrupted by a circuit breaker alone. We propose that the fault current be limited by a superconducting fault-current limiter (SFCL) and that this limited current is then interrupted by a DC circuit breaker. In this paper, we have separately investigated the SFCL and DC breaker and their use in combination.