679 / 2017-06-01 11:13:57

Possibility of Semiconductor Circuit Breaker for DC transmission

DC transmission has a lot of merits compared with AC transmission. For example, the cost of the construction and the equipment is less than that of the AC transmission system. Besides, more energy can be transmitted in DC transmission lines. Recently, multi-terminal transmission lines are required urgently. For that purpose, the reliable DC transmission circuit breakers must be developed. As we all know, there is no natural current zero in DC power supply systems. When a fault current begins, a large current will flow through the system. Thus a skillful DC interruption process is needed to cut the fault. The existence of the reliable DC circuit breakers ensures the successful interruption process and can protect the DC transmission systems. In this paper a superconducting fault current limiter (SFCL) has been introduced which can limit the current to a small current level immediately after the fault occurs. And then, the limited current needs to be interrupted by DC circuit breakers. In the paper, two different kinds of DC circuit breakers were introduced. One is a SF6 gas breaker which has a transverse magnetic field (TMF) inside the chamber. The other is a SiC semiconductor breaker. A SF6 gas breaker with TMF can decrease arcing time, however, the arcing time is still very long. While a semiconductor circuit breaker has a lot of series and parallel connections which will increase the cost.