| 摘要 |
PROBLEM TO BE SOLVED: To provide a DC current cut-off device, with little conduction loss, capable of reducing installation capacity and footprint, and capable of reducing a construction cost of a building and a foundation.SOLUTION: The DC current cut-off device includes: a mechanical contact breaker; a semiconductor breaker; and a commutation device. The mechanical contact breaker includes: a mechanical contact with which a high breakdown voltage contact and a current breaker contact are connected in series; and a bushing for electrically connecting both terminals of the mechanical contact and a DC transmission system by connecting to a pressure container having the same potential as a ground potential. The commutation device is connected in parallel to at least the high breakdown voltage contact out of the high breakdown voltage contact and the current breaker contact and connected in series with the semiconductor breaker. By making the mechanical contact to be an open circuit to make the semiconductor stack to be in an energization state when a fault of the DC transmission system occurs, a current flowing through the mechanical contact breaker is made to be temporarily zero by the commutation device, so that the fault current is commutated from the mechanical contact breaker to the semiconductor breaker and the semiconductor stack is made to be in a cut-off state after the commutation. Thus, the fault current is cut-off.SELECTED DRAWING: Figure 1 |
