DC CIRCUIT BREAKER

PROBLEM TO BE SOLVED: To provide a small size DC circuit breaker which is disposed at a node of plural DC current power transmission lines capable of swiftly shutting off a fault current at a low cost by reducing the number of semiconductor switching elements.SOLUTION: The DC circuit breaker includes: mechanical operate contact circuit breakers 21, 22 and 23 on each of DC current power transmission lines 11, 12 and 13. Opposite side lines 11a, 12a and 13a, each of which extends from independent mechanical operate contact circuit breakers 21, 22 and 23, are connected to each other at a node j via commutation circuits 31 and 32. Each of the commutation circuits 31 and 32 is constituted of a semiconductor breaker 4 and an H bridge group circuit which are serially connected to each other, and each of the commutation circuits 31 and 32 is a bi-direction commutation circuit for commutating the currents flowing on the mechanical operate contact circuit breakers 21, 22 and 23.SELECTED DRAWING: Figure 1 【課題】複数の直流送電線の結合点において、事故電流を高速に遮断可能であり、且つ半導体スイッチング素子数を低減して、低コストで小型の直流電流遮断装置を提供する。【解決手段】各直流送電線１１，１２，１３の線路上にそれぞれ機械接点式電流断路器２１，２２，２３を備える。異なる機械接点式電流断路器２１，２２，２３から延びる結合点ｊとの反対側線路１１ａ，１２ａ，１３ａ同士を転流回路３１，３２によって接続する。転流回路３１，３２は、半導体遮断器４とＨブリッジ群回路とが直列接続されて構成され、機械接点式電流断路器２１，２２，２３に流れる電流を転流させる双方向転流回路である。【選択図】図１