| 摘要 |
PROBLEM TO BE SOLVED: To increase impedance to permit current limiting action if a fault occurs and reduce the number of rectifying elements, by choosing an opening/ closing interval of an interrupting means for linkage recovery and a current attenuation time constant of a direct-current reactor in specific relation. SOLUTION: After a breaker 31 is opened, a current reflows in parallel circuits U1, U2 due to discharge of magnetic field energy accumulated in direct- current reactors L1, L2. If the breaker 31 is opened due to occurrence of a fault, however, breakers advancing higher up to the three-line, for example, are opened for the purpose of fault detection, and thereafter sequentially closed again. Therefore, to close the breaker 31 again, the maximum current IDCMAX at the time of the current limiting action of the direct-current reactors L1, L2 niust have been attenuated to the level of the current IDCO in the steady state when the breaker 31 is closed again. In other words, a relation expressed as IDCO>=IDCMAX.exp (-To/τ) must hold in terms of opening/closing interval for linkage recovery, and a current attenuation time constant τ=To/ln(IDCMAX/IDCO) is chosen. |
