| 摘要 |
PURPOSE: To provide a method for disconnecting an uninterruptible power supply unit, which has failed, of an uninterruptible power supply system provided with a plurality of uninterruptible power supply units which are operated by a parallel redundancy system. CONSTITUTION: When it is judged by an upper/lower limit discriminator 21 that the effective cross current component computed for the cross current from a UPS 10 by means of an effective cross current component computing element 20 reaches an upper or lower limit, the UPS 10 is disconnected by comparing the internal frequency of the UPS 10 with a bus frequency and reference frequency. Therefore, the UPS 10 can be quickly disconnected. |
