| 摘要 |
PURPOSE:To secure redundancy of power transmission and distribution with an inexpensive cost by a method wherein cables in normal service for respective phases and at least a preliminary cable for one phase are provided and when trouble is caused in either one phase among the working cables, the preliminary cable is employed instead of said cable in trouble. CONSTITUTION:Faulty phase discriminating relays 3 are installed at both ends of a cable. When trouble is caused in a first phase, for example, the relay contacts of first phases of the faulty phase discriminating relays 3, 3 are closed. The normal-preliminary switching of switching devices 1 at both ends of the cable is effected after confirming the trouble in the phase by the faulty phase discriminating relays 3, 3 at both ends of the cable. For your reference, the faulty phase discriminating relays are provided at both ends of a section, in which both of the normal and preliminary cables are laid, however, the relays may be installed at only the end of the power source side of the cables. |
