| 摘要 |
PURPOSE:To remove securely the accidental current of an on-load tap changer in the case of short-circuiting between taps without fear of breakdown of circuit and to suppress the transient recovery voltage caused by extinction of fuse arc by a method wherein a resistance element is inserted in parallel with a fuse. CONSTITUTION:At the change over operation of tap changer from an odd number side tap to an even number side tap, if each fuse is fused, the short-circuiting current between taps is removed, and the load current flows through the circuit consisting of tap selecting arm 2-input terminal 4- fixed contact 14-movable contact 15-current-limiting resistor R1-resistance contact C-output terminal 8, and flows through the circuit remained by failure of breaking, of vacuum breaker VS consisting of selecting arm 2-input terminal 4-resistance element 20-fixed contact 6-movable contact 7-switch VS-terminal 8. Then the vacuum breaker VS is made to close and a contact C is made to open. The load current is transferred to the circuit consisted of selecting arm 2-terminal 4- element 20-contact 6-contact 7-switch VS-terminal 8. At last by changing over a movable contact exclusive use for current feeding 11 to an even number side fixed contact exclusive use for current feeding 10, the circuit consisting of selecting arm 2-terminal 4-contact 10-contact 11-terminal 8 is formed and changing over is completed. Therefor irrelevant to the fused place of fuse, the change over operation is completed without an instantaneous break down of load current circuit. |
