Rapid Cutoff Device and Operation Method for SCR AC Switches

摘要

A rapid cutoff device includes a thyristor AC switch for supplying an AC current from a first AC circuit to a second AC circuit. A serially-connected circuit of a first switch and a first capacitor parallel-connects with the first AC circuit. A serially-connected circuit of a second switch and a second capacitor parallel-connects with the second AC circuit. When cutting off the thyristor AC switch, the first switch is operated to conduct the first capacitor in a first direction for the AC current charging to the first capacitor, alternatively, the second switch is operated to conduct the second capacitor in a second direction for the AC current charging to the second capacitor, thereby lowering a current in the thyristor AC switch approaching a zero value and thus rapidly cutting off it.

主权项

1. A rapid cutoff device for SCR AC switches comprising:
a thyristor AC switch electrically connects between a first AC circuit and a second AC circuit, with switching on the thyristor AC switch to supply an AC current; a first switch; a first capacitor serially connected with the first switch, with the first switch and the first capacitor parallel-connected with the first AC circuit; a second switch; and a second capacitor serially connected with the second switch, with the second switch and the second capacitor parallel-connected with the second AC circuit; wherein when the thyristor AC switch cuts off, the first switch is operated, according to a first direction of the AC current, to conduct the first capacitor which is charged by the AC current such that a current of the thyristor AC switch is rapidly lowered for approaching a zero value, thereby rapidly cutting off the thyristor AC switch; or, wherein when the thyristor AC switch cuts off, the second switch is operated, according to a second direction of the AC current, to conduct the second capacitor which is charged by the AC current such that the current of the thyristor AC switch is rapidly lowered for approaching a zero value, thereby rapidly cutting off the thyristor AC switch.