PURPOSE: To provide a semiconductor type arrestor which has a large discharge withstand current rating and can remarkably shorten the voltage dropping time as compared with the conventional example and in which element breakdown hardly occurs even when the device is subjected to dynamic currents.
CONSTITUTION: Such a thyristor as a GTO thyristor 1 which can make self- extinction of arc is used as the thyristor element interposed between a power system and the ground. In addition, by providing a turning-off circuit 7 which allows the thyristor 1 to perform extinction of arc a prescribed period after the ignition of the thyristor 1, the thyristor 1 is caused to make the extinction of arc without waiting for the electric current to become zero. When a current- limiting element is connected in series with the element 1, moreover, a dynamic current can be surely interrupted.
ISHIBASHI CHIHIRO
ICHIOKA TATSUMI
TANGE MASAJI
NGK INSULATORS LTD