INSULATOR PROTECTIVE DEVICE

摘要

PROBLEM TO BE SOLVED: To surely arrest a creeping streamer with a discharge electrode and cut off a dynamic current arc when an insulator body is used in a damaged area from sea wind by forming the discharge electrode into a ring shape kept near to or in contact with the side periphery of the insulator body. SOLUTION: A discharge electrode 40 is formed into a ring shape kept near to or in contact with the side periphery of an insulator body 2, and the gap D between the insulator body 2 and the discharge electrode 40 is set to the size that a creeping streamer of the insulator body 2 can be arrested by the discharge electrode 40. An insulating cover 21 storing a current limiting element 36 is fitted to the head section of the insulator body 2 to set a protective device. When an abnormal voltage such as a lightning surge is propagated to an insulated electric wire 4, the abnormal voltage is discharged through the path of electric wire 4→cap metal fittings 6→current limiting element 36→electrode 10→discharge gap G→base metal fittings 12→ground. The commercial- frequency dynamic current is interrupted by the current limiting element 36 existing in the discharge path, the occurrence of a dynamic current arc is blocked, and the biased heat breakdown of the insulator body 2 and the open circuit accident of the electric wire 4 caused by the arc can be prevented.