Fused Arcing Horns and Grading Rings Design, Construction, and Operating Experience on 66,000-Volt Transmission Lines of the Union Gas & Electric Company

This paper considers the use of fuses on insulator strings of high-voltage overhead conductors, to interrupt the arc at times of flashover before the line relays operate to disconnect the circuit. Consideration is first given to the original development of this idea, in which a fuse was connected between the line conductor and an arcing ring, attached to the second insulator unit. When an excessive voltage occurs on the conductor to ground, there is a flash between a two-pronged horn on the top insulator unit and the ring. The circuit is completed through the fuse, which immediately opens, breaking the arc. Further consideration is given to c later development of the principle, in which two expulsion type fuses replace the two-pronged horn at the top of the insulator string and the arcing ring is placed at the conductor end of the string. Data are presented from tests and from experience on about 100 mi. of 66,000-volt circuit, of the Union Gas and Electric Company, Cincinnati, Ohio.