Non-contact surface wave sensing of wire fault precursors

A non-contact surface wave method of aging related insulation damage (fault precursors) detection in cables is proposed. Aging related hot spot detection is examined to demonstrate the efficacy of this method on an unshielded cable. A non-contact surface wave launcher launches a Gaussian chirp signal (120 MHz center frequency and 100 MHz bandwidth) onto the surface of a 22.9 ft. long power cable. The propagating wave is reflected from the location of the aging hot spot as well as from the open end. The time frequency cross-correlation clearly identifies the location of the aging hot spot.