Vibration-based Diagnosis of Core Fractures in Composite Insulators

The most serious condition of a non-ceramic insulator is when the core is damaged, increasing the possibility of a catastrophic failure resulting in the conductor being released. This condition is unacceptable, as it may lead to safety issues both for the public and workers. Furthermore, core damage may occur without any detectable sign on the surface of the insulator. This paper presents a method aiming at the detection of core damages by testing the insulator based on mechanical excitation and measurement of the resulting vibration in the ultrasonic range. The testing arrangement and results on new and damaged insulators are presented in this paper.