Abstract

Abstract Fiber optic ultrasonic sensors, which are highly resistant to electromagnetic interference, are expected to be implanted inside electrical equipment to achieve high-sensitivity partial discharge detection. However, the influence of the fiber optic rings on partial discharge parameters remains unclear. In this paper, a three-dimensional finite element model of the needle plate discharge is established. The effect of the fiber ring on the ultrasonic characteristics of partial discharge is systematically investigated. A parametric analysis is used to investigate the effect of the fiber ring's diameter and height on the ultrasonic characteristics. The effect of fiber optic rings on partial discharge characteristics is investigated through partial discharge tests. The results indicate a time delay in the propagation of acoustic signals compared to electrical signals, typically at the microsecond level. As the diameter of the fiber ring increases, the maximum vibration velocity at the P-point initially increases and then tends to stabilize, but it always remains lower than the value observed without the fiber ring. Additionally, increasing the height of the fiber ring results in a decrease in the maximum vibration velocity at the P-point. The presence of the fiber ring does not affect the partial discharge inception voltage, but it does influence the the apparent discharge-phase spectra. This paper provides a theoretical and experimental basis for the application of fiber optic sensing technology in partial discharge monitoring.