Research on partial discharge detection based on distributed optical fiber acoustic sensor

Abstract

Distributed acoustic sensors (DAS) have the advantage of long-distance and distributed monitoring of vibration signals. However, there are few studies on the application of DAS for partial discharge monitoring of power equipment. There is also a lack of related theoretical and methodological studies. In this paper, the DAS-measured phase signals are theoretically analyzed from the frequency and energy perspectives, and the method of partial discharge broadband signal coverage using spectrum and energy accumulation is proposed. Fiber optic rings are employed for the detection of partial discharge signals, and the precise localization of these signals is achieved by calculating the DAS energy spectrum. The fiber optic ring is wrapped around the cable joint to achieve the detection and locating of the partial discharge signal. The results indicate that the use of a fiber optic ring can realize the sensitive detection and locating of partial discharge. The signal strength is maximum when the length of the fiber ring is equal to the spatial resolution of DAS. The sensitivity of partial discharge detection in cable joints can reach 40 pC, and the simultaneous detection and localization of partial discharge at different locations can be realized. The research can provide support for theoretical and experimental for the monitoring of partial discharge in power equipment.