Optical fiber vibroacoustic sensing technology has significant potential for detecting discharge defects in gas insulated switchgear (GIS). However

a lack of research into fiber sensor multiplexing techniques has hindered the widespread deployment of optical fiber vibroacoustic sensing systems. This paper proposes a distributed detection method for metal particle defects in GIS based on coherent optical time-domain reflectometry (COTDR). A fiber sensing topology is constructed

and the design of the fiber sensing units is optimized for this method. A 110 kV GIS metal particle defect detection experimental platform is also established to evaluate the distributed detection capability of the developed system. Experimental results demonstrate that the distributed optical fiber sensing system developed in this study is capable of detecting vibroacoustic signals generated by the free fall of spherical metal particles with a diameter of 2 mm from a height of 20 mm. Moreover

the system enables the localization of vibroacoustic events

allowing for the acquisition of spatial information about the defect based on the deployment positions of the sensing units. In addition

the sensing system can also detect the acoustic pulse signals generated by non-jumping metal particle defect with discharges on the insulator surface

shell and central conductor in GIS. The findings of this study provide a novel solution for the operation and maintenance of GIS equipment.