3D Printing TechniqueImproved PhaseSensitive OTDR for Breakdown Discharge Detection of GasInsulated Switchgear In this paper, we propose and demonstrate a gasinsulated switchgear (GIS) breakdown discharge detection system based on improved phasesensitive optical time domain reflectometry (xcfx86OTDR) assisted by 3Dprinted sensing elements. The sensing element is manufactured by a material with a high Poisson ratio for enhancement of the sensitivity of xcfx86OTDR to the acoustic emission detection during the breakdown discharge process. In our experiment, seven 3Dprinted sensing elements incorporating with optical fibers are attached tightly onto the shell of the GIS, which are monitored by xcfx86OTDR to localize and detect the acoustic emission signal resulted from the breakdown discharge. Ultimately, thanks to the phase demodulation, acoustic signals induced by the breakdown discharge process can be captured and recovered. Furthermore, the time delay analysis of detected signals acquired by different sensing elements on the GIS breakdown discharge unit is able to distinguish the location of the insulation failure part in the GIS unit. It suggests that the xcfx86OTDR incorporated with 3D printing technology shows the advantage of robustness in GIS breakdown discharge monitoring and detection.

A SiPMBased Trinal Spectral Sensor Developed for Detecting Hazardous Discharges in HighVoltage Switchgear Electric discharges seriously threat the safety of highvoltage switchgear. In this paper, a spectrumbased optical method is proposed for hazardous discharge monitoring. A SiPMbased trinal spectral sensor is developed with good performances in terms of sensitivity, defect resolution, and risk evaluation. Experiments carried out on two types of artificial discharges (i.e., partial discharge and arc discharge) demonstrate that the light intensities coupled in the three spectral bands account for different proportions and the ratio among the three components generally experiences a regular change with increase in severity of discharge. The typical spectral ratio values are then acquired for hazard rating of discharge and recognition of discharge types with high confidence.