Distributed Online Monitoring Method for Arc Faults in MV Switchgear Based on Fluorescent Optical Fibers

Arc fault monitoring in switchgear is essential for the safety of power systems, yet it presents substantial challenges. This article presented a distributed arc fault monitoring method for medium-voltage (MV) switchgear using fluorescent optical fibers. The system overcomes the challenges of long-distance sensing with fluorescent optical fibers. Arc spectra for various fault types in switchgear were measured. The results indicated that arc spectra predominantly range from 300 to 530 nm. This provides a reliable spectral basis for monitoring. The attenuation characteristics of fluorescent optical fibers were investigated. Based on the arc spectra and fiber attenuation properties, a double-clad fluorescent optical fiber, featuring a polystyrene (PS) core and Polymethyl Methacrylate (PMMA) cladding, was selected. Its absorption spectrum ranges from 300 to 400 nm, while its emission spectrum ranges from 370 to 550 nm, with an attenuation coefficient of 0.46 dB/m. This fiber enhances optical coupling efficiency and reduces light signal transmission losses. A silicon photomultiplier (SiPM) was employed for photoelectric conversion. The SiPM was encapsulated to reduce noise in a visible light environment to 6.97% of its original value. The experimental results demonstrated that the sensor can simultaneously monitor the busbar and cable compartments of ten side-by-side switchgear, with a sensing range of 40 m.