An Innovative Fluorescent Fiber Sensor Based on Ce/Tb Co-Doped Silica Fiber for Partial Discharge Detection

A novel fluorescent fiber sensor based on cerium (Ce) and terbium (Tb) co-doped silica fiber (CTDSF) for partial discharge (PD) detection is proposed. The luminescence mechanism and the PD detection principle of CTDSF are theoretically investigated. The CTDSF is fabricated using the rod-in-tube (RIT) technique combined with the CO2 laser-heated drawing method. The intense emission peak of Tb
$^{{3}+}$
ions located at 542 nm (
$^{{5}}\text{D}_{{4}}$
-
$^{{7}}\text{F}_{{5}}$
transition) is excited at 302 nm, which indicates the energy transfer (ET) between Ce
$^{{3}+}$
and Tb
$^{{3}+}$
ions. Moreover, the excitation peak region near 302 nm is well aligned with the PD light emission spectrum. Subsequently, the PD time-domain signals of the needle-plate defect are experimentally measured by utilizing the CTDSF sensor, high-frequency current transformer (HFCT), and plastic scintillation fiber (PSF). Also, the experimental results demonstrate that the CTDSF sensor can detect PD signals and has an excellent PD detection linear response with a sensitivity of 0.22 ns
$\cdot \text{V}$
/pC. Furthermore, the sensitivity of the CTDSF sensor is approximately 2.4 times dramatically higher than that of the PSF sensor. The CTDSF sensor integrated with the all-fiber system is predicted to have a wide range of potential applications for online PD detection.