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In this paper, the spatial spectral characteristics of partial discharge (PD) under different electrode models are mainly studied. In the initial corona discharge stage, the emission spectrum is mainly emitted by the N2(C3IIu→B3IIg) energy level transition of the N2 second positive band system. The spectrum is in the ultraviolet range of 294–436 nm, and its main peak is at 337 nm. The streamer discharge stage spectrum is mainly emitted by the energy level transition of the second positive band system of N2, N+, NO, and O+ and the first positive band system of N2(B3IIg→A3Σu+). In the gap of different polarity electrodes, the ultraviolet spectrum content near the positive polarity is more abundant. The UV spectra ranges are 202–225 nm and 229–292 nm, respectively. The discharge of the needle–sphere system is more intense in visible light and near-infrared light, with peaks at 500 nm and 777 nm, respectively. In addition, the PD process based on the finite element method is simulated by COMSOL Multiphysics software. The simulation results show that the distribution of high-energy electron density varies with the electrode spacing and discharge model. The influence of particle energy level transition on the spatial spectral characteristics of PD is verified. This work provides important insights and possibilities for future fluorescent fiberoptic sensing and positioning for spatial PD detection and positioning using spectral characteristic peaks as detection quantities or excitations.

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SiO2 cladding YAG:Yb crystal core fiber fabricated by the modified rod-in-tube method was demonstrated as a remote sensor for partial discharge faults (PD). The spectra of the crystal fiber and PD fault standard source were measured. When the applied voltage of the PD source is 36 kV, the detection pulse intensity of the sensor decays exponentially with the change of the distance from the PD source to the sensing probe (SSD). Its decay trend in the range of 0-25 cm conforms to the Beer-Lambert law. When the fixed SSD is 7 cm and the applied voltage range of the PD source varies from 35 to 39 kV, the pulse frequency detected by the sensor has a good linear relationship with the applied voltage (R2 = 0.99279). The experimental results indicate that the crystal optical fiber sensor can realize the remote sensing of PD monitoring.