Partial discharge occurs with acoustic

electrical

optical

and thermal phenomena. As the basis of the research on the optical detection of partial discharge（PD）

the propagation characteristics of the PD signal in GIL must be paid attention. This paper simulates the propagation of PD optical signals in GIL by modeling GIL with different structures and specification parameters. The influence of specification parameter difference caused by voltage level on the optical signal propagation of GIL partial discharge is studied by observing the optical parameters of the probe surface and the detection point when the position of the PD source is different. The results show that the structure of the GIL cavity will affect the spot distribution and the relative irradiance value on the detection surface; the location of the partial discharge source has a significant effect on the spot distribution on the detection surface

but has little effect on the relative irradiance value; the larger the voltage level

the more distinct the spot distribution on the detection surface and the smaller the average relative irradiance value. The research results can provide reference for the manufacture of GIL equipment and the research of partial discharge optical detection.