In the detection of partial discharge (PD) in gas-insulated equipment

the traditional fiber optic sensing system with a single-ended output configuration suffers from severe attenuation of signal intensity as the transmission distance increases

along with insufficient sensitivity. This paper investigates the influence of the relative position between the photosensitive point and the PD source on the signal intensity in a single-ended output fiber optic sensing system. On this basis

a design scheme for a dual-ended optical coupling fiber optic sensing system is proposed

where the sensing performance is optimized by introducing an additional signal increment term. Furthermore

a comparative analysis of the signal intensity characteristics of the two systems is conducted. Experimental results show that

compared with the single-ended output sensing system

the dual-end optical coupling sensing system exhibits significant advantages in signal intensity due to the introduction of the additional signal increment term. Specifically

for a 20 cm fluorescent optical fiber

the number of detectable PD pulses is increased by approximately 26.57%

the average discharge amplitude by about 27.55%

and the maximum discharge amplitude by roughly 21.63%. For an optical fiber with a length of 3 m

the above-mentioned indicators are increased by approximately 735%

118.4%

and 311.1% respectively. In addition

the dual-end transmission system also demonstrates good potential for PD source localization

with the error between the test data and the reference value not exceeding 3%. The research results of this paper provide a reference for optimizing the PD optical fiber detection sensitivity of gas-insulated equipment.