SF

6

electrical equipment is widely used. There have been many SF

6

equipment failures and even accidents. Real-time monitoring of the decomposition products of SO

2

H

2

S and CO characteristic gases in SF

6

equipment can effectively monitor equipment latent discharge failures. This paper first designed an online monitoring system for SF

6

decomposition products based on TDLAS. According to the absorption characteristics of CO

H

2

S and SO

2

strong absorption peaks at 1 567 nm

1 578 nm and 1 535 nm were

selected in the near-infrared region to improve detection sensitivity. The interference test proved that SF

6

gas has no interference to the three decomposition products in the selected band

and can accurately detect the three decomposition products. The high and low temperature cycle test results show that the temperature stability of the laser is controlled within 0.1 ℃

which can ensure the stability of detection. Using background noise denoising

calibration and inversion are carried out according to the relationship between the concentration of different decomposition components and the second harmonic. The linear relationshipisgood

which meets the detection requirements of the power industry and has good practical value.