Due to its excellent insulation performance and lower greenhouse effect

C

4

F

7

N is considered as an excellent alternative to SF

6

for environmental protection insulation gas. C

4

F

7

N/CO

2

hybrid gas insulation equipment has been gradually promoted and used. Since the insulation performance of the gas mixture is related to the content of C

4

F

7

N

the insulation state of C

4

F

7

N/CO

2

gas mixture electrical equipment can be effectively evaluated through the detection of trace C

4

F

7

N in the gas mixture. In this paper

the infrared spectral information of C

4

F

7

N was determined through the infrared spectral platform. Through the detection of C

4

F

7

N/CO

2

gas mixture at 100-2 000 μL/L C

4

F

7

N concentration

the optimal detection band of trace C

4

F

7

N was determined. A micro-C

4

F

7

N detection platform based on NDIR technology was built. The measurement channel filter was 7.9 μm

and the detection of 12.6-52.5 μL/L C

4

F

7

N was realized. The linear fitting coefficient

R

2

between C

4

F

7

N gas concentration and inversion signal value was 0.989

and the maximum absolute error was 0.107. The research results provide a feasible scheme for the insulation state evaluation of C

4

F

7

N/CO

2

gas mixture insulation equipment.