Deeply mining the electrothermal corrosion information of the decomposition products of SF

6

improves the accuracy of latent fault diagno

sis of GIS equipment. Studying thermal decomposition reaction of the SF

6

-epoxy system and clarifying the corresponding relationship between carbon-based characteristic decomposition products and degradation of insulating materials can solve the contradiction between the singularity of the characteristic components and the diversity of their source. In this paper

the thermal decomposition process of SF

6

-epoxy is systematically measured by synchronous thermogravimetry (TG)/differential scanning calorimetry (DSC)

which characterizes the temperature range and heat release of three distinct pyrolysis stages. Nine decomposition products of carbon

sulfur and oxygen are identified by the online gas chromatography. According to the panoramic pyrolysis reaction mechanism of the SF

6

-epoxy system

CO

2

is proposed as the characteristic decomposition component to judge the thermal corrosion deterioration of epoxy resin at high temperature (

>

500 ℃). CH

4

directly responds to the thermal degradation of epoxy insulating materials at 300-500 ℃. SOF

2

H

2

S and H

2

comprehensively determine the ultra-low water concentration of SF

6

-epoxy system.