Study on the Compatibility of Typical Materials in GIT with C4F7N/CO2 Gas Mixture

To explore the compatibility of C
4
F
7
N/CO
2
gas mixture and typical materials used in gas insulated transformer (GIT), thermal accelerated aging test was carried out and the gas mixture after test was analyzed by gas chromatography-mass spectrometry (GC-MS) to estimate the interaction intensity between the reactants. The results showed that most of selected materials have good compatibility with C
4
F
7
N/CO
2
gas mixture except for polyester cushion block and bakelite nut which caused C
4
F
7
N decomposed into C
3
F
6
and C
3
F
8
, indicating poor compatibility between the gas mixture and polyester cushion block and bakelite nut.