Decomposition characteristics of SF6 under different spark energies

For the purpose of utilizing decomposition component analysis (DCA) for fault diagnosis of SF
6
gas insulated equipment further, SF
6
spark decomposition experiments under different spark energies were carried out on the frequency and energy-controllable SF
6
spark decomposition test platform. The amount of gaseous by-products of SF
6
sparks were measured by GC-MS. Atomic relative content of solid products were analyzed by XPS. The main gaseous by-products of SF
6
sparks include SOF
2
, SO
2
F
2
, SOF
4
, SO
2
, as well as CF
4
, and the amount of them increases with spark number. The amount of SOF
2
increases with single spark energy and tend to be saturated, while SO
2
F
2
decreases. It depends strongly on the differences of both the energies consumed in SF
6
dissociation process into SF
5
, SF
4
, SF
2
, and hydrolysis rates of SOF
4
and SF
4
. Besides, CF
4
increases with single spark energy and tend to be saturated, and SOF
4
shows a linear dependence, but SO
2
is hardly influenced by spark energy distinctly. In solid products, relative content of F, S, Fe, W increases with spark energy. The main existence forms of Fe include FeS, FeF
3
, Fe
2
O
3
, and pure Fe, thereunto the relative content of FeS and pure Fe increases with spark energy.