Influence Mechanism of O2 on SF6Overheating Decomposition Based on Isotope Tracer

It has been recognized that the gas insulating medium SF
₆
decomposes when the partial over-thermal fault (POF) occurs inside the equipment. The insulation condition monitoring and fault diagnosis of the equipment can be carried out by utilizing the decomposition characteristics of SF
₆
under POF. Similar to the discharge decomposition of SF
₆
, trace O
₂
is an important factor affecting the decomposition of SF
₆
under POF while its mechanism is not clear yet. In order to investigate the characteristics and micro mechanism of decomposition, the paper combines isotope tracer by adding different content of
¹⁸
O
₂
as a tracer into pure SF
₆
gas and carries out experiments. The experimental results show that trace O
₂
provides O for the formation of decomposition products of SF
₆
, such as CO
₂
, SO
₂
F
₂
, SOF
₂
and SO
₂
. O
₂
promotes the decomposition of SF
₆
, but has different effects on the formation of these products with different characteristics. In combination with the characteristics, the paper further explores the microscopic mechanism of O
₂
during the decomposition of SF
₆
. The research can provide support for insulation monitoring in SF
₆
insulated equipment.