Decomposition Characteristics of SF6/N2 Under Partial Discharge of Different Degrees

SF
₆
/N
₂
gas mixture can not only reduce the consumption of SF
₆
in power system, but also effectively alleviate SF
₆
greenhouse effect. Since SF
₆
/N
₂
can decompose under the alternating current partial discharge(PD), its decomposition characteristics are closely related to PD attributes. Therefore, the fault diagnosis method can be established through its PD decomposition characteristics. However, at present, the decomposition characteristics of SF
₆
/N
₂
mixed gas under PD have not been fully grasped, and the correlation characteristics between decomposition characteristics and PD intensity have not been obtained. To this end, this article uses pin-plate electrodes to simulate the typical metal protrusion insulation defects in GIS equipment. SF
₆
/N
₂
decomposition experiments are conducted at different PD intensity to study the correlation between the PD decomposition characteristics of SF
₆
/N
₂
mixed gas and PD intensity. The results show that: the generation rate of characteristic decomposition components such as SOF
₂
, SO
₂
, SO
₂
F
₂
, SOF
₄
, CF
₄
, CO
₂
, NO, NO
₂
, and NF
₃
are positively correlated with PD intensity; NO
₂
and (SO
₂
F
₂
+SOF
₂
+SOF
₄
+SO
₂
) can be used as the characteristic quantity to judge the whole process of PD, SO
₂
F
₂
can be used as the feature to judge the early PD, and SOF
₂
and SOF
₄
can be used as the features to judge the severe PD. The results of this article will lay the foundation for the monitoring of equipment insulation status using SF
₆
/N
₂
decomposition characteristics in the future.