Sulphur hexafluoride gas decomposition products of fixed metallic defect in coaxial gas insulated switchgear

A reliable diagnostic technique of Gas insulated switchgear condition monitoring is used in this research for the detection of Sulphur hexafluoride gas (SF6) decomposition products due to its high sensitivity and anti-electromagnetic interference; it is known as decomposition by-product method. A simulated coaxial decomposition chamber was designed and used to simulate the decomposition of SF6 under the effect of fixed metallic artificial defect on the surface of the spacer at the pressure of 0.2MPa when the chamber is energized at a 45KV experimental voltage over the period of 30 hours due to the presence of partial discharge caused by the artificial defect. The decomposition products (HF, SOF
₂
, SOF
₄
, SO
₂
F
₂
, SO
₂
F
₁₀
, SiF
₄
, SO
₂
, CO, C
₂
F
₆
and CF
₄
) were detected offline by FTIR spectrometer. These decomposed products and its concentration can be used detect and identify the type and the level of fault in switchgear (contamination fault) before failure for purpose of preventive maintenance.