Dry Air Decomposition Component Detection and Defect Identification

The environmentally friendly switchgear that employs dry air as an insulating medium has extensive application prospects. Monitoring the decomposition components of partial discharge in dry air is of paramount significance for assessing defects in this type of switchgear. This study utilizes Gaussian simulation software to analyze potential pathways for partial discharge decomposition in dry air, calculating the reaction heat for various chemical reaction pathways. The proposal is to employ the decomposition gases CO
2
, CO, and NO
2
as characteristic components to reflect the types of defects in dry air-insulated switchgear. Various experimental platforms were established to study the distribution patterns of decomposition components of dry air under different discharge voltages and times for different defect types, including metal protrusions, insulator gap defects, and insulator metal contamination defects. The research indicates that with increasing discharge time and voltage, the concentrations of decomposition gases CO
2
, CO, and NO
2
linearly increase, with NO
2
gas concentration reaching saturation first. The selection of c(CO
2
+CO)/c(NO
2
) and c(CO
2)/
c(CO) as characteristic quantities is proposed to discriminate the types of partial discharge defects in dry air-insulated switchgear. This serves as a reference basis for the monitoring and diagnosis of defect types in dry air-insulated switchgear.