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

Abstract

The use of $SF_{6} / {N}_{2}$ mixed gas is a technical means to effectively alleviate the greenhouse effect and lower the liquefaction temperature, which has been applied in GIS(Gas Insulated Switchgear). During the long-term running of $SF_{6} / {N}_{2}$ GIS, some insulation defects will occur and deteriorate, and the characteristic decomposition components of $SF_{6} / {N}_{2}$ gaseous mixture under PD (Partial Discharge) can be used to accurately identify whether there are serious insulation defects in GIS. Therefore, this paper focuses on the relationship between $SF_{6} / {N}_{2}$ decomposition and PD. Firstly, an experimental platform for $SF_{6} / {N}_{2}$ mixed gas PD was built, and then PD decomposition characteristic test under the condition of needle plate defect was carried out. Finally, the correlation characteristic between the content of the generated characteristic decomposition component and the discharge quantity was analyzed. The main conclusions can be summarized as follows: the production of $SOF_{2}, SO_{2} {F}_{2}, {NO}_{2}$, and NF 3 have a positive relation with PD intensity; The content and change rule of NO 2 can be used to identify the overall process of PD, ${SO}_{2} {F}_{2}$ can be used to determine early PD, SOF 2 can be used to determine severe PD. The research results of this paper will lay the root for the fault diagnose of $SF_{6} / {N}_{2}$ gas insulation equipment by $SF_{6} / {N}_{2}$decomposition characteristics in the future.