Detection of Constituents From SF_6 Decomposition Under Partial Discharge and Recognition of Insulation Defect Coding

Abstract

To recognize the insulation defects inside the totally enclosed gas insulated switchgear(GIS) by the contents of the constituents from decomposed SF6 gas,it is necessary to establish an association rule between the decomposed gas composition and insulation defects beforehand.Utilizing the established platform for the partial discharge-caused decomposition experiments of SF6 gas,a lot of partial discharge experiments for four kinds of typical insulation defects were performed,and it was found that under the partial discharge caused by different insulation defects there were obvious differences among the decomposition characteristics of SF6 gas corresponding to these defects,and the component contents as well as their variation rates follow special law,for this reason a thinking and corresponding approach to recognize insulation defects by coding tree of gas composition contents were proposed.The ratio ranges of three groups of gas composition contents,i.e.,SOF2/SO2F2,CF4/CO2 and(SOF2+SO2F2)/(CO2+CF4),are coded,then corresponding ratio coding tree was established and the coding combination to recognize four kinds of insulation defects was attained.For the condition that the composition content coding fell into a cross area,an auxiliary method to finally confirm the basis of coding was given.