Decomposition Characteristics of SF6 and Component Features Extraction Under Negative DC Partial Discharge

Abstract

To obtain the decomposition characteristics of SF6 under different types of negative DC partial discharge, and then establish a fault diagnosis method based on decomposition component analysis, the author extracts four typical defects that may appear in SF6 gas-insulated electrical equipment, and obtains the decomposition characteristics caused by the four kinds of defects under negative DC. The differences of SF6 characteristic decomposition component concentration and concentration ratio in the four cases are analysed, and the results show that the SF6 gas will decompose under the negative DC-PD caused by the four defects and generate five stable decomposed components that are CF4, CO2, SO2F2, SOF2, and SO2. The concentration and concentration ratio of five gas both change with its specific regulation. Spectral Clustering algorithm is used to identify and diagnose the two feature quantities, which shows that the two types of characteristic parameters can effectively reflect the PD type, and the concentration ratio performs better.