Emission Spectrum Analysis of SF6 under Spark Discharge and Surface Discharge

This paper carried out experiment to simulate spark discharge and surface discharge defects commonly occurred in sulfur hexafluoride (SF6) gas insulated electrical equipment, and detected the emission spectra of 200–1037 nm by a spectrometer. Based on the mechanism of partial discharge and SF6 decomposition, the spectra and the related formation are analyzed. It is shown that the emission spectra under spark discharge and surface discharge are mainly generated by fluorine atoms and ions, and the spectra span the whole wavelength of 200–1037 nm. Different from the spark discharge, the spectra generated by the radiation of copper atoms and ions are observed in surface discharge due to the introduction of copper material. The electron temperatures of spark discharge and surface discharge are calculated and compared according to the multi-spectral slope method. The results indicate that the electron temperature of surface discharge is higher than that of spark discharge, which explains the higher average spectral intensity of 200–650 nm under surface discharge. This paper can provide a reference for the monitoring of SF6 insulated electrical equipment.