Analysis on Characteristic Emission Spectrum of SF6 under 50 Hz AC Corona Discharge

Researches on air discharge show that the emission spectra are closely related to the type and degree of discharges, which are formed when particles transition from a high energy state to a low energy state by electrical or thermal excitation. It can provide criteria for discharge faults identification and diagnosis. However, there are few studies on the characteristic emission spectrum of $\mathbf{SF_{6}}$ discharge. In this paper, we firstly carried out a series of 50 Hz AC corona discharge experiments. Herein, the applied voltage was from 14.5 kV to 26.5 kV at 2 kV intervals, and the spectrometer was used to measure the emission spectra from 200 nm to 1037 nm. Then, the characteristic emission spectra were analyzed and compared. The relationship between the discharge degree and spectral intensity was discussed. The photon number of the characteristic spectrum bands was integrated to evaluate the emission spectral intensity. The results show that the intensity of the 308.869 nm line emission spectrum is closely related to the content of trace water, and the intensity of the 420–510 nm band spectrum from $\mathbf{SF}_{6}$ molecules and $\boldsymbol{\text{SF}_{6-\mathrm{x}}(\mathrm{x}\leq 6)}$ molecules is mainly affected by the applied voltage and discharge degree.