Research on decomposition characteristics of SF6 under partial discharge at different gas pressures

In order to obtain the decomposition characteristics of SF₆ under partial discharge (PD) at different gas pressures, an experiment platform was established and PD decomposition experiments of SF₆ at different gas pressures was carried out in 96 hours. In the experiments, gas chromatography and gas chromatography-mass spectrometry were adopted to quantitatively determine the characteristic components of decomposition. The variation of these characteristic components at different gas pressure and the role of gas pressure in this process was analyzed on the basis of experiment results. It is concluded that, the generation rate of some characteristic components (such as CO₂, SO₂, SOF₂) significantly declines with the increasing pressure. Among them SOF₂ has the most significant change, while the generation rate of SO₂F₂ only reduces slightly. This troubles the diagnoses based on the signal characteristic ratio c(SOF₂+SO₂)/c(SO₂F₂). Therefore, To use a new characteristic ratio, c(SO₂F₂+SOF₂+SO₂)/c(CO₂) was proposed which is not obviously affected by pressure.