SF₆ Byproducts in High-Humidity Environment: an Experimental Evaluation between 200^oC and 500^oC

Abstract

Abstract: In the occurrence of arc discharges, spark discharges, corona discharges and overheated faults in electrical equipment, SF ₆would be decomposed to complicated byproducts, such as SO₂ , H₂S and HF. Analyzing these byproducts is an effective method to judge the internal operation condition of electric equipment. In order to study characters of SF₆byproducts at different temperature of overheated faults in the electric equipment, a series of overheated faults of electric equipment were simulated. SF₆is very stable and not significantly decomposed at 200^oC, 250^oC and 300^oC. SF₆is significantly decomposed to SO₂, H₂S and HF at 350^oC. The concentration of SO₂, H₂S and HF was 7.2, 1.6 and 1.9 μL/L after heating for 5 hours in environment of SF₆with 3616 μL/L water, and it was increased to 23.0, 3.0 and 1.2 μL/L 3 hours later. SF₆is more easily to be decomposed and decomposed more rapidly at higher temperature. The concentration of SO₂, H₂S and HF was 62.2, 15.6 and 3.6 μL/L after heating for 5 hours in environment of SF₆with 4064 μL/L water, and it was increased to 91.4, 25.2 and 2.3 μL/L 3 hours later. SF₆will be decomposed to format HF, which is strongly corrosive and whose concentration is likely to decrease when it is above a certain concentration.