Influence of trace H(2)O and O(2) on SF(6) decomposition products under arcing conditions in electric power equipment

• Main Authors: Ren Yang, Mengyuan Xu, Chen Guan, Jing Yan, Yingsan Geng
• Format: Article
• Language: English
• Published: Wiley 2019-04-01
• Series: The Journal of Engineering
• Subjects: electrochemical sensors; arcs (electric); condition monitoring; decomposition; chromatography; circuit breakers; fault diagnosis; oxygen; sulphur compounds; carbon compounds; arcing energy; arcing conditions; electric power equipment; arc extinguishing medium; gas decomposition products; decomposition tests; circuit breaker; insulating medium; gas chromatograph; electrochemical sensor; formation process; decomposition characteristic component; voltage 40.5 kV; H(2)O; O(2); SF(6); SOF(2); SO(2); CO; CO(2); CF(4); C(2)F(6); C(3)F(8)
• Online Access: https://digital-library.theiet.org/content/journals/10.1049/joe.2018.8832

SF(6) has been widely used as an insulating and arc extinguishing medium in electric power equipments. Detection of gas decomposition products is an important means for condition monitoring and fault diagnosis. Trace H(2)O and O(2) have a significant influence on the species and concentrations of SF(6) decomposition products. It is important to explore the influence mechanism of trace H(2)O and O(2) on SF(6) decomposition products under arcing conditions. A series of SF(6) decomposition tests were carried out on a 40.5kV SF(6) circuit breaker, and a gas chromatograph and an electrochemical sensor were used to measure decomposed components. First, the H(2)O content remained constant, and the O(2) content and arcing energy changed in the tests. It has been found that the decomposition products of SF(6) are SOF(2), SO(2), CO, CO(2), CF(4), C(2)F(6) and C(3)F(8). Then, the O(2) content remained constant, and the H(2)O content changed. The decomposition products are mainly SOF(2), SO(2), CO and CO(2). Concentrations of all these decomposition products increase first and then tend to be stable slowly over time, but change differently with the increase of H(2)O and O(2) contents, because H(2)O and O(2) play different roles in the formation process of each decomposition characteristic components.