Detection of decomposition products of SF6/air gas mixture by electron attachment mass spectrometry

Abstract

Sulphur hexafluoride (SF 6 ) is widely used in gas insulation, and its decomposition products can be used to diagnose potential insulation failures. Quick and accurate detection of decomposition products can help to understand equipment-operating conditions in time. In this study, the decomposition products of SF 6 /air gas mixtures under different pulsed discharge voltages were studied. It was found that the main products were SOF 2 , SO 2 F 2 , SO 2 , CF 4 and SOF 4 , and the yields of SOF 2 , SO 2 F 2 , SO 2 and SOF 4 increased with the number of discharge pulse. The productive rate of SOF 2 , SO 2 and SOF 4 were positively correlated with the discharge voltage, and when the discharge voltage increased from 5 to 15 kV, their yields after 50,000 discharges increased by 49%, 120% and 1100%, respectively. The productive rate of SOF 2 and SO 2 were positively correlated with the proportion of air in the gas mixtures while that of SOF 4 was opposite. When the proportion of air increases from 0% to 90%, their yields after 50,000 discharges became 270%, 3169% and 10% of the originals, respectively. In addition, the productive rate of SO 2 F 2 was not affected by discharge voltage and the proportion of air in the gas mixtures. SO 2 F 2 , SOF 2 , SOF 4 and SO 2 can be used as the basis for judging the discharge failures and the discharge degree of power equipment.This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.

The Uncertainty Evaluation of Determining the Trace H2S in SF6/N2 Insulating Gas Mixture by Cavity Ring-Down Spectroscopy

“…SF6 is currently the most excellent gas insulation medium and arc extinguishing medium [1][2][3] and has been widely used in fields such as power, petroleum, aerospace, etc. However, SF6 is a strong greenhouse gas with a Global Warming Potential (GWP) 23900 times that of CO2, and has a lifespan of up to 3200 years in the atmosphere.…”

“…There may be partial discharge or overheating faults caused by insulation defects in SF6 gas insulated equipment, leading to SF6 decomposition. Under the action of impurities such as trace oxygen and water, characteristic gases such as SO2, HF, H2S, CO, CF4, SOF2, SO2F2, and SOF4 are generated [3] . Detecting the content and trend of SF6 decomposition products to determine the cause and discharge amount of partial discharge is a hot research topic both domestically and internationally.…”

“…H2S is one of the characteristic products of SF6 and a hallmark of high-energy partial discharge [3] . Laser cavity ring-down spectroscopy (CRDS) for gas component detection has good selectivity and high accuracy (1 μL/L), fast response time (<5 s), and can achieve online monitoring [10][11] .…”

Analysis of SF6 decomposed products by fibre‐enhanced Raman spectroscopy for gas‐insulated switchgear diagnosis

“…Due to the diversity of complex compositions and extremely low concentrations (10 −9 -10 −6 ) of SF 6 decomposed products, the measurement instruments require high selectivity and sensitivity. Gas chromatography (GC) [6,7] coupled with pulsed discharge helium ionisation discharge detector (PDHID) or mass spectrometry (MS) is the current state of the art for SF 6 decomposition analysis with ppb-level sensitivity, high selectivity, and quantification accuracy. However, GC has several drawbacks for time-resolved and on-site applications: it requires different chromatography columns for the separation of sulfides and carbides, is time-consuming, expensive, difficult to calibrate, and limited in miniaturisation.…”

Adsorption properties of Ni cluster modified TiO 2 (1 0 1) towards SF 6 decomposition gases

“…During the long-term stable operation of GIS, its insulation performance will be reduced to a certain extent, and the possibility of local flashover discharge in GIS will be greatly increased, which will lead to the decomposition of the stable SF 6 gas to produce some low fluorine sulfides (SF x , x = 1-5) [7,8]. These low fluorine sulfides will react with trace H 2 O molecules and O 2 molecules existing in GIS to produce a series of characteristic decomposition products of SF 6 , such as SO 2 , SOF 2 , and SO 2 F 2 [9][10][11][12]. The insulation strength of these characteristic decomposition products is far lower than that of SF 6 gas, which further reduces the insulation effect and aggravates electrical discharge in GIS equipment [13][14][15][16].…”