Gas decomposition and electrode degradation characteristics of a 20% C 3 F 7 CN and 80% CO 2 gas mixture for high voltage accelerators

High voltage

article

Ibrahim Iddrissu¹  Qinghua Han¹  Lujia Chen¹  Louis Maksoud²  Yannick Kieffel² 

[1] Department of Electrical and Electronic Engineering, The University of Manchester;Materials Research Department

关键词: ageing;    carbon compounds;    chromatography;    dissociation;    electric breakdown;    electrochemical electrodes;    gas mixtures;    mass spectroscopy;    organic compounds;    X-ray diffraction;    X-ray photoelectron spectra;   

DOI  :  10.1049/hve2.12120

学科分类：物理（综合）

来源: Wiley

【 摘 要 】

Sulphur hexafluoride (SF 6 ) is a potent greenhouse gas used in high voltage accelerators. As a promising alternative to SF 6 , the C 3 F 7 CN/CO 2 gas mixture and its by-products are of great interest to ensure the safe operation of accelerators that will adopt any SF 6 -free solution. This work experimentally examines the electrical ageing characteristics of a 20% C 3 F 7 CN/80% CO 2 gas mixture tested using spark gaps under a pressure of 7.2 bar (abs.). Gas samples were collected after 1000 DC breakdowns and analysed using gas chromatography mass spectrometry (GC-MS) with an estimated toxicity value of 54,459 ppm v , which indicates the aged mixture to be non-toxic. Subsequent investigation was conducted on the gas-solid interface after 500 breakdowns for both SF 6 and the 20% C 3 F 7 CN/80% CO 2 gas mixture. Aged electrodes were analysed using X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) techniques. Electrode surface analysis revealed the formation of metal fluorides on the electrode surface tested using the 20% C 3 F 7 CN/80% CO 2 mixture, whereas metal fluorides and sulphides were detected for electrodes tested with SF 6 . The findings provide a reference on the toxicity and gas-solid interaction of the electrically aged 20% C 3 F 7 CN/80% CO 2 gas mixture for potential retro-fill application in high voltage accelerators.

【 授权许可】

CC BY|CC BY-ND|CC BY-NC|CC BY-NC-ND