Review of the decomposition characteristics of eco‐friendly insulation gas

Abstract

As one of the major concerns of climate change, identifying a proper eco-friendly insulation gas for replacing sulphur hexafluoride (SF 6 ) becomes a prominent research topic in recent years. c-C 4 F 8 , CF 3 I, C 5 F 10 O, C 6 F 12 O and C 4 F 7 N are some potential alternatives that are proved to have excellent characteristics, including high insulation strengths and low Global Warming Potentials (GWPs). Beyond these key factors, the decomposition products of these alternatives are closely related to the gases' insulation performance, as well as the safety of operators and the compatibility with other materials. In addition, the type and content of decomposition products can be used for fault diagnosis. Therefore, a number of studies were carried out to reveal the decomposition mechanism of these alternative gases, and then to explore the gases' application feasibility and strategy. The recent advances obtained in these studies, including theoretical calculation methods, detection of gas decomposition products, decomposition mechanism are reviewed, and some perspectives for future works are proposed. It is concluded that the phenomenon of solid matter precipitation in c-C 4 F 8 and CF 3 I gas decomposition cannot be ignored and that more research is needed to reveal the influence of buffer gases, microaerobic, micro-water and other impurities on the gas decomposition process.This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Optical Characteristics and Fault Diagnosis of Partial Discharge in C4F7N/CO2 Gas Mixture and SF6 Based on Novel Multispectral Microarray Detection

“…where (1) to (8) are some of the main reactions in the C4F7N/CO2 gas mixture. Equation ( 9) to (11) are some of the main reactions in SF6 [14,17,18].…”

“…However, the current research on C4F7N/CO2 gas mixture equipment is mostly about its electrical insulation performance, decomposition characteristics and physical state [8][9][10]. There are very few studies on PD detection in C4F7N/CO2 gas mixture, especially optical detection [11].…”

Influence of micro‐water on AC breakdown characteristics of C 4 F 7 N/CO 2 gas mixture under non‐uniform electric field

“…SF 6 is an ideal insulation and arc extinguishing gas medium, which has been widely used in gas insulated switchgear (GIS), gas insulated transmission line (GIL), current transformer (CT) and other gas insulated electrical equipment [1]. However, its global warming potential (GWP) is 23,500 times of CO 2 , and its impact on the environment cannot be ignored [2][3][4]. The Paris Agreement pointed out the goal of net zero emission of greenhouse gases should be realised by the second half of this century, therefore, it is urgent to take measures of finding eco-friendly alternative gas insulation medium [5,6].…”

Arc decomposition behavior of C 4 F 7 N/Air gas mixture and biosafety evaluation of its by‐products

“…Besides, the dielectric strength of pure C 4 F 7 N gas is twice that of SF 6 and the insulation performance of C 4 F 7 N/CO 2 with 18%-20% C 4 F 7 N is equivalent to that of SF 6 [9]. Comprehensive performance evaluations of C 4 F 7 N on insulation performance [6][7][8][9], decomposition characteristics [10,11] and material compatibility [12] have been conducted, and have demonstrated that C 4 F 7 N has the application potential for both medium-voltage and high-voltage GIE. For example, General Electric successfully developed a 245 kV current transformer and 145 kV gas-insulated switchgear with C 4 F 7 N gas as the insulation medium and put them into trial operation [13].…”