Inhibition Effect of Solid Products and DC Breakdown Characteristics of the HFO1234Ze(E)-N2-O2 Ternary Gas Mixture.

Heng Liu,A Manu Haddad,Qingmin Li,Jingrui Wang,Yuheng Jiang

doi:10.1021/acsomega.1c03020

Abstract

HFO1234ze(E) is an environmentally friendly SF6 substitute gas with prominent application potential. To suppress the generation of the HFO1234ze(E) solid decomposition products, which may cause great hazards to the gas–solid insulation strength, a gas mixing scheme screening method based on the reactive force field (ReaxFF) molecular dynamics (MD) simulation was innovatively proposed. The simulation results show that the inhibitory effect of O2 on the formation of HFO1234ze(E) solid products is better than those of CO2 and CF4. Further study shows that when O2 accounts for 3.33% of the gas mixture, the solid precipitate content is reduced by 48%. The experimental study shows that an O2 content of 3.33% can inhibit the generation of solid products by more than 50%. Besides, compared with HFO1234ze(E)-N2, the DC breakdown voltage of HFO1234ze(E)-N2-O2 is slightly increased, and the breakdown voltage dispersion degree and continuous breakdown voltage drop rate are decreased. This work gives a feasible solution for the suppression of HFO1234ze(E) solid decomposition products and provides an efficient method for solving similar problems of environmentally friendly insulating gas in C/F/O/N systems.

Highlights

Due to its high dielectric strength and excellent arc extinction performance, sulfur hexafluoride (SF6) has been widely used in power transmission and distribution equipment, such as gasinsulated switchgear (GIS) and gas-insulated transmission line (GIL).[1,2] the global warming potential (GWP) of SF6 is 23 900 times that of CO2 and its atmospheric lifetime is as long as 3200 years.[3]
To achieve this research goal, we innovatively proposed a research method for evaluating the inhibition effect of the HFO solid decomposition products by buffer gases based on ReaxFF molecular dynamics (MD) simulation, which greatly improved the efficiency of the buffer gas screening process
Simulations and experiments are performed to study the inhibitory effect of the buffer gas on the HFO solid decomposition products

Summary

Introduction

Due to its high dielectric strength and excellent arc extinction performance, sulfur hexafluoride (SF6) has been widely used in power transmission and distribution equipment, such as gasinsulated switchgear (GIS) and gas-insulated transmission line (GIL).[1,2] the global warming potential (GWP) of SF6 is 23 900 times that of CO2 and its atmospheric lifetime is as long as 3200 years.[3]. Researchers have made some progress in searching for potential SF6 substitute gases Some alternative candidates such as c-C4F8,6 CF3I,7 C5F10O, and C4F7N8 were identified because of their strong insulation properties (equivalent to or stronger than SF6). The shortcomings of the aforementioned candidate gases in terms of the greenhouse effect (c-C4F8), material compatibility (CF3I), and toxicity (C5F10O and C4F7N) limit their wide application to some extent. HFO1234Ze(E) (referred to as hydrofluoroolefins (HFO) when it does not cause ambiguity), one of the hydrofluoroolefins family gases, shows favorable properties in replacing SF6 in medium voltage systems.[9,10] The GWP of this gas is very low (GWP = 6) and its ozone depletion potential is zero.[10] The experimental results indicate that the breakdown voltage of HFO is 74−94% of SF6 under identical experimental conditions. The experimental study shows that the AC breakdown voltage of the HFO−N2 mixture under a slightly nonuniform electric field is close to that of the SF6−N2 mixture.[13]

Methods

Results

Conclusion