Exploring the Decomposition Products of 1,3,3,3-Tetrafluoropropene and Perfluoro-(3-methylbutan-2-one) Gas Mixtures in Medium-Voltage Electrical Switchgear as Alternatives to SF6

María Luz Alonso; Rosa María Alonso; José Ignacio Lombraña; Jesús Izcara; Josu Izagirre

doi:10.1021/acsomega.1c02512

Exploring the Decomposition Products of 1,3,3,3-Tetrafluoropropene and Perfluoro-(3-methylbutan-2-one) Gas Mixtures in Medium-Voltage Electrical Switchgear as Alternatives to SF6

ACS Omega. 2021 Aug 12;6(33):21534-21542. doi: 10.1021/acsomega.1c02512. eCollection 2021 Aug 24.

Authors

María Luz Alonso¹, Rosa María Alonso¹, José Ignacio Lombraña², Jesús Izcara³, Josu Izagirre³

Affiliations

¹ Analytical Chemistry Department, Faculty of Science and Technology, University of the Basque Country (UPV/EHU), Barrio Sarriena s/n, 48940 Leioa, Bizkaia, Spain.
² Chemical Engineering Department, Faculty of Science and Technology, University of the Basque Country (UPV/EHU), Barrio Sarriena s/n, 48940 Leioa, Bizkaia,Spain.
³ Ormazabal Corporate Technology, Parque Empresarial Boroa, parcela 24, 48340 Amorebieta-Etxano, Bizkaia, Spain.

Abstract

In this work, binary and ternary gas mixtures of 1,3,3,3-tetrafluoropropene, HFO-1234ze(E), and perfluoro-(3-methylbutan-2-one), CF₃C(O)CF(CF₃)₂, with CO₂ and synthetic air, are presented as alternatives to SF6 in medium-voltage electrical equipment. They were used in four medium-voltage switchgear cubicles replacing SF6 gas, and after a period of time, under permanent 30 kV AC voltage, gas mixture samples were extracted and analyzed on the same day using a validated methodology based on gas chromatography (GC) coupled to mass spectrometry (MS) and thermal conductivity (TCD). CF₄ (tetrafluoromethane), C₂F₆ (hexafluoroethane), C₃F₆ (hexafluoropropylene), C₃HF7 (1,1,1,2,2,3,3-heptafluoropropane), CH₂F₂ (difluoromethane), and the cis and trans-C₃H₂F₄ (1,3,3,3-tetrafluoropropene) have been identified as decomposition products in these gas mixtures. In addition, a quantity of water has been observed, as well as CO in one of the cubicles. The most abundant decomposition products identified in gas mixture samples (C₃HF₇ and C₃F₆) together with water and CO content have been quantified using commercial gas mixture reference standards. The toxicity and global warming of the analyzed compounds are evaluated to determine the most adequate gas mixture among those studied as a candidate to substitute SF6.