Diffusional Behavior of New Insulating Gas Mixtures as Alternatives to the SF6-Use in Medium Voltage Switchgear

Abstract

Regarding the use of SF6 in medium voltage switchgear (MVS), a review of alternatives was encouraged by the European Parliament in Regulation No 517/2014. This is aimed at a new regulatory change, that is expected soon, which will include its prohibition, similar to what has happened with other fluorinated greenhouse gases in other fields, like refrigeration. Therefore, there is an urgent need to study the physical and chemical properties of alternative gas mixtures to determine if they are suitable to replace SF6. In this context, this work addresses the difusional analysis of new gases. Binary and ternary mixtures made of 1,3,3,3‑tetrafluoropropene (C3F4H2) and heptafluoroisopropyl trifluoromethyl ketone (C5F10O), using dry air as a carrier gas, were studied. The mixtures were analyzed using original equipment, composed of UV-Vis spectroscopy technology in a sealed gas chamber, which is similar to MVS. Consequently, an experimental equipment that monitors the concentration of a gas mixture online and a model that predicts the mixing process were designed and tested. The concentration profiles were obtained concerning both the time and position in the gas chamber, and the diffusional and convectional parameters were numerically calculated and optimized in an algorithm created in Scilab.

Stability Valorization of Hydrofluoroolefine HFO-1336mzzE and Its Mixtures under Arc Discharge Conditions

“…Therefore, the primary objective of this research is to investigate the stability of a HFO4E gas misture, when exposed to energy levels equivalent to 100 current setting maneuvers of 630 A and 24 kV. This study was conducted using a mixture of HFO4E gas and a vector gas (N 2 , CO 2 , or dry air) in an 80:20 (v/v) ratio, ,,, to ensure the required insulation performance, at various humidity and temperature conditions.…”

“…Furthermore, a previously validated method based on gas chromatography coupled to mass spectrometry (GC/MS-TCD) was used to identify and quantify the degradation products. , In addition, a near-infrared online analyzer (NIRQUEST) (900–1700 nm), which may potentially be implemented in industrial equipment, was used as a qualitative tool to determine the stability of HFO4E. Infrared analysis techniques have previously been used to study other SF 6 replacement gases. , Here, NIR is proposed to confirm that the amount of HFO4E remains constant, i.e., that there is no significant variation with respect to the total initial concentration value of HFO4E in the mixture.…”