Improved Estimation of Uniform AC Electric Breakdown Field Strength of HFO1234ze(E)

Abstract

The gas number-density reduced AC electric breakdown field strength (E/N) bd in pure HFO1234ze(E) is investigated from 0.45 bar to 4 bar with a variable electrode gap distance of 4.88, 10.00 and 13.32 mm. The aim of the present contribution is to clarify two aspects that are contradictorily reported in literature. Firstly, the pressure dependence of (E/N) bd and secondly the fact that the first breakdown value in HFO1234ze(E) can be significantly different from subsequent breakdowns in the same arrangement. To clarify these two aspects, particular attention is paid to improving the experimental procedure and to consider the role of electrode surface roughness and solid dissociation products caused by the breakdowns. The methodology of experimentation has been improved, compared to standard breakdown experiments: a freshly polished set of electrodes is used for every breakdown measurement and the electrode surface is preconditioned with low-energy breakdowns in CO 2 to reduce the possibility of micro-protrusions. A quantitative analysis confirms the improved and reproducible surface characteristics due to the preconditioning. The (E/N) bd values measured this way, show an increase with pressure up to 3 bar in 4.88 mm gap distance. In addition, it is confirmed that HFO1234ze(E) is a non-self-restoring gas. Subsequent breakdowns can be significantly lower than the first one across the measured pressure range and this decrease in breakdown strength increases, as energy input to the breakdown becomes higher.

Robust approximation rules for critical electric field of dielectric gas mixtures

“…In the search for alternatives to sulphur hexafluoride, SF 6 , industry and scientific communities are considering a wide range of options. One such option that has been heavily studied [5,11,29,30] is (1E)-1,3,3,3-Tetrafluoroprop-1-ene (C 3 H 2 F 4 ), often abbreviated to HFO-1234ze(E). This gas is one of an emerging generation of hydrofluoroolefins (HFOs) originally targeted for use as refrigerants in place of traditional hydrofluorocarbons.…”

“…Driving the effort towards replacing SF 6 is considerable investment in academic and commercial research performing dielectric breakdown experiments [5,6] or swarm experiments [7,8] to characterise insulating gases. There are many complexities and challenges in adequately performing and interpreting measurements of such experiments in their varying geometries (e.g.…”

Partial discharge induced decomposition and by-products generation properties of HFO-1234ze(E)/CO2: a new eco-friendly gas insulating medium

“…The 90% HFO-1234ze(E)/10% SF 6 has a critical electric field of 360 Td, similar to pure SF 6 [9,15]. Basu et al investigated the as numberdensity reduced AC electric breakdown field strength of HFO-1234ze(E) [16]. Chachereau and Franck explored the effective ionization coefficients of HFO-1234ze(E)/N 2 and HFO-1234ze(E)/CO 2 gas mixture using a Townsend pulse experiment and pointed out that HFO-1234ze(E) has an electric strength comparable to that of SF 6 at 130 KPa [17].…”