Effects of Oxygen on the Insulation Characteristics of Eco‐Friendly Insulating Gas HFO‐1336mzz(E)/CO ₂

ABSTRACT HFO‐1336mzz(E)/CO 2 , an eco‐friendly insulating gas, garnered considerable interest recently as a potential substitute for SF 6 in gas‐insulated equipment. To reduce the precipitation of fluorocarbon gases and solids during the decomposition process of HFO‐1336mzz(E)/CO 2 gas mixture, O 2 is normally introduced as an additive. Herein, we investigated the influence of oxygen on the insulation performance of HFO‐1336mzz(E)/CO 2 under different electric field non‐uniformities by evaluating the breakdown voltage, PDIV, PDEV and decomposition characteristics. The findings indicate that in a quasi‐uniform electric field, the breakdown voltage of the gas mixture progressively increases with the oxygen volume fraction. Under the extremely non‐uniform electric field, both the breakdown voltage and PDIV initially rise and subsequently decline with the increase of oxygen volume fraction, reaching a peak at 6%. The PD decomposition analysis reveals that the addition of 4% oxygen can reduce the decomposition of HFO‐1336mzz(E), which is most beneficial to improve the comprehensive insulation performance of the gas mixture.