This paper presents the potential of using treated used cooking oil as a potential dielectric liquid for high-voltage power transformers. The acidity of used cooking oil is higher than the prescribed limit of natural ester for power transformers. Hence, this paper proposes a combination of treatment methods to reduce the acidity of used cooking oil to less than 0.06 mg KOH/g. The treatment methods are: (1) alkaline refining, (2) bleaching and (3) synthetic silicate treatment. The physicochemical and electrical properties (acidity, color, density, flash point, viscosity, water content, breakdown voltage and dissipation factor) of the treated used cooking oil are measured according to standards. The results show that the acidity of the treated used cooking oil is 0.0182 mg KOH/g, which is 99.67% lower than the initial value of 5.4664 mg KOH/g. This acidity is achieved by implementing the following treatment methods: (1) alkaline refining using caustic soda (normality: 2.0N); (2) two cycles of bleaching with Fuller earth's adsorbent (concentration: 10 wt%) in each cycle; and (3) treatment with synthetic silicate absorbent (concentration: 15 wt%). In addition, combined treatment methods affect the color rating of the treated used cooking oil, where the color rating is L0.5. The breakdown voltage and dissipation factor at 90 °C of the treated used cooking oil are found to be 100 kV and 0.00688, respectively. The other physicochemical properties (density, viscosity and water content) of the treated used cooking oil fulfills the BS EN 62770 standard except for the flash point, with a value of 234 °C.

中文翻译：

---

废食用油作为油浸式电力变压器介电液的潜力


本文介绍了使用经过处理的废食用油作为高压电力变压器的潜在介电液体的潜力。使用过的食用油的酸度高于电力变压器天然酯的规定限值。因此，本文提出了综合处理方法，将废食用油的酸度降低至低于 0.06 mg KOH/g。处理方法为：(1)碱炼、(2)漂白、(3)合成硅酸盐处理。根据标准对处理后的废食用油的理化和电性能（酸度、颜色、密度、闪点、粘度、含水量、击穿电压和损耗因数）进行测量。结果表明，处理后废食用油的酸度为0.0182 mg KOH/g，比初始值5.4664 mg KOH/g降低了99.67%。该酸度是通过以下处理方法实现的：（1）用烧碱碱精炼（当量浓度：2.0N）； (2)每个周期用漂白土吸附剂(浓度：10wt%)漂白两个周期； (3)用合成硅酸盐吸收剂(浓度：15wt％)处理。此外，组合处理方法会影响处理后废食用油的色度等级，其中色度等级为L0.5。经处理的废食用油在 90 °C 时的击穿电压和损耗因数分别为 100 kV 和 0.00688。处理后的废食用油的其他理化特性（密度、粘度和含水量）除闪点值为 234 °C 外均符合 BS EN 62770 标准。