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Electrical characteristics of natural ester based nanofluid

In this paper, the dielectric properties of natural ester based nanofluids were investigated. This research represents the improvement of the electrical properties, AC breakdown and negative lightning impulse breakdown strength, of the natural ester (FR3) by amalgamation with nanoparticles. Two types of nanoparticles i.e., Titanium dioxide (TiO2) and Zinc Oxide (ZnO), with a mean diameter of less than 100 nm were used in this experiment. The nanofluid samples, a natural ester merged with nanoparticles, were prepared in three steps. First, the natural ester was divided into four groups. The first group was merged with 0.01% concentration of TiO2 and the second group was merged with 0.03% concentration of TiO2. The third group was merged with 0.01% concentration of ZnO and the fourth group was merged with 0.03% concentration of ZnO. Second, the nanofluid samples were dispersed using a magnetic stirrer. Finally, the ultrasonic dispersant technique was applied to the prepared nanofluids to be homogeneity. To measure AC breakdown voltage of the natural ester based nanofluids, the oil breakdown tester was employed and the testing experiment was performed according to IEC 60156. In addition, the negative lightning impulse breakdown characteristic of the natural ester based nanofluid was investigated with the needle-sphere electrodes in accordance with IEC 60897. A tungsten needle with tip radius of 40 μm was utilized as the high voltage electrode and the 13 mm diameter brass sphere was used as the grounded electrode. The gap distance was fixed as 15 mm. The test results showed that the AC breakdown property of the modified liquids was clearly influenced by the type of nanoparticles added. The AC breakdown voltage of the natural ester with nanopaticles was slightly higher than that of the unmodified natural ester. Additionally, both TiO2 and ZnO nanoparticles demonstrated their ability to increase negative impulse breakdown voltage of the nanofluids. These tests indicated that such nanoparticles have good potential to be used with natural ester to improve the dielectric properties.