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Mineral oil (MO) has been widely used in transformers because of its reasonable price and acceptable properties. Currently, alternative liquid insulations have been proposed with some excellent properties. Therefore, the mineral oil characteristics need to be enhanced for high performance to compete with such alternative liquid insulations. This paper aims to study the power frequency dielectric dissipation factor (tanδ) along with polarization and depolarization current (PDC) characteristics of the mineral oil-based nanofluid and natural ester (NE)-based nanofluid. Besides, Fourier-transform infrared spectroscopy (FT-IR) measurement of the test specimen was performed. Titanium dioxide (TiO2) and zinc oxide (ZnO) with 0.01% and also 0.03% volume concentration were used to mix with the unmodified liquid to create liquid insulation-based nanofluid. Then, unmodified mineral oil, unmodified natural ester, mineral oil-based nanofluid, and natural ester-based nanofluid were comparatively investigated. Tanδ at power frequency and the PDC characteristics of such liquids were examined. For PDC measurement, TiO2 clearly affected the polarization current and conduction loss factor, whereas ZnO evidently impacted the depolarization current and polarization loss factor. In the case of FT-IR test results, there was no significant change when the modified insulating liquid was compared with those of the unmodified insulating liquid. [ABSTRACT FROM AUTHOR]

The aim of this research is to improve the electrical properties of dielectric liquids. An examination of the dielectric properties of mineral oil‐based nanofluids was carried out, using three different nanoparticle types: titanium dioxide, zinc oxide, and barium titanate, each with a mean diameter not exceeding 100 nm. The test samples were divided into two groups, including mineral oil mixed with nanoparticles at a concentration of 0.01 and 0.03% volume fraction, respectively. Determination of the AC breakdown voltage of the unmodified mineral oil and the nanofluid samples was performed through testing at temperatures varying within the range of 35–90°C in accordance with the standards of IEC 60156. Furthermore, testing was also performed to determine the dielectric dissipation factor (tanδ) for each of the liquid samples according to IEC 60247. From the study, it was shown that the performance of nanofluid was significantly affected by increasing the temperature. It could be observed from the findings that the use of nanoparticles in creating mineral oil‐based nanofluids had potential to bring a number of advantages in terms of dielectric applications. [ABSTRACT FROM AUTHOR]

In this study, the AC breakdown (BD) voltages and partial discharge (PD) activities of mineral‐oil (MO)‐based nanofluids were investigated under controlled conditions. The aim of this research is to improve the dielectric properties of MO by amalgamation with various types of nanoparticles, i.e. semiconducting and dielectric nanoparticles. Two types of nanoparticles, i.e. titanium dioxide and barium titanate with mean diameters of <100 nm were used in the nanofluid samples prepared for the experiments. The AC BD voltages of the nanofluids were investigated according to IEC 60156. In addition, PD characteristics of the MO‐based nanofluids were examined including PD inception voltage (PDIV) characteristics and PD activity with a needle‐plane electrode configuration. The test circuit was set up in accordance with IEC 60270 and the experiment was performed in conformity with IEC 61294 at room temperature. The test results showed that the AC BD voltages of the modified liquids were clearly influenced by the type of nanoparticles added, with the AC BD voltages of the MO with nanoparticles being slightly higher than those of the unmodified MO used for comparison. Furthermore, the nanoparticles also demonstrated a propensity to increase the PDIV of the nanofluids compared with the PDIV of the MO. [ABSTRACT FROM AUTHOR]