AC Dielectric Strength and Partial Discharge Activity in Naturel Ester and Naturel Ester-Based Fullerene Nanofluids

This paper aims to study the effect of fullerene (C60) nanoparticles (NPs) on AC breakdown voltage and partial discharge activity in natural ester (NE), namely FR3. The AC breakdown voltage (BDV) and partial discharge (PD) tests are performed according to IEC 60156 and IEC 60270 standards, respectively. The AC BDVs of natural ester (NE) are compared with those of nanofluids (NFs), considering five concentrations of fullerene NPs ranging from 0.1 to 0.5 g/L, while the partial discharge (PDs) activity was carried out only on two optimal concentrations giving the best improvements on the AC BDV (0.3 and 0.4 g/L). Furthermore, inception voltage (PDIV), average charge (Qavg), peak charge (Qpeak), as well as the number of PDs/s were compared. In addition, the phase-resolved PD pattern (PRPD) is also compared for the three liquids (i.e., NE and the two NFs). On the one hand, except for the 0.1 g/L NF, the investigated NFs show increased AC BDV, and the best improvement is about 13% compared to base liquid FR3. On the other hand, the addition of fullerene to FR3 natural ester decreases the PDIV and increases the number of PDs per second, while it decreases Qavg and Qpeak.