AC Breakdown Voltage and Partial Discharge Activity in Synthetic Ester and Synthetic Ester-Based Zirconia Nanofluid

Abstract

This paper aims to study the AC breakdown voltage (AC BDV) and partial discharges (PDs) activity in pure synthetic ester (SE), namely Midel 7131, and synthetic ester-based zirconia (ZrO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> ) nanofluids (NFs). The AC BDV of pure SE is compared with NFs for five concentrations ranging from 0.1 g/L to 0.5 g/L of ZrO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> (20 – 30 nm) NPs, while the partial discharge (PD) inception voltage and number of PDs/s were compared with the NF at 0.4 g/L ZrO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> ; this concentration gives the optimal improvement on AC BDV. The AC BDV is conducted on sphere-sphere electrode configurations and the PDs test on needle-plan electrodes. The phase-resolved PD pattern is also compared for the two liquids. Under AC 50 Hz stress, the investigated NFs show increased AC BDV, increased PDIV, and a reduction of the number of PD than pure SE. Conformity tests conducted on the AC BDV and PDIV experimental results show that except for AC BDV data of 0.1 g/L ZrO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> Nf with normal distribution, AC BDV, and PDIV data obey both normal and Weibull distributions.