Experimental Study of Nanoparticles' Impact on AC Breakdown Voltage of Aged Vegetable Oil

This study investigates the AC breakdown characteristics of aged nanofilled vegetable oil (VO) with CuO and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{SiO}_{2}$</tex> nanoparticles, aiming to assess their impact on insulation properties under ageing conditions. AC breakdown voltage measurements were conducted using ASTM D1816 and IEC 60156 standards, employing different electrode gap distances (1 mm and 2.50 mm, respectively). <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{SiO}_{2}$</tex> and CuO nanoparticles were used at concentrations of 0.035 % and 0.05 %. The VO samples were aged for <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$0,7,14$</tex>, and 28 days at 110° C under open conditions. Statistical analysis using normal and Weibull distribution were as performed on the experimental results. The introduction of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{SiO}_{2}$</tex> nanoparticles in the VO significantly increased the AC breakdown voltage, particularly at a concentration of 0.05 %, resulting in a 62.30 % increase. Similarly, a 54.15 % increase was observed with a <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$0.05 \% \ \text{SiO}_{2}$</tex> concentration in MO. Additionally, all samples exhibited a decrease in AC breakdown voltage at the end of the ageing period. Overall, it contributes to the understanding of VO as an alternative insulating oil and highlights the potential of nanoparticles in enhancing transformer insulation systems under realistic ageing conditions.