Enhancement of Breakdown Strength and Stability of Transformer Oil by Flaxseed, Blackseed, and Castor Oils Blending Based Novel Nanofluid via Green Synthesis Revolution

Abstract

The development of a reliable, environmentally safe, and economic insulating oil for the transformer is an endless effort of the electrical industry. Mineral oil (MO), traditionally used, presents challenges including high cost, environmental impact, and limited availability. Consequently, research has shifted towards alternative solutions, aligning with green energy and environmental conservation goals. Natural ester oil has gained keen attention due to its complete biodegradability and widespread availability. This study explores alternative options, including a blend of vegetable oils (Blackseed, Castor, Flaxseed, and Mustard), aiming to enhance transformer insulation and cooling efficiency through this novel nanofluid. A novel nanofluid was synthesised using different ratios of proposed oils to produce a 300 mL sample blend of vegetable oil containing 0.03 g (0.0001 wt%) of green-synthesised SiO2 nanoparticles (average size ∼20–30 nm). These nanoparticles were fabricated using an eco-friendly method based on Moringa leaf extract, aligning with Sustainable Development Goals (SDGs). This sample was prepared for testing and validation at the advanced High Voltage Laboratory in accordance with the IEC-60156 standard to evaluate dielectric properties. Furthermore, thermal stress was applied to the proposed samples to replicate real-time conditions. Moreover, conducted comparative analyses between a newly proposed vegetable oil-based nanofluid and conventional MO, emphasising dielectric properties, including AC and DC breakdown voltage (BDV) and stability. Results demonstrate that the eco-friendly vegetable oil-based nanofluid surpasses traditional MO by a significant 19% margin in breakdown strength. Stability assessments reveal only a 0.32% reduction in BDV for the proposed nanofluid after 6 years of simulated equivalent ageing, contrasting with a 19% reduction observed in MO. This contemporary research highlights the potential of the proposed nanofluid as a promising alternative to conventional MO, as evidenced by comprehensive testing and analysis.