Optimization of transformer oil blended with natural ester oils using Taguchi-based grey relational analysis

Abstract The objective of the work is to improve the performance of mineral oil. To enhance the performance,mineral oil is blended with natural ester oils such as sunflower oil, palm oil,rapeseed oil and Olive oil. The key parameters of the blending mixtures are measured such as breakdown voltage, viscosity, flash point, fire point and acidity as per standards. In order to verify the repeatability and reproducibility of the above parameters, repeated measurements are taken. With the increase in mixing ratio, the performance of samples gets increased to some extent, after that, it started decreasing. The selection of optimal sample concentration based on the considered parameters is quite tricky. Therefore, it is vital to determine the optimal sample concentration based on the enhanced electrical, physical and thermal properties with respect to the mixture concentration. In this work, the selection of optimal mixed liquid insulation is performed by a grey relational analysis (GRA) method after carefully measuring the properties. It determines, Mineral oil and Sunflower oil mixing ratio 10:90 produces desirable performance compared to other samples. Validation has also been carried out on the optimized sample concentration. It is concluded that grey relational analysis is a possible method to determine the optimal sample concentration of mixed liquid insulation.