Dielectric liquids are used for insulation and cooling purpose in all electrical equipment. Transformer is the essential equipment in power generation system. From earlier days, the mineral oil is used for dielectric liquids. But mineral oil has poor biodegradability. It produces hazards to environment. It is not environment friendly. Due to this drawback of mineral oil, environment friendly vegetable oils are used for an alternate dielectric liquid. For this work, palm oil has chosen for the experiments. Investigations of various parameters like Breakdown Viscosity (BDV), Viscosity, Flash and fire point are done according to their standards. From the experimental analysis, the properties of palm oil are compared with standards. The average breakdown strength of palm oil is higher than mineral oil. Comparing the experimental result, cost and availability, the palm oil has selected for blend with mineral oil. The values of breakdown voltage, viscosity and fire point are presented. The transformer efficiency is better by using palm oil. The results showed that the combination of mineral oil and palm oil enhanced the breakdown voltage. The Antioxidants are used to improve the properties of palm oil mixture. Interpolation functions are calculated with different concentration of antioxidants.