Enhancing the critical characteristics of natural esters with antioxidants for power transformer applications

Abstract

The energy demand of the whole world is dominated by petroleum products for centuries in the field of critical application like electricity. The application of mineral oil in power system equipment like transformer is potentially hazardous to environment. The exploitation of petroleum oil is running out of demand and in the near future, oil scarcity exists. This work focuses in identifying alternate dielectric for replacing traditional mineral oil. India is a tropical country, which produces vegetable oils like sunflower oil, palm oil, coconut oil, mustard oil, corn oil, soybean oil and rice bran oil profusely and it can be used as dielectric fluids in transformer. To be more proficient in the operation of transformer, these vegetable oils should be converted in to superior dielectric fluids. This work also embraces the individual and combinatorial effect of selected natural and synthetic antioxidants in natural ester. For investigation sunflower oil, rice bran oil, soybean oil and corn oil are chosen. The critical parameters like breakdown voltage, viscosity, flash point and fire point are calculated according to IEC and ASTM standards before and after addition of antioxidants with vegetable oils. Astoundingly it is found that the use of natural and synthetic antioxidants can enhance the critical parameters of natural ester for transformer application and the antioxidant activity in the natural ester is discussed. The interpolation functions are calculated based on the results obtained in minimum and maximum concentration of antioxidant added. These functions are used to predict the intermediate output variations caused for each antioxidant concentrations (in gram).