Investigation of Persea Americana Oil as an Alternative Transformer Insulation Oil

Mineral insulating fluids have conventionally been used as insulating liquids in electrical equipment for over a century. These fluids serve as dielectrics and coolants. They are however known to be environmentally toxic and are highly flammable. Hence, they require costly fire protection schemes and deluge systems. Increasing awareness of environmental protection and fire safety is leading to accelerating trend of looking for plant based oil alternatives that are environmentally friendly. Increase in power rating of electrical equipment also calls for high temperature performance insulating oils. Plant based dielectric fluids have been found to defeat mineral oils in many of these aspects. They are nontoxic, possess better thermal properties and have excellent biodegradability. In order to reduce the adverse environmental impact and to improve the fire safety of transformers, there is an increasing demand for plant based insulating liquids as transformer insulating oils. This paper presents results of series of experiments that were performed to investigate the electrical, chemical, physical and thermal properties of food grade Persea americana ester (PAE) for possible use as insulation oil. For comparison, the corresponding properties of mineral insulation oil (MIO) in the same experimental conditions were also measured and compared with those of PAE. In this investigation, two different types of Persea americana oil samples consisting of extra virgin and refined PAE were tested. The obtained results show that the average electrical, chemical, physical and thermal properties of PAE meet the IEC and IEEE specifications for new natural liquid insulation oils. This may suggest that Persea americana oil can be tried as an alternative transformer liquid insulation.