This is the first Ester liquid filled power transformer designed and manufactured in Iran. Ester liquids are eco-friendly, biodegradable and non-toxic. Ester liquids can absorb large amount of moisture in transformer with no reduction of breakdown voltage. These properties of Ester liquid improve the condition of insulation materials in transformer and therefore extends the lifetime of transformer. Ester liquid’s flash point is higher than 250 °C. Smoke and ashes from burning of Ester are less toxic than mineral oil with much lower fire point around 140 °C.

Due to the installation site of this transformer which is 13 meters underground, plug-in bushings and ester liquid have been used for improving the safety of the transformer during faults.

Using plug-in bushings leads to more electrical safety and reduces dimensions of the transformer by removing air clearances which is needed in case of air bushings. This is an optimal solution for underground substations in terms of fire safety and space limitations.

The specifications of a typical Ester liquid filled power transformer manufactured successfully in Arya Transfo is showed in following table. 

                           Design Characteristic