A hermetic transformer is an electrical device that converts one form of electrical energy into another form. The term “hermetic” means that the oil inside the transformer is hermetically sealed. This type of transformer is generally used in high voltage and high current systems. Hermetic type transformer consists of primary and secondary windings, similar to classical transformer structures. High voltage electrical energy coming to the primary winding is transferred to the secondary winding via magnetic induction and low voltage energy output is obtained from this winding. The oil inside the transformer is used for both cooling and insulation purposes. Sealing the oil prevents external factors from damaging the transformer and ensures the protection of the parts inside. Hermetic type transformers are generally used in industrial facilities, energy distribution systems and large-scale infrastructure projects. Their reliability and durability allow them to find a wide range of applications.