What is the process for hermetically sealed transformer oil filling?

The process for hermetically sealed transformer oil filling involves several key steps. First, the transformer is evacuated to remove moisture and air, ensuring a vacuum environment. Next, transformer oil is heated to reduce viscosity, facilitating easier filling. The oil is then pumped into the transformer through a filtration system to eliminate impurities. Finally, the filling is completed under controlled conditions to maintain the hermetic seal, preventing contamination and ensuring optimal performance.