S11(13,14)-M oil-immersed distribution transformer is a kind of fully sealed transformer, with a core made of high-quality high-permeability cold-rolled oriented silicon steel sheet with full-diagonal joints and holeless binding, and oil tank designed and manufactured with fully closed corrugated structure, and beautiful appearance and small footprint. It adopts vacuum filling process to completely remove the air bubbles in the coil and the moisture in the oil tank to improve the stability of insulation. The transformer oil is isolated from the atmosphere, effectively preventing and slowing down the deterioration of oil quality and insulated moisture, enhancing the reliability of product operation. Its normal operation is maintenance-free, which improves social benefits, making the product widely used in agricultural networks.