S11 series oil-immersed transformers Rated Power: 30~31500kVA Rated HV: 6,6. ... 3,10,11,15,20,35kV Rated LV: 220,380,400,415,433V Oil ... reduce temperature and improve transformer's overload capability.Oil-Immersed Transformer Insulation Structure: The transformer adopts class ... .60 31502800240000.50 S11 Series 30 to 31500kVA 3Phase Two Winding Oil mmersed Transformer