This series of three-winding oil-immersed power transformers covers rated capacities from 31,500 kVA to 240,000 kVA, with Class 1 (Type 22), Class 2 (Type 20), and Class 3 (Type 18) energy efficiency grades. Featuring a YNa0d11 connection group and a 100/100/50% winding capacity distribution for step-down applications, they support customizable short-circuit impedance combinations (HV-MV 8–11%, HV-LV 28–34%, MV-LV 18–24%). Optimized for low losses and high reliability, they meet IEC and GB standards and are ideal for large-scale power plants, high-voltage substations, and industrial power distribution systems.