This series of high-capacity oil-immersed power transformers covers rated capacities from 31,500 kVA to 420,000 kVA, with Class 1 (Type 22), Class 2 (Type 20), and Class 3 (Type 18) energy efficiency grades. Featuring a YNd11 connection group and 12–14% short-circuit impedance, they are designed for large-scale power transmission and distribution systems. Optimized for low losses and high reliability, they meet IEC and GB standards and are ideal for power plants, substations, and industrial facilities, supporting both step-up and step-down applications.