20 MVA transformer is a power transformer with a capacity of 20 megavolt-amperes (20,000 kVA). It is used to step up or step down voltage levels in electrical power systems. The specific voltage levels (primary and secondary) and other characteristics of the transformer, such as cooling type and connection type, will vary depending on the application. Here's a more detailed breakdown: MVA Rating: The "20 MVA" designation means the transformer can handle a maximum apparent power of 20 million volt-amperes. Voltage Levels: The primary and secondary voltage levels will be specified based on the application. For example, a 20 MVA transformer might step down voltage from 132 kV to 11 kV, or from 24.9 kV to 4.16 kV, among other possibilities. Step-Down Function: In many cases, 20 MVA transformers are used as step-down transformers, reducing high transmission voltages to lower distribution voltages that are suitable for industrial or commercial use. Cooling: 20 MVA transformers can be cooled by oil or air, with various cooling configurations available depending on the specific application and environmental conditions. Connections: Common connection types include Y-Δ (Wye-Delta), Y-Y (Wye-Wye), and Δ-Y (Delta-Wye). Impedance: A typical impedance value for a 20 MVA transformer is around 5-10%, which is important for voltage regulation and short-circuit protection. Efficiency: Most 20 MVA transformers are designed to be highly efficient, with typical efficiencies in the range of 98-99%.