How can calculate Dy1 Dy11 vector group of transformer?

To calculate the Dy1 and Dy11 vector groups of a transformer, first determine the primary and secondary winding configurations. The "D" indicates a delta connection for the primary winding, while "y" indicates a wye connection for the secondary. The numeral indicates the phase shift in hours, with Dy1 representing a 30-degree phase shift (1 hour) and Dy11 representing a 330-degree phase shift (11 hours). The phase shift can be calculated by measuring the angle between the primary and secondary line voltages using vector diagrams or phasor analysis.