DYN11 and YNyN0 are both vector group notations used to represent the connections of three-phase transformers. The main difference between DYN11 and YNyN0 transformers is in the way the windings are connected and the phase shifts between the primary and secondary windings. Here are the main differences:

DYN11 transformer:

• In a DYN11 transformer, the primary winding is connected in a delta (Δ) configuration, the secondary winding is connected in a star (Y) configuration with the neutral grounded, and the tertiary winding (if any) is connected in a delta configuration.
• The phase shift between the primary and secondary windings is 30 degrees.
• The vector group notation for a DYN11 transformer is "Dyn11".

YNyN0 transformer:

• In a YNyN0 transformer, both the primary and secondary windings are connected in a star (Y) configuration with the neutral points extended but not connected.
• The phase shift between the primary and secondary windings is 0 degrees.
• The vector group notation for a YNyN0 transformer is "YnYn0".

In summary, the main differences are in the winding configurations and the phase shifts between the windings. DYN11 has a delta-connected primary and a star-connected secondary with a phase shift of 30 degrees, whereas YNyN0 has star-connected windings with neutral points brought out and no phase shift between primary and secondary.