What does the transformer vector group Dyn11 indicate about winding connections and phase displacement?

• A. Delta primary, Wye secondary with neutral grounded; LV phase is shifted by 30 degrees relative to HV (secondary lags by 30 degrees).
• B. Wye primary, Delta secondary with neutral grounded; LV phase is shifted by 0 degrees.
• C. Delta primary, Wye secondary with neutral grounded; LV phase leads HV by 60 degrees.
• D. Wye primary, Wye secondary with neutral grounded; no phase displacement.

Answer: (A)

Dyn11 encodes both winding connections and the angular relationship between HV and LV voltages. The first letter tells you the high-voltage winding is connected in Delta, while the second letter tells you the low-voltage winding is connected in Wye with its neutral grounded. The number 11 is the phase-displacement code: it corresponds to a 30-degree shift where the LV line voltage lags the HV line voltage by 30 degrees. In clock notation, 11 o’clock equals −30°, so the LV side is 30 degrees behind the HV side.

So, on a Dyn11 transformer, you have a Delta primary, a Wye secondary with a grounded neutral, and the LV phasor is displaced by 30 degrees behind the HV phasor. This differs from other vector groups that would pair different windings or produce zero or other phase shifts, such as a Wye–Wye with no displacement or a different 30/60-degree shift.