How many possible phase displacements can all three-phase conventional transformer banks have?

The correct answer is two because a three-phase conventional transformer bank can typically be connected in either a delta-delta (Δ-Δ) or a wye-wye (Y-Y) configuration, resulting in two main phase displacement options.

In a delta connection, the phase windings are connected in a triangular configuration, while in a wye connection, they meet at a common neutral point. This results in a 30-degree phase shift between the primary and secondary sides for a delta-wye connection, or no phase shift for a wye-wye connection.

Thus, the two standard phase displacements reflect the types of transformers commonly used in the industry and the configurations they can adopt. Understanding this helps lineman apprentices comprehend how different transformer arrangements impact power distribution and system performance.