Question

In per-unit equivalent circuits of practical three-phase transformers, under balanced three-phase operation, in which of the following connections would a phase-shifting transformer come up?

(a) Y-Y
(b) Y-Δ
(c) Δ-Δ

Answer 1

A phase-shifting transformer would come up in the Y-Δ connection in a practical three-phase transformer under balanced three-phase operation.

Step-by-step explanation:

A phase-shifting transformer would come up in the Y-Δ connection in a practical three-phase transformer under balanced three-phase operation in per-unit equivalent circuits. In the Y-Δ connection, the primary winding is connected in a Y formation, and the secondary winding is connected in a Δ formation. This configuration allows for phase shifting between the primary and secondary voltages.