What is the displacement of a WYE-Delta or a Delta-WYE configuration?

In a WYE-Delta or Delta-WYE configuration, the phase displacement between the primary (typically the WYE) and secondary (typically the Delta) systems is crucial for understanding the phase relationships in three-phase power systems. The correct answer identifies the angle of 30° or 210° as the phase displacement.

This phase shift results from the transformation between WYE and Delta connections. In a WYE configuration, the phase voltages can be described as being at 0°, 120°, and 240° when referenced to a neutral point, while the Delta configuration results in line voltages that are directly related to phase voltages but shifted. Specifically, between a WYE and Delta configuration, the resulting displacement is 30°; hence, when viewing the angular relationships, one can interpret the result also at 210°, which is essentially the same angle as 30° but in the opposite rotation direction.

Knowledge of these displacements is essential for tasks such as load balancing and understanding fault conditions in electrical systems. The other angle choices (0°, 45°, 60°) do not accurately represent the unique phase relationships formed in these configurations, which is why they fall short in discussing the actual displacement encountered within WYE-Delta or