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

The displacement of a WYE-WYE or Delta-Delta bank is commonly understood as being either 0° or 180°. This is because these configurations are symmetrical in their phase relationships, and the voltages in a WYE configuration are referenced to a neutral point, leading to a phase displacement of either 0° (when in phase) or 180° (when they are opposing). In a Delta configuration, the phase relationships also yield similar results, leading to the conclusion that the displacement is fundamentally characterized by these two angles.

The other choices involve angles that are not relevant to the phase relationships inherent in WYE-WYE or Delta-Delta setups, as they suggest phase displacements that do not align correctly with the alternating current systems used in these configurations. Therefore, understanding the specific phase angles associated with these transformer banks is essential for effective management of electrical systems.