Which of the following configurations causes circulating currents due to opposite phase?

The configuration that causes circulating currents due to opposite phase is Delta-wye. This is because the Delta-wye transformation involves changing the connection from a delta configuration, where the phases are connected in a triangle, to a wye configuration, where they are connected in a star shape.

In this transformation, the phase shift causes the voltages and currents to be misaligned, leading to circulating currents within the system. These circulating currents occur due to the different voltage levels at the phase connections, resulting from the phase relationships. The Delta configuration allows for higher phase currents that do not equate equally with the lower currents in the Wye configuration, creating a scenario where currents circulate.

In contrast, the other configurations, such as Delta-delta or Wye-wye, maintain phase relationships that do not lead to the same situation with opposite phases, ultimately minimizing or eliminating circulating currents. Therefore, Delta-wye is specifically recognized for these characteristics related to opposite phases resulting in circulating currents.