Electrical Engineering ⇒ Topic : Three-phase Transformer Connections

Three-phase Transformer Connections

Virtually all power distribution is by poly-phase system of voltages. Three-phase transformations may be made with the use of properly connected single-phase transformers. These connections are in extensive commercial use. The most frequently used connections are the following :

• Primary Y secondary Y.
• Primary Δ secondary Δ.
• Primary Δ secondary Y, or vice-versa.
• Primary and secondary open Δ.
•  Primary T secondary T (Scott connection)

Thus the most common connections are Y-Y, Δ-Δ, Y-Δ, Δ-Y, open delta or V-V and Scott connection or T-T connection