This guide concerns transformer connections in 3-phase distribution systems. Distribution systems are characterized by primary voltages up to and including 34.5 kV, usually have a preponderance of connected transformers with low-voltage windings below 1000 V and furnish electric service to consumers. The characteristics of the various transformer connections and possible operating problems under normal or abnormal conditions are treated. All combinations of Delta and Y, grounded and ungrounded, T connected, zigzag, and certain special connections are considered. Only two-winding transformers are included. |