ELECTRIC
POWER ASSOCIATIONS
OF
MISSISSIPPI
March 18-19, 2015 • Dixie EPA
CO U RS E DE S CRI P T I O N
The purpose of this course is to teach the common types of transformers and how
they are connected. Basic concepts of transformers and primary systems are
covered as well as single-phase connections. Single-phase distribution
transformers can be interconnected to provide three-phase power in a number of
different ways, providing a utility with the flexibility of meeting a variety of customer
needs. This program demonstrates and explains how three-phase delta
connections and three-phase wye connections are made. This program also
explains how to make delta-wye, wye-delta, and open bank connections.
COURSE GOALS
• Identify the characteristics that are common to most single-phase
overhead transformers.
• Explain the difference between delta and wye primary systems.
• Demonstrate how to make single-phase transformer connections.
• Demonstrate how three single-phase transformers can be connected
in a delta configuration on both the primary and secondary sides.
• Demonstrate how three single-phase transformers can be connected
in a wye configuration on both the primary and secondary sides.
• Illustrate a three-phase, three-wire, delta secondary connection.
• Illustrate a three-phase, four-wire, delta secondary connection.
• Illustrate a three-phase, four-wire, wye secondary connection.
• Troubleshoot all transformer banks
Demonstrate and explain how three-phase delta-wye and wye
delta connections producing 30 degrees of angular displacement
are made.
• Demonstrate and explain how open connections
are made.
• Recognize and use phasor diagrams for delta-wye,
wye-delta, and open connections.