Energy, and particularly electrical energy, is a commodity that mankind in general tends to take for granted. We switch on a light or our computer and expect an immediate power flow to energise it. Yet, the steady development and rapid progress that has been made in the transmission and distribution of electrical energy during the past 120 years or more may not have been possible but for the capability of linking generators, transmission lines, the secondary distribution systems operating at a variety of loads, with each at its optimum voltage. This linking of systems at different voltages has relied upon a simple, convenient and reliable device - the power transformer. The unique ability of the transformer to adapt the voltage to the individual requirements of the different parts of the system is derived from the simple fact that it is possible to couple primary and secondary windings of the transformer in such a way that their turns ratio will determine very closely their voltage ratio as well as the inverse of their current ratio, resulting in the output and input volt-amperes and the output and input energies being approximately equal. Coverage in this chapter includes a little of the theory of transformers, the major components involved in their manufacture, and the many different applications of the transformer technology in that are in everyday use.

Chapter Contents:

• 13.1 Introduction
• 13.2 Transformer action
• 13.3 The transformer as a circuit parameter
• 13.4 Core- and shell-form constructions and components
• 13.4.1 The core
• 13.4.2 The windings
• 13.4.3 Cooling
• 13.4.4 Insulation
• 13.4.5 Tank
• 13.4.6 Bushings
• 13.4.7 On-load tap-changer
• 13.5 Design features
• 13.5.1Dielectric design
• 13.5.2Electromagnetic design
• 13.5.3Short-circuit forces
• 13.5.4Winding thermal design
• 13.6 Transformer applications
• 13.6.1 Power station transformers
• 13.6.2 Transmission system transformers
• 13.6.3 HVDC convertor transformers
• 13.6.4 Phase-shifting transformers
• 13.6.5 Industrial transformers
• 13.6.6 Railway transformers
• 13.7 A few predictions of the future
• References

Inspec keywords: power transformers; potential transformers; transformer windings

Other keywords: voltage ratio; transformer windings; transformer technology; transmission lines; secondary distribution systems; current ratio; linking generators; electrical energy; power flow; optimum voltage; high-voltage power transformer design

Subjects: Transformers and reactors