Overview

This chapter covers the functions performed by high-voltage power transmission and distribution equipment in the electrical power industry. Basic transformer theory is discussed here to highlight the similarities in construction and operation of all transformers, whether they are low-power units or high-voltage transformers used in transmission and distribution. The transformer configurations used in single-phase and three-phase applications are discussed. In addition, the more specialized voltage and current transformers for high-voltage instruments as well as autotransformers are explained. The transformer section of this chapter includes a glossary of transformer terms for ready reference.

The circuit breakers discussed in this chapter are rated for more than 600 V. They operate on different principles than the more familiar low-voltage units and have different distinguishing features. (Residential low-voltage circuit breakers are discussed in Chap. 5.) The functions of high-voltage circuit switchers, reclosers, interrupter switches, and voltage regulators in power transmission and distribution systems are explained.

To make the most effective use of AC power, it is important that inductive reactances be minimized to bring the voltage and current waveforms into a closer phase relationship. The subjects of power factor and power factor correction are discussed, and the role of power capacitors in power factor correction is explained. The use of the kilovarmeter to monitor power factor and capacitive reactance during typical 24-hr periods is discussed.

The way in which rotary or static phase converters convert single-phase to three-phase power is explained. Power semiconductors are playing an increasingly important role in power rectification and...