ABSTRACT
The chapter presents the fundamentals of balanced three-phase systems, starting with the two basic connections of these systems, namely, Y and Δ, and their characteristic features. This is followed by explaining the basic approach in analyzing balanced three-phase systems by transforming the Δ connection to Y and deriving an equivalent single-phase system. Because three-phase systems are primarily power systems, power relations in these systems are then discussed, including instantaneous and complex power, power measurement, and power factor correction. Three-phase systems are almost universally used for the generation, transmission, and distribution of electrical energy because of the many advantages they offer compared to single-phase systems. Practical three-phase systems are nominally balanced under normal operating conditions, that is, their voltages and currents possess a certain symmetry. The chapter highlights the advantages of three-phase systems and considers the overall structure of power systems.
