ABSTRACT
Transformers are important components of electrical power systems, allowing to step up voltage for transmission and step it down for distribution. We start this chapter by studying magnetic circuits in order to gain a better understanding of transformers. After reviewing these devices, we continue our study of AC systems by looking into three-phase systems, that is, three AC voltages and currents at the same frequency but with different phase angles. Most electrical power systems are based on three-phase circuits. Among the major reasons for their use in power systems is that they provide constant total power. The chapter ends with a study of harmonics, or multiple values of the fundamental frequency, which can create load unbalance and detrimental current in the neutral. Harmonics can be created by a variety of reasons, including nonlinear electronic circuits to convert DC to AC, and vice versa such as rectifiers and inverters.
