ABSTRACT
Phasors are essentially complex numbers with built-in sinusoidal time dependences. They are usually written as a complex number in polar form. This chapter discusses the phasors without explicitly including the time exponential. Voltages and currents are often written as phasors having their root mean square (rms) magnitude because these are usually the quantities of interest in a power system. Power systems are three-phase systems, in which the voltages and currents come in triples. There are two basic types of three-phase connections in common use, the wye (Y) and delta (Δ) connections. In the Y connection, all three phases are connected to a common point, which may or may not be grounded. In the Δ connection, the phases are connected end to end with each other. The advantage of using symmetrical components is that an unsymmetrical three-phase set of phasors can be analyzed in terms of three symmetrical systems of phasors.
