ABSTRACT
This chapter provides an introduction to the more common power quality terms. It explains how power quality factors interact in an electrical system. The difficulty in quantifying power quality concerns is explained by the nature of the interaction between power quality and susceptible equipment. Power frequency disturbances are low-frequency phenomena that result in voltage sags or swells. These may be source or load generated due to faults or switching operations in a power system. Power system transients are fast, short-duration events that produce distortions such as notching, ringing, and impulse. Electromagnetic interference (EMI) refers to the interaction between electric and magnetic fields and sensitive electronic circuits and devices. The mechanism of coupling EMI to sensitive devices is different from that for power frequency disturbances and electrical transients. Power quality interdependence means that two or more machines that could operate satisfactorily by them do not function properly when operating together in a power system.
