Power quality and the utility/customer interface

Power quality is a growing concern on electric power systems. Customers are requiring a higher quality of service as a result of more sensitive electronic and computer-controlled loads. Capacitor switching events and voltage sags associated with remote faults that never caused problems in the past now cause equipment tripping and even failures within customer facilities. Also, customer loads are generating increasing amounts of harmonic currents that can be magnified on the distribution system due to resonance conditions. This paper presents an overview of three important power quality concerns: harmonics; transients; and voltage sags.