Electric Power Quality

This chapter discusses electric power quality, which generally applies to the goodness of the electric power supply, its voltage regulation, its frequency, voltage wave shape, current wave shape, level of impulses and noise, and the absence of momentary outages. Electric power quality studies generally span the entire electrical system, but the main points of emphasis are in the primary and secondary distribution systems. There are two main classes of electric power quality disturbances: the steady-state disturbance that lasts for a long period of time (and is often periodic) and the transient. Because power quality is often stated in terms of voltages and currents, the main instrumentation needed to assess power quality relates to bus voltages and line and load currents. In terms of voltages, usually bus voltages are measured using potential transformers because isolation from the power circuit is desirable and because power system voltages are usually too high to measure directly. Furthermore, the analysis techniques for power quality studies are explained in the chapter. © 2005