Requirements for electrical power become more challenging every day in terms of both quality and
quantity. ‘‘Quality’’ means that consumers need stable voltage without distortions and interruptions.
‘‘Quantity’’ means that the user can draw as much load as needed without reducing the quality of the
supply. These requirements come from industry as well as from domestic consumers, and each
requirement influences the other. Maintaining voltage magnitude within a specified range is an import-
ant component of power quality. Power transformers and feeders impose their own impedance, and the
amount of voltage drop depends on the loads and, consequently, the currents that flow through them.
Voltage magnitudes decrease along the feeder, which means that consumers at the end of the feeder will
have the lowest voltage.