Voltage regulation
degree to which a device's output voltage remains nominal
In electrical engineering, voltage regulation is a measure of the difference in voltage between the sending and receiving ends of a transmission system or distribution system. On one end of these systems is the source, where the power is received, and on the other end is the load, where the power is sent to. Voltage regulation involves measuring the difference in the voltage at each end.
Electric utility companies use some electrical equipment to maintain the voltage constant magnitude value transmitted or distributed along the power line, such as tap changer, voltage regulator, capacitor etc.