The Automatic Voltage Regulator is equipped with three (3) 16A outputs that will protect connected equipments from surges and other three (3) outputs will protect connected load "equipments" from any peaks, overloads and lightning. Its technology higher the voltage when its found too low or lower the voltage when too high. A phone line (Tel, fax, ADSL, etc.) can also be protected against lightning through its RJ11 connector.
The automatic voltage regulator is used to regulate the voltage. It takes the fluctuate voltage and changes them into a constant voltage. The fluctuation in the voltage mainly occurs due to the variation in load on the supply system. The variation in voltage damages the equipment of the power system. The variation in the voltage can be controlled by installing the voltage control equipment at several places likes near the transformers, generator, feeders, etc., The voltage regulator is provided in more than one point in the power system for controlling the voltage variations.
Working Principle of Voltage Regulator
It works on the principle of detection of errors. The output voltage of an AC generator obtained through a potential transformer and then it is rectified, filtered and compared with a reference. The difference between the actual voltage and the reference voltage is known as the error voltage. This error voltage is amplified by an amplifier and then supplied to the main exciter or pilot exciter.
Thus, the amplified error signals control the excitation of the main or pilot exciter through a buck or a boost action (i.e. controls the fluctuation of the voltage). Exciter output control leads to the controls of the main alternator terminal voltage.
Application of the Automatic Voltage Regulator
The main functions of an AVR are as follows:
It controls the voltage of the system and has the operation of the machine nearer to the steady state stability.
It divides the reactive load between the alternators operating in parallel.
The automatic voltage regulators reduce the overvoltages which occur because of the sudden loss of load on the system.
It increases the excitation of the system under fault conditions so that the maximum synchronising power exists at the time of clearance of the fault.