manpreet Best Answer 3 years ago

What is Automatic Voltage regulator  (AVR)?

manpreet 3 years ago

Hii... Rahul
An automatic voltage regulator is a thyristor type voltage controller which will maintain the output voltage of the alternator whenever voltage fluctuations occur due to varying loads. AVR achieved this by controlling the excitation of the alternator. Whenever a voltage dip occurs then it will increase the excitation and vice versa.

There are following main functions of an AVR

1. controls the voltage of the system and operation of the machine nearer to the steady state stability.
2. It divides the reactive load between the alternators operating in parallel.
3. The automatic voltage regulators reduce the overvoltages which occur because of the sudden loss of load on the system.
4. It increases the excitation of the system under fault conditions so that the maximum synchronizing power exists at the time of clearance of the fault

manpreet 3 years ago

In the context of power system, suppose you are generating electricity  at V volts. It is highly essential that the voltage always  remain at V volts no matter what happens. In order to achieve it we use AVR.

AVR senses the o/p voltage and transmits it to a comparator which compares V with the present output. The error if present is amplified and fed to the field generator which adjusts its o/p current which in turn adjusts the main field of the generator and maintains the voltage at V volts all the time. 

manpreet 3 years ago

 It protects your sensitive electronic equipment from brownouts and over-voltages. Uncorrected voltage fluctuations gradually degrade the life of electronic components, potentially causing premature failure. An AVR not only adjusts voltages to safe levels, but also provides surge protection against electrical surges and spikes and lightning