Digital Automatic Voltage Regulator(D-AVR) TOSATEX3000
Functions

Standard functions
D-AVR system provides the following standard functions that are essential for generator control.

• Sequential Control
  Starting and normal stop of Excitation System
• Automatic Voltage Regulator(AVR)
  To adjust the generator terminal voltage constant so that it agrees with the reference (90R).
  
• Under Excitation Limiter(UEL)
  To prevent the AVR from reducing generator excitation to such a low value that the generator would fall out of synchronism
  
• Over Excitation Limiter(OEL)
  To prevent the AVR increasing generator excitation to a value so high and a time so long that the generator rotor thermal capability would be exceeded.

• V/F Limiter ( VPFL)
  To prevent the generator from the over-flux condition by monitoring the ratio voltage / frequency.
  
• Power System Stabilizer ( PSS)
  To improve the damping of electric-mechanical
  resonance mode between the generator and the tie-line. It provides supplemental control signal to AVR by detecting instantaneous deviation of the generator output power (Delta P) or frequency (Delta f).
  
• Automatic Follow-up of 90R(AFU)
  To make 90R of the standby channel following that of the working channel.
  
• Manual Excitation Controller(MEC)
  To maintain the field current constant so that it agrees with 70R. It is standard that the MEC is exclusively used for commissioning test.
• Reactive Current Compensator(RCC)
  To reduce the reactive current among generators paralleled on the same bus by supplying compensation signal corresponding to the reactive current of each generator to the reference (90R).
• Over Excitation Protector(OEP)
  To protect the generator from field over current beyond OEL limit ting.
• 84V
  The generator voltage detecting functions for voltage build-up sequence.
• 60AVR
  The voltage difference detecting function between 2 VTs for sensing the VT circuit failure.
• Transient Response Recording
  To record the transient response signals for tests or the just before and after data at an accident.
  
• Generator auxiliary control (option)
• Synchronize control (option)