RAGPK gives an alarm for generator underexcitation conditions and provides tripping for loss-of-excitation. A relay operating condition is detected when the generator consumes reactive power from the system in order to maintain the active power output as received from the prime mover.
The RAGPK protection is suitable for all types of synchronous machines having a linear operating characteristic that is easily coordinated with the thermal capability curve of the machine. The relay has an overcurrent supervision function and a two stage voltage supervision element that may be used separately for alarm or tripping.
