DISPOSITIF DE SURVEILLANCE DE DEFAUT D'ALIMENTATION DE RELAIS DE PROTECTION NUMÉRIQUE

摘要

The present disclosure is to provide a power failure monitoring device of a digital protection relay capable of preventing a relay operation error and a data loss by determining a power failure when an electric power voltage being detected is dropped to be equal to or less than a prestored power failure reference voltage to enable a controller to perform a power failure preparation operation. The power failure monitoring device of the digital protection relay according to the present disclosure includes a voltage transforming unit (12) for dropping a voltage of an alternating current (AC) electric power to provide an electric power voltage signal representing an electric power voltage value, and a controller (15) for computing and storing a power failure reference voltage based on a preset rated electric power voltage and a power failure reference ratio with respect thereto, and for comparing the electric power voltage value, which is represented by the electric power voltage signal provided from the voltage transforming unit (12), with the stored power failure reference voltage to determine a power failure when the electric power voltage value is not greater than the stored power failure reference voltage.